VLBI Software Documentation
Field System
SNAP Commands
W. E. Himwich and N. R. Vandenberg
NVI, Inc./GSFC
Operations Manual
NASA/Goddard Space Flight Center Version 9.3
Space Geodesy Program September 1, 1997
This manual contains detailed descriptions of the SNAP commands available in the Field
System. Each command is described on a separate page. Commands are ordered alphabetically.
Please refer to the SNAP Language manual for the specifications of the language itself,
including a description of control commands and general syntax.
The subsections of this first section contain reference information that applies to many
commands.
1.1 Command Descriptions
In this manual, each command is described on a separate page. For each command, the
information is provided:
command - function (equipment)
The command name and a few words that describe its function are given at the top of each page.
If the command is restricted to certain types of equipment, that information is given in
parentheses. For example, the rec command is applicable only to VLBA drives, and the title
will include the words (VLBA drive). Most commands have no restrictions, although they may
behave slightly differently for different equipment. Mark III commands are applicable to Mark IV
unless there is a separate Mark IV command description.
Syntax: command=list of parameters
The command syntax is shown first. The command name and the list of parameters are shown.
The various forms of the command are described in the Comments section. Any combination of
upper case and lower case letters may be used in typing a command. All commands are converted
to lower case before they are processed.
Response: command/list of response parameters
The response (if any) to the command is given with the list of parameters appearing in the
response. Normally the response to a command has an identical list of parameters to the
command itself, followed by any monitor parameters. All responses to commands are displayed
in lower case letters only.
Settable parameters:
This part of the page describes each parameter in the "Syntax" line that can be specified by the
operator. The allowable range of values for each parameter is given. The default value, if any, is
given. A default value is obtained by entering a null for a particular parameter. The parameter
value specified in the previous issuing of this command may be obtained by entering * instead of
a value. Entering ? as the first parameter results in a response containing the parameters specified
in the most recent issuance of this command. If any parameter value is found to be invalid,
command interpretation stops at that point and an error message is generated.
Monitor-only parameters:
Each parameter in the "Response" that does not appear in the "Syntax" is described in this
section. These are parameters that cannot be specified by the operator, but are monitored or
calculated by the Field System.
Comments:
The final section of the page provides further descriptions of the way in which the command
works. These comments often describe the algorithm that was used in implementing the
command, and outline specific conditions under which the command should be used.
The phrase "MAT module functions available" in the comments section means that the following
additional types of parameters may be used. This is available for those Mark III modules that
have MAT communications.
module=test/reset Issues an MAT reset to this module only.
module=alarm Resets the alarm on this module.
The following syntax is valid for those commands which state that "MCB module functions are
available" in the Comments section of the command description.
module=addr Sends the module its base address and length. This sets the module's MCB
address space.
module=test Checks the module's address. An error message in response to this command
indicates that the module needs to be sent its address space.
1.4 Module and Detector Mnemonics
The Field System makes use of mnemonics for Mark III, Mark IV, S2, and VLBA equipment in
SNAP commands. Displays of mnemonics are always two characters, but many forms of module
names are allowed when entering commands. This is a convenience for the operator who does
not have to remember the exact two-character mnemonic.
The SNAP commands that pertain to total power radiometry allow the operator to specify
different detectors in the equipment. Detectors are specified by using a mnemonic. When the
Field System displays mnemonics they are always two characters, but different forms of the
detector names are allowed when entering commands. This is a convenience for the operator who
does not have to remember the exact two-character mnemonic.
Valid mnemonics for modules and detectors are listed in the tables on the following pages.
| Field System Module Mnemonics | ||
| Module | Standard mnemonic | Other allowed mnemonics |
| Mark III modules | ||
| video converters | vn, n=1-f | vcn, n=1-15, 1-f |
| IF distributor | if | ifd |
| formatter | fm | form |
| tape transport | rc | rec, tp, tape |
| high density heads | hd | |
| S/X receiver | rx | |
| IF3 distributor | i3 | if3,ifd3 |
| S2 modules | ||
| tape recorder | rc | rec, tp, tape |
| VLBA modules | ||
| baseband converters | bn, n=1-f | bcn, bbcn, n=1-15, 1-f |
| IF distributor 1, channels A&B | ia | ifa, ifb, ib, ifab |
| IF distributor 2, channels C&D | ic | ifc, ifd, ic, ifcd |
| formatter | fm | form |
| tape recorder | rc | rec, tp, tape |
| Groups of modules | ||
| all modules which have been set up | all | |
| odd video or baseband converters | odd | |
| even video or baseband converters | even | |
| Field System Detector Mnemonics | ||
| Detector | Standard mnemonic | Other allowed mnemonics |
| Mark III detectors | ||
| video converters | vn, n=1-f | vcn, n=1-15,1-f |
| IF distributor channel 1 | i1 | if1 |
| IF distributor channel 2 | i2 | if2 |
| IF3 distributor | i3 | if3 |
| S2 detectors | ||
| none | ||
| VLBA detectors | ||
| baseband converters, USB | nu, n=1-f | bnu, bcnu, bbcnu,
n=1-15,1-f |
| baseband converters, LSB | nl, n=1-f | bnl, bcnl, bbcnl,
n=1-15,1-f |
| IF distributor 1, channel A | ia | ifa |
| IF distributor 1, channel B | ib | ifb |
| IF distributor 2, channel C | ic | ifc |
| IF distributor 2, channel D | id | ifd |
| Groups of detectors | ||
| all odd video converters | odd | |
| all even video converters | even | |
| all odd baseband converters USB | oddu | |
| all odd baseband converters LSB | oddl | |
| all even baseband converters USB | evenu | |
| all even baseband converters LSB | evenl | |
2.0 On-Line Help
The entire documentation for each command is available as on-line help in the Field System. The
help command will display the information for a specified command on the screen during Field
System operations. The information that is listed is identical to that found on the pages of this
manual.
Refer to the page with the help command description.
3.0 SNAP Command Descriptions
Syntax: antenna=message,message, ...
Response: antenna/response,response, ...
Settable parameters:
message message to be sent to the antenna in the exact form required by the pointing software.
Each message between commas will be sent separately.
Monitor-only parameters:
response response of the antenna to the message. This response is either ack or an error
message sent by the antenna.
Syntax: azeloff=az,el
Response: azeloff/az,el
Settable parameters:
az Offset in azimuth, in numeric angle/degrees format. Response is in decimal degrees.
el Offset in elevation, in numeric angle/degrees format. Response is in decimal degrees.
Monitor-only parameters: none
Comments:
The antenna will move to the offset position when this command is issued. To return to the
on-source position, issue this command with zero offsets.
Syntax: bbcnn=freq,ifsource,bwu,bwl,avper,gainmode,gainu,gainl
Response: bbcnn/freq,ifsource,bwu,bwl,avper,gainmode,gainu,gainl,
lock,USBpwr,LSBpwr,serno,err
nn is the BBC index number corresponding to its position in the rack, 01 to 14. Not all racks
have all BBCs.
Settable Parameters:
freq L.O. frequency in MHz, between 450.00 and 1050.00, inclusive. No default. This frequency range is greater than the normal range over which the BBC is specified to lock (500 to 1000 MHz) to allow for testing.
ifsource I.F. input source, one of A, B, C, D. No default.
bwu Bandwidth for USB in MHz. One of 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16. Default 2.
bwl Bandwidth for LSB in MHz. One of 0.0625, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16. Default bwu.
avper Averaging period in seconds for TPI. May be 0, 1, 2, 4, 10, 20, 40, or 60 seconds. A value of 0 results in 1/80 sec averaging time. Default 1. The averaging period is common to both upper and lower sideband. The averaging period is synchronous with the 1 pps.
gainmode Gain control mode, either agc or man. Use agc (default) for automatic gain control, man to set a gain value. The gain mode is common to both sidebands.
gainu Gain value for USB. This is a valid parameter only if gainmode is man. May be any value between -99.0 dB and 12.0 dB. Step size is linear in voltage. The actual gain setting is reported as a monitor value. Default is the current USB gain level. This parameter is not implemented.
gainl Gain value for LSB. This is a valid parameter only if gainmode is man. May be any
value between -99.9 dB and 12.0 dB. Step size is linear in voltage. The actual gain setting is
reported as a monitor value. Default is the current LSB gain level. This parameter is not
implemented.
Monitor-only Parameters:
lock L.O. lock status, lock or unlock.
USBpwr Power in upper sideband in counts. Range 0 to 65535, nominal operating level is 16000.
LSBpwr Power in lower sideband in counts. Range 0 to 65535, nominal operating level is 16000.
serno Module serial number, decimal.
err Module timing error indication, 1pps or no 1pps.
Comments:
This command sets up the baseband converters in the VLBA rack. This command is analagous to
the Mark III vcnn commands.
Unlike the output of most other commands which have no embedded blanks, the output for this
command is columized for easy reading of gains and power levels.
MCB module functions are available. See section 1.0 of this manual.
The power-up setting for the gain control is manual control with a value of +6 dB. If the IF level
is nominal coming in to the BBC then the operating level for the AGC is +6 dB. Normal setting
during an experiment is agc.
To hold the gain at a given value, switch to man gain control. The gain value will stay at the
value it had when the AGC was changed to man. Then use agc to return to AGC control. This
method is used for radiometry by onoff and fivpt.
On terminals wired like the geodetic racks, the following table shows which BBCs have which IF
inputs available.
| BBC-to-IF input availability | |
| BBC numbers | IF input channels |
| 1, 2 | A, B, C, D |
| 3, 4, 5, 6, 7, 8 | A, C |
| 9, 10, 11, 12, 13, 14 | B, D |
CAUTION: This command does not check whether you have specified a valid IF source for the
BBC.
Syntax: beam1=angle
beam2=angle
beam3=angle
beama=angle
beamb=angle
beamc=angle
beamd=angle
Response: beam1/angle
beam2/angle
beam3/angle
beama/angle
beamb/angle
beamc/angle
beamd/angle
Settable parameters:
angle full-width half maximum beam size, displayed in decimal degrees of arc.
Monitor-only parameters: none
Comments:
The beam1/2/3 and beama/b/c/d commands are applicable for Mark III and VLBA systems,
respectively. The command pairs beam1/a, beam2/b, and beam3/c are synonomous.
The beam size for the sky frequency for each IF channel may be specified with these commands.
The commands flux1/2/3 and fluxa/b/c/d use the sizes specified as beam1/2/3 and
beama/b/c/d, respectively, to calculate the apparent flux.
There is no default for the beam size unless the appropriate IF distributor command (ifd or if3
for Mark III systems, ifab or ifcd for VLBA systems) and the lo and upconv commands
have been issued. If these commands have been issued, then the beam size will default to the
beam size calculated from the appropriate LO and upconverter frequencies and the antenna
diameter found in the antenna.ctl control file. The formula is:
beam size (radians) = 1.05*c/(freq*diaman)
Issuing a beamx=... command will change the calculated values of the fluxx command to
invalid quantities. Reissue a corrrect fluxx=... command to recalculate fluxes.
Syntax: bit density=bpi
Response: bit density/bpi
Settable parameters:
bpi Bit density in bits per inch.
Monitor-only parameters: none
Comments:
This command specifies the total bit density including all header and parity bits. The specified bit
density and the formatter set-up determine the default speed for the st command.
The bit density can be set to any positive value less than 232. Useful values are 33333 for
Mark III data-replacement format and 34020 for the VLBA non-data-replacement format.
Useful values are 56250 for Mark III data-replacement format and 56700 for the VLBA non-data-replacement format at high density (thin tape).
When calculating speeds from bit densities it is useful to remember that for a nominal per track
bit rate of 4 MBit/sec, the Mark III data-replacement format actually generates 4.5 MBit/sec and
the VLBA non-data-replacement format generates 4.536 MBit/sec.
Syntax: break
Response: none
Comments: The currently-executing procedure is stopped after the current command is finished.
The procedure stack is popped to the next higher level. This is an immediate execution
command.
NOTE: This command is not implemented.
Syntax: cable=message
Response: cable/value
Settable parameters:
message ASCII character to be sent to counter.
Monitor-only parameters:
value cable cal reading
Comments:
When issued with no parameters this command sends a request for a reading to the HPIB counter
which is connected to the phase cal cable measurement system.
The ibad.ctl control file must contain an entry with mnemonic CA and the device name.
If your counter returns a non-standard response, you can control the parsing of the response, by
placing the uncommented line below in your stcmd.ctl file:
*command seg sbpa bo eq
cable qkr 13xx 01 FF
Where the value xx is the character position to started decoding the response at. The normal
cable command uses xx=04. If xx=00, the cable command will try to find the right place to
begin decoding the response at on its own, looking for the first character that might be part of a
number. You can examine the response from the counter to determine where to begin the
decoding by reading it back with an hpib=ca command.
Syntax: cal=on/off
Response: none
Settable parameters:
on/off on to turn cal on, off to turn off. No default.
Monitor-only parameters: none
Comments: This command sets a VHF switch on the HPIB. The ASCII message is A1 to turn cal
on, A2 to turn cal off. The ibad.ctl control file must contain an entry with the mnemonic CL
and the device name.
Syntax: caltemp1=temp
caltemp2=temp
caltemp3=temp
caltempa=temp
caltempb=temp
caltempc=temp
caltempd=temp
Response: caltemp1/temp
caltemp2/temp
caltemp3/temp
caltempa/temp
caltempb/temp
caltempc/temp
caltempd/temp
Settable parameters:
temp temperature of cal signal, in degrees K.
Monitor-only parameters: none
Comments:
Calibration temperatures, for either Mark III or VLBA systems, may be specified with the
caltemp1/2/3 and caltempa/b/c/d commands, respectively. The commands tsys1/2/3
and tsysa/b/c/d use the temperatures specified as caltemp1/2/3 and caltempa/b/c/d
respectively. The command pairs caltemp1/a, caltemp2/b, and caltemp3/c are
synonomous.
Syntax: check=list
Response: check/list
Settable parameters:
list The list of mnemonics for modules to be checked. Only mnemonics for the equipment
identified in the equip.ctl control file are valid in this command. Standard module
mnemonics are allowed. If the list of modules to be checked is empty, then chekr will not
check any modules.
Monitor-only parameters: none
Comments:
As modules are set up by SNAP commands, they are automatically added to the list of modules
being checked by chekr. This command can be used to remove and reinstate modules on the
list.
The entire list of modules to be checked may always be specified by listing the appropriate
modules. However, the list of modules already being checked may also be modified by entering
* as the first parameter, followed by the list of modules to be added or deleted from the existing
list. Deletion is indicated by a leading minus sign. For example,
check=*,ifd,-rc
will cause the IF distributor to be added to the list of modules being checked and the tape
transport to be removed from the list, while the check status of all other modules remain
unchanged.
If no modules are currently being checked then the word disabled is displayed.
The displayed list of modules always consists of the standard 2-character mnemonic, i.e. the ones
listed on the reference page at the front of this manual. Station-specific mnemonics may be used
for station-specific modules.
Note: In the current Field System version, for VLBA systems, the head position is checked but
only some of the DAR module and REC functions are checked.
Syntax: cont
Response: none
Parameters: none
Comments:
This command must be issued after a halt to get the schedule going again. It has no effect if no
halt was actually issued. This is an immediate execution operator command.
Syntax: data valid=record,playback
Response: data valid/record,playback
Settable parameters:
record Flag is on (default) or off.
playback Playback enable is use (default) or ignore.
Monitor-only parameters: None.
Comments:
This command can be used to set and monitor the value of the data valid and playback enable
flags written to the tape.
Syntax: date
Response: date/year,day
Settable parameters: None.
Monitor-only parameters:
year Current year.
day Current day of year.
Comments:
This command is included to allow display of the year and day of year in the log display window,
which normally only shows the hour, minutes, ands seconds of the log entry time tags. The year
and day of year are guaranteed to be consistent with the displayed hour, minutes, and seconds of
the log entry time-tag for the response.
Syntax: decode=channel,mode,counter
Response: decode/channel,mode,data
Settable parameters:
channel Channel a (default) or b to be decoded.
mode Type of data to be read. Choices are auxilliary data, synch, crc word, time, data bits, or error counts (default).
counter Error counter control: byte (default), frame, reset.
Monitor-only parameters:
data Data returned according to mode specified in control command.
err sspppppp (s=synch errors, p=parity errors) Note that monitored error values are error counts, not rates.
syn 8 - character synch word
time two words: ydddhhmm and sssssccc, where ccc = checksum
data three sets of 32 data bits
aux two sets of 8 characters of auxiliary data
crc pass/fail for CRC check
Comments:
MAT module functions available. CRC check is reliable only in bypass reproduce mode.
Most Mark III drives cannot decode in double speed, so this command will probably fail in this
mode. Old VLBA drives that use the Mark III bit synchronizer may have this problem also.
Syntax: dqa=duration
Response: dqa/duration,Asampler,Atrack,Aparity,Aresync,Anosync,Acalamp,
Acalphs,Bsampler,Btrack,Bparity,Bresync,Bnosync,Bcalamp,Bcalphs
Settable Parameters:
duration The duration of the analysis in seconds. Default 1 sec, max 5 seconds. Set up the
command with dqa=duration. Subsequent commands dqa will make a measurement. For each
measurement, the DQA module is started, allowed to run for duration and then stopped. The
accumulated counters are then read out.
Monitor-only Parameters:
Asampler Sampler for the A channel signal, 0 if unknown or in the form nnsd, nn=baseband converter number, s=sideband u or l, d=data sample bit m or s.
Atrack Track with the A channel signal on it, as set up in the repro command.
Aparity Measured parity error rate for A channel, per Mbyte.
Aresync Measured resync rate for A channel, per Mbyte.
Anosync Measured nosync rate for A channel, per Mbyte.
Acalamp Measured phase calibrator amplitude for A channel, in units of voltage percentage.
Acalphs Measured phase calibrator phase for A channel, degrees.
Bsampler Sampler of the B channel signal, 0 if unknown or in the form nnsd, nn=baseband converter number, s=sideband u or l, d=data sample bit m or s.
Btrack Track with the B channel signal on it, as set up in the repro command.
Bparity Measured parity error rate for B channel, per Mbyte.
Bresync Measured resync rate for B channel, per Mbyte.
Bnosync Measured nosync rate for B channel, per Mbyte.
Bcalamp Measured phase calibrator amplitude for B channel, in units of voltage percentage.
Bcalphs Measured phase calibrator phase for B channel, degrees.
Comments:
The data quality analyzer (DQA) is a formatter sub-module. It extracts phase cal and measures
parity errors and re-synch rates. The dqa command is comparable to the Mark III decode
command plus the capabilities of program pcalr. Normally you would use the check2c1/2
procedures during Field System operations.
Channels A and B are the recorded tracks as specified in the repro command. To measure
parity errors, the tape should be moving (use the st command) with record disabled. The phase
cal can be measured in bypass or reproduce mode. For bypass measurements, the group enables
must be turned on with the enable command, and the general record enable must be turned on
with the st command.
The sampler reported for a track is determined from the set-up of the cross-point switch by the
form command. If barrel-rolling and/or fan-in or -out are enabled, the displayed source will be
the nominal source for that track, but may not actually correspond to the data analyzed. If fan-out
is being used in a system with an analog cross-point switch, the reported source will be zero for
tracks beyond the first in a fan-out group.
Phase-cal results will be meaningless for the following cases: fan-out, fan-in, barrel-rolling
enabled, VLBA format, tracks that contain magnitude bits.
The output from this command is columized for easy reading when there are no errors, i.e., in
bypass mode.
Syntax: echo=set
Response: none
Settable parameters:
set on to turn echo on, off to turn off (default). Any external communications are echoed in
the log display window.
Monitor-only parameters: none
Comments:
Immediate execution operator command for MAT and/or MCB and/or RCL communications
and, at some stations, antenna communications also.
For MCB communications, each byte is displayed as
bytes sent to the MCB [nxx]
bytes received from the MCB <nxx>
where n is normally a blank. n is + for the first byte of the address when data is being written to
the module. The address or data is xx, represented as two hex characters. MCB control bytes are
displayed with special 3-letter mnemonics:
[SYN] hex 16 synchronization byte
<ACK> hex 06 acknowledge
<NAK> hex 15 not acknowledge
<DC1> hex 11 data control 1
<DC2> hex 12 data control 2
For MAT communications, most of the data bytes are printable ASCII characters which are
displayed simply as the character. The unprintable ASCII characters are displayed as [xxx],
where xxx is shown in the table below. The "del" character (127) is displayed as [del].
0 1 2 3 4 5 6 7 8 9
nul soh stx etx eot enq ack bel bs ht
1 lf vt ff cr so si dle dc1 dc2 dc3
2 dc4 nak syn etb can em sub esc fs gs
3 rs us
For RCL communications, each piece of information is displayed as
information sent to the RCL [xxx]
information received from the RCL <xxx>
where xxx is a representation of the data in an appropriate format. Information going to the RCL
is always displayed in order of: the name of the command being sent followed by the parameters
for that command. Information returned by the RCL is always displayed in the order of: the error
response code, and if there is no error, the parameter values returned in the response. The names
of the commands, and the order of the parameters sent and received is the same as that in ISTS's
S2-RT User's Manual, Appendix A. In addition whenever possible menomonics are
substituted for numeric parameters. Error and parameter menonics correspond closely to those in
the appendix of ISTS's manual. Remote errors are displayed as numeric values until a successful
ERROR DECODE command has been completed for that error code. Effectively this means that
the mnemomic is not used in the display of remote errors until the second time the error is
encountered after the most recent Field System start. If the value of a parameter that is normally
displayed as menomic doesn't correspond to the value of a known mnemonic for that parameter,
the hex value will be displayed.
For the TIME READ command the Field System's raw times immediately before and after the
call to rcl time read are displayed in curly braces {} immediately after the returned data.
The Field System's raw time is the number of centiseconds since the last boot.
Syntax: enable=track1,track2, ... trackn
Response: enable/track1,track2, ... trackn
Settable parameters:
track1, ... n List of tracks to be enabled/disabled. Mark III track numbers between 1 and 28, and by group. Groups specified by gn, n=1 to 4:
g1 includes tracks 1,3,5,7,11,13.
g2 includes tracks 2,4,6,8,10,12,14.
g3 includes tracks 15,17,19,21,23,25,27.
g4 includes tracks 16,18,20,22,24,26,28.
A null list (i.e. enable=) disables all tracks.
Monitor-only parameters: none
Comments:
MAT module functions available. The use of * as a parameter is not supported by this command.
Note that a VLBA or Mark IV track number equals the Mark III track number plus three.
Consequently, odd Mark III tracks are even VLBA or Mark IV track numbers and vice-versa. See
the Track Assignment Tables in the System Set-up Manual. Also VLBA group numbers equal
Mark III group numbers minus one, but the VLBA groups include additional tracks. Note that
this command uses Mark III track and group numbers.
Syntax: enable=list-of-groups
Response: enable/list-of-groups
Settable parameters:
list-of-groups List of track groups to be enabled/disabled. Groups are specified by gn, n=0 to 3.
A null list (i.e. enable=) disables all tracks. For mode D, a single track to be recorded may be
indicated by setting list-of-groups to dn, n = 1 to 28. The group within which Mark III track n
occurs will be enabled.
Monitor-only parameters: none
Comments:
The use of * as a parameter is not supported by this command.
This command enables groups of tracks in the VLBA recorder. Tracks may not be individually
enabled. The form command sets up the track assignments with the cross-point switch. In mode
D, an entire group of tracks is enabled. The VLBA form command must be used to specify
which track so that only that track has data going to it. It is not possible to record in mode D for a
Mark III rack/VLBA drive combination.
g0 includes Mark III tracks 1,3,5,7,11,13.
g1 includes Mark III tracks 2,4,6,8,10,12,14.
g2 includes Mark III tracks 15,17,19,21,23,25,27.
g3 includes Mark III tracks 16,18,20,22,24,26,28.
Note that a VLBA or Mark IV track number equals the Mark III track number plus three.
Consequently, odd Mark III tracks are even VLBA or Mark IV track numbers and vice-versa. See
the Track Assignment Tables in the System Set-up Manual. Also VLBA group numbers equal
Mark III group numbers minus one, but the VLBA groups include additional tracks. Note that
this command uses VLBA group numbers.
Syntax: enable=stack1,stack2
Response: enable/stack1,stack2
Settable parameters:
stack1,stack2 Stack to be enabled. May be s1 (stack1), s2 (stack2), or null.
Monitor-only parameters: none
Comments:
MAT module functions available. The use of * as a parameter is not supported by this command.
Syntax: et
Response: et/acknowledgement
Parameters: none
Comments:
Tape motion is stopped when this command is issued. For Mark III, the record bit is disabled. For
Mark IV, the enabled heads are not changed. For VLBA, no change is made in the track group
enables. Reproduce mode is not changed; the low tape sensor is not changed.
For Mark IV, see the st command for how to set up bypass mode.
For S2, the selected transports are stopped.
Examples:
For Mark III, when et is issued the following MAT commands are sent.
#94=%0xxxxxxx$ turn general enable bit off, same enabled tracks
#94=)07200000$ send stop command, with standard rate generator
For Mark IV, when et is issued the following MAT commands are sent.
#94=%0xxxxxxx$ turn general enable bit off, same enabled tracks
#94=)08530000$ send stop command, with standard rate generator
Syntax: ff
Response: ff/acknowledgement
Parameters: none
Comments:
The tape is moved forward at high speed. For Mark III, the record bit is disabled and the low tape
sensor is turned on. For VLBA, all track groups are disabled and the low tape sensor is turned on.
For S2 drives, the selected transports are moved forward at the transport's fast forward speed.
For drives other that the S2, the tape is moved at the "schedule" speed value as specified in the
equip.ctl control file. This is the speed assumed in the SNAP schedule file for positioning
the tape with the fastf procedure.
Use the sff command and sfastf procedure for possibly faster tape motion.
Syntax: fivept=axis,rep,pts,stp,intp,dev
Response: fivept/axis,rep,pts,stp,intp,dev,cal,beam,flux
Settable parameters:
axis Axis system for scan.
hadc = Hour Angle/Declination (default)
azel = Azimuth/Elevation
xyns = X/Y, +X East
xyew = X/Y, +X South (unimplemented)
rep Number of repetitions: -10 to -1 and 1 to 10 allowed. Default is -2. Negative repetition counts are described in the fivpt manual.
pts Number of points on each axis, if even, it is increased by 1. pts must be between 3 and 31. Default is 7.
stp Step size for distance between points, in multiples of a beamwidth. Default is 0.5.
intp Integration period, 1 to 10 seconds.
dev Mnemonic for the device to be used as the detector. Standard devices are allowed. Note
that for Mark III equipment, the video converter USB or LSB was set up with the vc command.
The module which has the specified detector must have been set up. The IF distributor must be
set up and, for Mark III, must be in remote. Default detector is i1 for Mark III, ia for VLBA.
Display-only parameters:
cal Calibration noise source temperature in degrees K. This is determined from the last caltempx commands in conjunction with the patch (Mark III) or bbc (VLBA) command for the specified device.
beam The full width half maximum beam size degrees. This is determined from the last beamx commands in conjunction with the patch (Mark III) or bbc (VLBA) command.
flux The apparent flux of the source. This is determined from the last fluxx commands in
conjunction with the patch (Mark III) or bbc (VLBA) command.
Comments:
The parameters should be setup with a fivept=... command. A scan is started by issuing a
simple fivept command (i.e. with no parameters), this will determine the current values of the
display only parameters and then schedule an external program, fivpt, which then uses the
Field System to perform the necessary measurements. fivpt must be included in the
fspgm.ctl control file so that it will automatically be initialized when the Field System is
started. See the fivept manual in Volume 2.
The scan is performed about the current commanded position. Any offsets that are in use are
included. If the scan is successful the total offsets for the selected axis type are updated.
It is recommended that nothing else be done, e.g. running a schedule, while this command is
executing. Since this command may run for an extended period of time, a mechanism has been
supplied for aborting: enter sy=brk fivpt. The program will then return the antenna to the
last good offset for each axis. If there was no good offset measurement on an axis, then the
original offset is used.
In order for this command to work, the following conditions must be met: (1) the detector device
have been setup by the Field System, (2) the lo and upconv commands have been issued, (3)
the IF distributor or IF3 module has been setup by the Field System and is in remote (Mark III
only), (4) the appropriate beamx=... and caltempx=.... must have been issued. If a Mark
III video converter is used as the detector then the patch command must have been issued as
well. If estimates of performance based on the source flux are desired, then the appropriate
fluxx=... command must have been issued as well.
Two procedures must be available: calonfp and calofffp, which are used by fivpt to turn
the noise diode on and off respectively. The recommended form for these procedures is:
calonfp: calon
!+1s
sy=go fivpt &
calofffp: caloff
!+1s
sy=go fivpt &
calon and caloff are local procedures that do whatever is necessary to turn the noise source
on and off.
Syntax: flush
Response: none
Parameters: none
Comments:
This command re-initializes the operator procedure stack, unblocks the operator command
stream, and terminates execution of the current procedure in the operator stream. There is no
effect on the schedule command stream. This is an immediate execution operator command.
Syntax: flux1=model,flux1,angle1,angle2,flux2,angle3,angle4
flux2=model,flux1,angle1,angle2,flux2,angle3,angle4
flux3=model,flux1,angle1,angle2,flux2,angle3,angle4
fluxa=model,flux1,angle1,angle2,flux2,angle3,angle4
fluxb=model,flux1,angle1,angle2,flux2,angle3,angle4
fluxc=model,flux1,angle1,angle2,flux2,angle3,angle4
fluxd=model,flux1,angle1,angle2,flux2,angle3,angle4
Response: flux1/model,flux1,angle1,angle2,flux2,angle3,angle4,
corr,aflux
flux2/model,flux1,angle1,angle2,flux2,angle3,angle4,
corr,aflux
flux3/model,flux1,angle1,angle2,flux2,angle3,angle4,
corr,aflux
fluxa/model,flux1,angle1,angle2,flux2,angle3,angle4,
corr,aflux
fluxb/model,flux1,angle1,angle2,flux2,angle3,angle4,
corr,aflux
fluxc/model,flux1,angle1,angle2,flux2,angle3,angle4,
corr,aflux
fluxd/model,flux1,angle1,angle2,flux2,angle3,angle4,
corr,aflux
Settable parameters:
model source model, one of gaussian, disk, twopoints
flux1 flux density of the first source component, Janskys
angle1 first angular dimension of the first component
angel2 second angular dimension of the first component
flux2 flux density of the second source component, Janskys
angle3 first angular dimension of the second component
angle4 second angular dimension of the second component
Monitor-only parameters:
corr correction divisor
aflux apparent flux density
Comments:
Source models, for either Mark III or VLBA systems, may be specified with the flux1/2/3 and
fluxa/b/c/d commands, respectively. The pairs of commands flux1/a, flux2/b, and
flux3/c are synonymous.
The commands fluxx use the source model and the beam size specified by the corresponding
beamx to calculate the apparent flux density. The parameter model determines which model is
used and which parameters have meaning. Parameters which have no meaning for a given model
will not be displayed before the corr parameter.
If model is gaussian, then the source is assumed to consist of up to two, possibly elliptical,
Gaussian brightness distributions. flux1 gives the flux density value for the first component.
angle1 and angle2 specify the diameters along the two principal axes. angle2 defaults to
angel1. flux2 gives the flux density value for a second concentric optional Gaussian distribution,
default value 0. angle3 and angle4 give the principal axes of the second component. angle4
defaults to angle3.
If model is twopoints, then the source is assumed to consist of two equally bright points.
flux1 is the total flux density of the two points. angel1 is their angular separation.
If model is disk, then the source is assumed to consist of a uniform circular disk brightness
distribution. flux1 is the total flux density. angel1 is the diameter of the disk.
Once the model is specified, the fluxx command will use the appropriate beam size to calculate
the apparent flux density of the source when the beam is centered on the brightness distribution.
The approximations given in Dave Shaffer's antenna check-out memo (see the Antenna
Performance manual) are used to compensate for the finite size of the sources relative to the
beam. Note that these are only approximations and become very poor as the correction divisor
approaches a value of two. Further note that very few sources are correctly represented by one of
these three models. This command gives a crude approximation to the true apparent flux density.
Issuing a source=... or a beamx=... command will automatically change the value of the
aflux parameters to be a negative, invalid, number until a correct fluxx=... command is
issued again. It is recommended that procedures that include the source=... command and
the appropriate fluxx=... commands be used to command sources when doing flux density
measurements.
See the description of the fivept and onoff commands for more details on the use of the
apparent flux density values.
Syntax: form=mode,rate,input,synch,aux
Response: form/mode,rate,input,synch,test,sign,run/set,rem/lcl,
pwr,daytime
Settable parameters:
mode Matrix output mode to tape. Choices are a, b, c, d. Default b.
rate Sample rate in Mbits/sec. Choices are 0.125, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0. Default 4.0.
input Source of data. Choices are nor (default), ext, crc.
aux Auxiliary data, up to 12 hex characters. Default is no change. If more than 12 characters are given, only the first 12 are used. If aux has been specified either now or implicitly by a pass, lvdt, or stack command, then the parity command will check its validity.
synch Synch test on (default) or off.
Monitor-only parameters:
test synch test fail or ok
sign synch voltage + or -
run/set switch setting run or set
rem/lcl switch setting, rem or lcl
pwr power interrupt detected, ok or pwr
daytime clock reading in format: ydddhhmmss.ss
Comments:
MAT module functions available.
It may take the formatter up to 4 seconds to re-synch itself if a change is made to a low sample
rate. During this time the read-back may not be accurate. This module must be reset manually
using the front panel pushbutton in order to clear error conditions; then turn off alarm remotely.
The eight LEDS on the rear panel of the formatter give some error conditions which are not
available remotely.
The auxiliary data field for the formatter is automatically filled with the tape head offset by the
pass, lvdt, and stack commands.
Syntax: form=mode,rate,fan,barrel
Response: form/mode,rate,fan,barrel,rev,rack,error
Settable Parameters:
mode The recording mode,choices for the mode are m, a, b1, b2, c1, c2, e1, e2, e3, e4, and dn, where n=1 to 28. No default. Modes a, b, b1, b2, c1, c2, e1, e2, e3, e4 and dn correspond to the traditional Mark III modes. For the bx and cx modes, x corresponds to the sub-pass recorded (odd Mark III tracks for b1 and c1, even Mark III passes for b2 and c2). For the dn modes, n corresponds to the Mark III track number recorded. For the ex modes, x corresponds to the Mark III group number recorded. Mode m uses the sampler track assignments and formatter track enables specified by the trackform and tracks commands.
rate Sample rate in Mbits/sec. Choices are 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, and 32. Default 4. For Nyquist sampling this selection must be twice the bandwidth set-up used in the bbc commands
fan The fan-in or fan-out ratio. Currently, the only choices are 1:4, 1:2, and 1:1, where on a per channel or track basis, the number before the colon is the number of sampled channels and the number after is the number of tracks. Default 1:1.
barrel Barrel-roll mode. Currently the only choice is off, which is the default.
Monitor-only Parameters:
rev Formatter firmware revision number as an integer.
rack Rack ID, reported as a hex value.
error Error status, okay or the hex value.
Comments:
The Mark IV formatter clock is set with the fmset program. After setting or resetting the formatter time, issue a
sy=run setcl offset & command to reset the Field System time.
Since the Mark IV recorder does not include group enables, some of the traditional Mark III
mode names used in mode have numbers appended to them to distinguish which sub-pass,
group, or track is being recorded.
Some combinations of rate and fan cannot be accommodated by the formatter. No output that
would require more than 16 MHz nominal data rate per track is supported. Specifically a rate of
32 and a fan of 1:1 is impossible. Some combinations of fan and rate cannot be
accommodated by the recorder. Any combination of rate and fan that would imply a nominal
data rate per track of 0.125 MHz or less for high density recording (thin tape) is not supported.
Any combination of rate and fan that would imply a nominal date rate per track of less than
0.125 MHz for low density recording (thick tape) is not supported.
For the time-being, in order to help facilitate debugging of the formatter in the field, the status of
the setable parameters is logged when the formatter set-up is changed. This information is logged
in the form of the output of the low-level MAT commands that return this information.
Additionally, whenever the formatter times out or reports an unknown command error (error
"7"), the command that resulted in the time-out or the unknown command error response is
logged. These debugging features will be removed in a subsequent version.
chekr does not currently support checking of the formatter. However, the set-up of the
formatter can be monitored by entering a form command. If any of the displayed values do not
agree with the last value commanded, then the formatter is not in the last commanded state.
Syntax: form=mode,rate,fan,barrel
Response: form/mode,rate,fan,barrel,rev,genstat,mcbstat,hdwstat,sfwstat,intstat
Settable Parameters:
mode The recording mode, reboot (see below) to reboot the CPU, or configure to cause the formatter to perform a hardware configuration. Choices for the mode are prn, v, m, a, b, b1, b2, c, c1, c2, and dn, where n=1 to 28. Default b. Modes prn, m, a, b, b1, b2, c, c1, c2, and dn imply Mark III data replacement format. prn selects pseudo random noise to be sent to all tracks including system tracks. Modes a, b, and c correspond to the traditional Mark III modes. Mode dn is the same as Mark III mode D, where n corresponds to the Mark III track on which the data are written. Mode v implies VLBA non-data replacement format. Modes b1 and c1 are the same as the even VLBA recorder tracks of modes b and c respectively; b2 and c2 are for odd VLBA recorder tracks. Modes m and v use the sampler track assignments and formatter track enables specified by the trackform and tracks commands. The system tracks are disabled except in prn mode.
rate Sample rate in Mbits/sec. Choices are 0.25, 0.5, 1, 2, 4, 8, 16, and 32. Default 4. For Nyquist sampling this selection must be twice the bandwidth set-up used in the bbc commands
fan The fan-in or fan-out ratio. Choices are 1:4, 1:2, 2:1, and 4:1, where on a per channel or track basis, the number before the colon is the number of sampled channels and the number after is the number of tracks. Default 1:1.
barrel Barrel-roll mode. Choices are: off, 8:1, and 16:1, where the number before the colon
is the number of tracks to roll-over. Default off.
Monitor-only Parameters:
rev Formatter firmware revision number, displayed as x.xx.
genstat General status, ok or the hex value of hex address 20.
mcbstat Communications status, ok or the hex value of hex address 21.
hdwstat Hardware status, ok or the hex value of hex address 22.
sfwstat Software status, ok or the hex value of hex address 23.
intstat Internal status, ok or the hex value of hex address 24.
Comments:
rate and fan combinations that imply more than 8 Mbits/sec of data per tape track or less than
0.25 Mbits/second of data per tape track are not permitted. The tape clock rate is set to be 9/8 of
the implied data bit rate per track for Mark III modes, and 9.072/8 of the impled bit-rate per track
in VLBA mode.
This command syntax applies to VLBA formatters only. The many possible error conditions for
the formatter are monitored and reported by chekv (not yet implemented).
MCB functions are available. The formatter CPU can be reset manually. After manual reset you
must issue the command form=addr to re-initialize the module.
CAUTION: Issuing this command with an equals, =, causes a formatter reconfiguration which
will put the formatter into a busy state for up to 8 seconds.
The VLBA formatter clock is set with the fmset program. After setting or resetting the
formatter time, issue a sy=run setcl offset command to reset the Field System time.
In VLBA mode the serial status register is loaded with the hardware ID (from equip.ctl) in
the most significant byte and the micron position of the head is stored in BCD in the two least
significant bytes; negative values are indicated by the highest order bit of these two bytes being
turned on. In Mark III modes the hardware ID is placed in the second most significant byte of the
serial status register.
If the requested sampler track assignments and formatter track enables would imply use of only
odd or even recorder tracks only and the head.ctl control files indicates that only even or
odd tracks are to be used, the sampler assignments and enables are automatically mapped to the
corresponding even or odd tracks. If both odd and even tracks are used and/or the head.ctl
specifies all heads are to be used, no mapping takes place. The Mark III modes prn, a, b, c,
dn assign samplers to and enable all the odd and even tracks required, so no mapping is required
for these modes.
Syntax: form4=command
Response: form/response
Settable parameters:
command any legal command sentence as described in the Mark IV Formatter Vocabulary
manual. The characters \r\n (carriage-return, line-feed) are appended before sending the
command.
Monitor-only parameters:
response response to command. The >\r\n at the end of the response is not included in the
Field System log. For accepted commands, which have only >\r\n as the response, the Field
System logs ack.
Comments:
Refer to the Mark IV Formatter Vocabulary manual for a description of all valid commands and
their syntax.
This command is a simple feed-through to the Mark IV formatter. No checking is done on the
command, no action is taken for any response. This form of the command is temporary while it is
determined what standard parameters are desired.
The command is sent to the MAT bus just as if the operator had used the mat command. No
modifications are made before the command is sent on the bus.
Use this command to set the formatter clock, with the /TI, /TR, /TA commands. After
setting the formatter time, issue a sy=run setcl offset command to reset the Field
System time. The fmset program may also be used to set the formatter time.
Examples:
form4=/ass 0 1:2 3:4 #92/ass 0 1:2 3:4\r\n
Syntax: fsversion
Response: fsversion/version
Monitor-only parameters:
version field system version number.
Comments:
Used to display and log version number of the currently running field system.
Syntax: halt
Response: none
Comments:
This command halts execution of the schedule until a cont command is issued by the operator.
Once the current schedule command is finished, no further commands of any kind will be read
from the schedule command stream while the halt is in effect. Interactive commands from the
operator command stream will still be processed. This is an immediate execution operator
command.
Syntax: hdata
Response: hdata/hd0p,hd1p,hd0t,hd1t,vac,oddpwr,evpwr,ref
Settable parameters: none
Monitor-only parameters:
hd0p Head 0 position.
hd1p Head 1 position
hd0t Head 0 temperature
hd1t Head 1 temperature
vac Vacuum sensor
oddpwr Odd reproduce power
evpwr Even reproduce power
ref Reference voltage
Comments:
MAT module functions available for Mark III. No MCB functions available.
This command reads the Head Positioner A/D channels, all values are reported in units of volts.
Data from all channels are reported regardless of whether anything is hooked up to them or not.
In particular, most stations do not use the temperature channels, the vacuum sensor, and normally
only one of the reproduce power channels is hooked up.
The position voltages (and all others) are reported with the LVDT off. Use the lvdt command
to measure positions with the LVDT on.
All parameters except oddpwr and evpwr are null if the drive type specified in the equip.ctl
control file is vlba2.
Syntax: hdcalc
hdcalc=clear
Response: hdcalc/writeF,readF,writeR,readR,writeS,readS
Settable parameters:
none, however hdcalc=clear will delete previously calculated values
Monitor-only parameters:
writeF Forward absolute offset for the write head
readF Forward absolute offset for the read head, null for VLBA
writeR Reverse relative offset for the write head
readR Reverse relative offset for the read head, null for VLBA
writeS Write head scale
readS Read head scale, null for VLBA
Comments:
This command will calculate new calibration parameters based on the voltages saved with the
savev command. See the Narrow Track Calibration manual for a description of the
calculations. Only one scale factor is calculated for each head.
Any parameters which cannot be calculated because savev has not saved a complete set of
voltages will be reported as null, i.e. empty.
The VLBA recorder has only one head. Its parameters are reported as the write head parameters
and the read head parameters are null.
Syntax: hecho=on/off
Response: hecho/on/off
Settable parameters:
on/off on to turn echo on, off to turn echo off.
Monitor-only parameters: none
Comments:
This command prints debug information for commands that use the head positioner (peak and
locate).
Syntax: help=command
?=command
Response: displays information on the screen
Settable Parameters:
command The name of any SNAP command.
Comments:
This command displays available information on the specified SNAP command. Either the
command help or the question mark ? may be used. Typing help or ? alone gives help on
help. The help information is essentially the listing of the manual page for the SNAP command.
This Field System help command opens a new xterm window and uses the less pager to
display the requested help text one screen-full at a time. At the bottom of the window you will
see a prompt in inverse video that includes the name of the file being displayed (which you can
ignore). If you want to continue the listing, press the space bar and the next screen-full will be
displayed. To exit from the command, type the letter q (not echoed on the screen). For help with
less, type the letter h to the prompt. The full options of less are available including text
searches and scrolling back.
In some cases statistics about where in the file the current screen-full comes from may be
displayed in the prompt. In some cases, less will display only a colon : prompt.
When you see (END) in inverse video in the prompt at the bottom of the screen, you have reached the end of the help information on this topic. Press the letter q to exit. When you press q, the help
xterm window will close automatically. While the text is displayed in the window you can also
use the xterm scroll bar to move around within the text.
The help information is kept in files in the directory /usr2/fs/help, one file per command.
Versions for different configurations are distinguished by the two characters in the file extension
for the type of hardware. The first character is for the type of rack and the second is for the type
of recorder. The characters used are m for Mark III, v for VLBA, 4 for Mark IV, and for any.
The content of the files is the ASCII version of the pages in this manual. Station-dependent help
files are found in /usr2/st/help.
If no help is available for a command, a message to that effect will be displayed in the log output
window. You will also receive this message if you request help for a command that is not defined
for your equipment.
Syntax: hpib=mn,data
Response: hpib/data
Settable parameters:
mn 2-character mnemonic of the module to be addressed, as found in the ibad.ctl control file.
data complete message to be sent to module, if any. Talk-only modules do not accept data.
Monitor-only parameters:
data response of module, if any. Listen-only modules do not generate any response.
Syntax: ifd=atten1,atten2,input1,input2
Response: ifd/atten1,atten2,input1,input2,rem/lcl,TP1,TP2
Settable parameters:
atten1 IF1 attenuator setting in db, range 0 (default) to 63 db. Enter a numerical value preceeded by + or - to indicate relative change. Other options are max, or old to restore the previous value after a max.
atten2 IF2 attenuator setting in db, range 0 (default) to 63 db. Enter a numerical value preceeded by + or - to indicate relative change. Other options are max, or old to restore the previous value after a max.
input1 IF1 input, nor (default) or alt.
input2 IF2 input, nor (default) or alt.
Monitor-only parameters:
rem/lcl switch setting, remote or local
TP1 IF1 total power reading
TP2 IF2 total power reading
Comments:
MAT module functions available.
The max and old values for the attenuator parameters allow the attenuators to set to the
maximum value of 63, and then returned to their previous values.
Syntax: if3=atten,mixer,sw1,sw2,sw3,sw4
Response: if3/atten,mixer,sw1,sw2,sw3,sw4,switch,freq,rem/lcl,
LOlock,TPI
Settable parameters:
atten Attenuation in dB, range 0-63, default 0. Enter an integer value preceded by + or - to indicate a relative change. Other options are: max, or old to restore the previous value after max.
mixer Downconverter in or out of the signal path, default out. In response only: 11 or 00.
sw1 Switch 1 state: output to port 1 (default) or port 2.
sw2 Switch 1 state: output to port 1 (default) or port 2.
sw3 Switch 1 state: output to port 1 (default) or port 2.
sw4 Switch 1 state: output to port 1 (default) or port 2.
Monitor-only parameters:
switch present or missing.
freq Synthesizer frequency in MHz.
rem/lcl Switch setting, rem or lcl
LOlock LO lock/unlock status, lock or unlock
TPI Total power integrator reading, decimal, 0-65535.
Comments:
The max and old values for atten can be used to switch in the maximum attenuation and then
restore the previous (old) attenuation. This is primarily useful for system temperature
measurements. See the sxcts procedure in the Standard Procedure manual for an example.
The mixer state commanded by this command and the down converter frequency specified in the
equip.ctl control file are used by the pcal command to calculate the frequencies of the
phase-cal tones for the video converters that are specified as connected to IF3 with the patch
command. The beam3 command also uses this information to calculate the default beam size.
If the switch for the mixer is an undefined state, the mixer response is 11 or 00 depending on
which incorrect state the mixer is in, see the MAT Protocol manual for details.
The monitor values of the switch settings sw1-sw4 are null (empty) if the equip.ctl file
shows the switch as not connected. Only switches that have been identified as connected can be
commanded. The switch monitor-only parameter indicates whether the switch box itself is
installed.
The external switch settings sw1-sw4 commanded are not used to calculate the patching. The
effect of the switch settings, i.e., which video converters are connected to which inputs, must be
specified in the appropriate patch command.
Unless low-pass filters have been installed in some of the output channels, the IF3 module should
only be used to distribute "high" 170-500 MHz IF frequencies to the video converters.
Syntax: ifdab=attenA,attenB,inputA,inputB,avper
Response: ifdab/attenA,attenB,inputA,inputB,avper,TPA,
TPB,serno,err
Settable Parameters:
attenA Attenuator setting for IF channel A. 0 (default) or 20 db. Normally this attenuator should be set to 0 so that the 20 db can be used for radiometry.
attenB Attenuator setting for IF channel B. 0 (default) or 20 db. Normally this attenuator should be set to 0 so that the 20 db can be used for radiometry.
inputA Input source for IF channel A. nor (default) for normal input, ext for front panel IF input.
inputB Input source for IF channel B. nor (default) for normal input, ext for front panel IF input.
avper Averaging period in seconds for the total power integrator. May be 0, 1, 2, 4, 10, 20,
40, or 60 seconds. A value of 0 results in 1/80 sec averaging time. Default 1. The averaging
period is synchronous with 1 pps.
Monitor-only Parameters:
TPA Total power in IF channel A in counts. Range 0 to 66535, nominal operating level = 16000.
TPB Total power in IF channel B in counts. Range 0 to 65535, nominal operating level = 16000.
serno Module serial number.
err Module timing error indication, 1pps or no 1pps.
Comments:
This command sets up the IF distributor module that is connected to channels A and B. Use the
ifdcd command to set up channels C and D. This command is analagous to the Mark III ifd
command.
MCB module functions are available.
The nominal input level to the rack is -20 dbm. If this level is present then the total power will be
at the nominal value and no extra attenuation will be needed.
Syntax: ifdcd=attenC,attenD,inputC,inputD,avper
Response: ifdcd/attenC,attenD,inputC,inputD,avper,TPC,TPD,serno,err
Settable Parameters:
attenC Attenuator setting for IF channel C. 0 (default) or 20 db. Normally this attenuator should be set to 0 so that the 20 db can be used for radiometry.
attenD Attenuator setting for IF channel D. 0 (default) or 20 db. Normally this attenuator should be set to 0 so that the 20 db can be used for radiometry.
inputC Input source for IF channel C. nor (default) for normal input, ext for front panel IF input.
inputD Input source for IF channel D. nor (default) for normal input, ext for front panel IF input.
avper Averaging period in seconds for the total power integrator. May be 0, 1, 2, 4, 10, 20,
40, or 60 seconds. A value of 0 results in 1/80 sec averaging time. Default 1. The averaging
period is synchronous with 1 pps.
Monitor-only Parameters:
TPC Total power in IF channel C in counts. Range 0 to 66535, nominal operating level = 16000.
TPD Total power in IF channel D in counts. Range 0 to 65535, nominal operating level = 16000.
serno Module serial number.
err Module timing error indication, 1pps or no 1pps.
Comments:
This command sets up the IF distributor module that is connected to channels A and B. Use the
ifdab command to set up channels A and B. This command is analagous to the Mark III ifd
command.
MCB module functions are available.
The nominal input level to the rack is -20 dbm. If this level is present then the total power will be
at the nominal value and no extra attenuation will be needed.
Syntax: label=vsn,check,type
Response: label/vsn,check,type
Settable parameters:
vsn 8 or 10-character tape VSN, e.g. HS001234
check 4-character check-label corresponding to VSN e.g. 8E45. If no check label appears on the tape, run program labck to generate it.
type thick or thin, defaults to type implied by VSN. For monitor this value only appears
until the tape is loaded with a rec=load command. This parameter is not available unless
vacuum switching is enabled in sw.ctl control file.
Comments:
Normally used after newtape command has halted the schedule. There are two different modes
of operation depending on whether the Volume Serial Number (VSN) has 8 or 10 characters.
When the label command is entered directly by the operator, 8-character VSN are used. Tape
number and check label must correspond or execution of schedule will not continue. The effect
of this command is the same as that of cont. Digit zeros (0) and letters Os are both treated as
zeros in both number and check for operator convenience.
The ten-character mode will normally be used only by the rwand programor a bar code reader.
In this mode, the first eight characters of vsn correspond to the tape number, while the tenth
character is used for a barcode checksum. Any other parameters are ignored. A fake, but correct,
check-label code will be generated if the barcode checksum is correct.
For VLBA drives and specially equipped Mark IV drives that use vacuum switching, this
command is used specify whether the thick or thin vacuum level (and for VLBA drives thickness
parameters as well) are commanded. Please see the rec command for more details.
Syntax: label=vsn,type,code
Response: label/vsn,type,code
Settable parameters:
vsn up to 20 character VSN, e.g., CA-1-0012305
type one or six character tape type, e.g., 1, or 010020, may be omitted if code is csa. If not omitted and code is csa, it must agree with the type specified in the vsn.
code tape label format, an arbitrary string up to 32 characters, default is csa.
Comments:
Normally used after newtape command has halted the schedule.
If code is csa, vsn is interpreted as a CSA format, "XX-T-YYYYYZZ-N" label. The "XX-T-YYYYYZZ" part of label uniquely identifies a set of eight tapes. The check-sum in checked. If
type is specified it must agree with the "T" type from the vsn, unless six characters are specified
for type. If type is not specified, the single character "T" from the vsn is used as the type. The
suffix "-N" must be omitted if all eight tapes in a set are loaded, even if they will not all be
recorded as one group. If fewer than eight tapes are loaded, which tapes are inserted and the order
of their insertion in the transports should be specified in the suffix. For example if the first four
tapes in a set are inserted in order the suffix "-0123" should be used. When fewer than eight tapes
are inserted they should be inserted in ascending order and must go into consecutive transports in
ascending order starting with transport 0. Loading the tapes in this way and using the suffix as
described is necessary in order for the correlator to load the tapes for playback based only on
information available in the log. In addition, if the tapes are not inserted in consecutive transports
beginning with transport 0, the schedule will probably fail.
For all other values of code, vsn may be an arbitrary string up to 20 characters long, but type
must be specified in this case.
If the recorder is already recording and a tape type different than what is use is requested, no
change will be made and an error will be reported.
Syntax: list=start,#lines
Response: display of 10 lines of schedule
Settable parameters:
start place in the schedule to begin listing. May be one of the following:
null to start two lines before the line currently being executed
#line, where line is the starting line number, to start at a particular line number in a schedule
time, in standard SNAP time format, to start at the line which has a time equal to or later than time
#lines number of lines to list, default 10
Monitor-only parameters: none
Comments: Ten lines of the current schedule, with line numbers, are listed on the terminal. If the
current executing line of the schedule is included in the range listed, it is identified by a leading
right arrow >. Only the active schedule may be listed with this command. This is a display-only
response - no information is logged.
Syntax: lo=chan1,chan2,chan3
Response: lo/chan1,chan2,chan3
Settable parameters:
chan1 LO frequency for IF channel 1, MHz. Default 0. Normally this is the X-band channel.
chan2 LO frequency for IF channel 2, MHz. Default 0. Normally this is the S-band channel.
chan3 LO frequency for IF channel 3, MHz. Default 0. Normally this is the high end of the X-band channel.
Monitor-only Parameters: none
Comments:
This command specifies the total LO for each Mark III IF channel. If your station has an
upconverter, use the upconv command to specify the frequency. If your station has the IF3
module, the frequency of the IF3 LO from the equip.ctl file and and commanded mixer state
are automatically taken into account, i.e., do not include the effect of IF3 in the LO frequencies.
The LO and upconverter frequencies are used by program pcalr and by the antenna calibration
programs. These values along with the video converter frequencies are used to calculate the
phase calibrator tone frequencies. For Mark III systems, the patch command should also be
used to specify which converters are on each IF channel.
Syntax: lo=chanA,chanB,chanC,chanD
Response: lo/chanA,chanB,chanC,chanD
Settable parameters:
chanA LO frequency for IF channel A, MHz. Default 0. Normally this is the X-band channel.
chanB LO frequency for IF channel B, MHz. Default 0. Normally this is the S-band channel.
chanC LO frequency for IF channel C, MHz. Default 0. Normally this is the high end of the X-band channel.
chanD LO frequency for IF channel D, MHz. Default 0.
Monitor-only Parameters: none
Comments:
This command specifies the total LO for each VLBA channel. If your station has an upconverter,
use the upconv command to specify the frequency.
The LO and upconverter frequencies are used by the antenna calibration programs.
Syntax: locate=range,nsamples,step,stack
locate
Response: locate/range,nsamples,step,stack,peakv,mper,vltlc
Settable parameters:
range range to search over in microns. Default is 200.
nsamples Number of power samples for each measurement position. Default is 1.
step Micron step size between measurement positions. Default is 40.
stack Head stack to move: write or read. 1 and 2 may also be used to mean the write and read
head stacks, respectively. Only the first character is checked. Only write is valid for VLBA
recorders, this is the default. For Mark IV recorders, use write or 1 for head stack 1, read or 2 for
head stack 2. Default is read for Mark III and Mark IV.
Monitor-only parameters:
peakv Peak measured voltage from power detector
mper Minimum sample voltage as a percentage of peakv
vltlc Location of the peak in positioner voltage
Comments:
This command performs a coarse grid search for the largest detected power over the search
range. The search is performed over a range of range microns about the initial head position.
The number of positions sampled is ((2*range)/step)+1.
The actual positions at which measurements are made are not exactly step microns part. The
head stack will be positioned within 5 microns of the nominal positions. This approximation is
used to reduce the time moving the head stacks by not over-refining the positions of what is a
coarse search anyway. In the worst (too coarse) case two positions might be step+10 microns
apart.
After sampling over the complete range, locate returns the head stack to the position that gave
the highest power level, makes a new measurement and reports these values for the peakv,
mper, and vltlc parameters.
This command requires that the reproduce power detector be hooked-up with a reasonable
amount of attenuation and that the head.ctl control file correctly identify which detector (odd
or even) is in use.
This command must be issued once with parameters to set it up. Issuing the command
subsequently without parameters will start a search. The tape must moving and there must be
recorded data to reproduce for this command to do something useful.
See the Narrow Track Calibration manual.
Syntax: log=name
Response: log/name
Settable parameters:
name name of log file to be opened. If no directory path is specified, /log is assumed. If no
extension is specified, .log is assumed.
Monitor-only parameters: none
Comments:
When the Field System is initialized, log file station.log was opened or created in directory
/usr2/log. If the log file requested by this command cannot be opened or created, the Field
System returns to using the log file previously in use. If no log file can be successfully opened,
execution of the schedule continues, but an error message is displayed on the screen every time
an attempt is made to write into the log.
This command is not implemented.
Syntax: logout=file,mode,bits,parity,stop
logout=*,file,mode,bits,parity,stop
Response: logout/file,file,
Settable parameters:
dev File name for display output. This may either be a normal file, e.g., /tmp/logout, a pseudo-terminal device file that is in use as an xterm, e.g., /dev/pts011, or a serial port device file, e.g., /dev/cui1h. No default.
mode Open mode for file, one of append, write, or a valid BAUD rate: 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, or 38400. The default is write. If a BAUD rate is specified it implies that the file being opened is serial device. The remaining parameters may be used to define the line protocol.
bits The number of bits per character transmitted, one of 5, 6, 7, or 8. The default is 8.
parity How parity generation is handled: none, odd, or even. The default is none.
stop The number of stop bits, one of 1 or 2. The default is 1.
Comments:
Log entries are always written into the log file and sent to the display device for the ddout
program. This command can be used to send the displayed output of the ddout program, both
log entries and information messages (including bus communications echoing) to other terminals,
devices, and files. This command is useful for recording the displayed output in a file for later
examination or to direct the output to an auxiliary display.
Up to five different output files (or devices) can be in use at any time. However, only one new
device can be specified per logout= command. If the logout=*, form is used, the
specified file receives the display output in addition to those already doing so. If the form without
the asterisk "*" as the first parameter is used, any files currently in use will be closed and the
specified file will be opened. The command logout= with no parameters will close any files
current receiving output.
The line protocol parameters bits, parity, and stop are useful only if the mode was specified as a
valid BAUD rate. The default mode, write, will cause the specified file to be overwritten if it
already exists.
If a file is not specified as an absolute pathname, i.e., without a leading slash "/", the file will be
opened in the current directory that the Field System was started from, usually /usr2/oper.
Because of the mapping of all command input to lower case, it is not possible to open a file that
contains any upper case letters. This files can still be opened if they are linked to a another file
name that does not contain upper case letters. For example, the file /dev/ttyF01 could be
linked to /dev/ttyf01 using the UNIX command: ln /dev/ttyF01 /dev/ttyf01.
Then /dev/ttyf01 can be used as the file name. Also because of the special meaning of
asterisk "*" as the first parameter it is not possible to open a file with a name of asterisk unless
the logout=*, command form is used.
Files are opened with the permissions of the user that started the Field System, usually oper.
Syntax: lvdt=cmdVw,cmdVr
Response: lvdt/cmdVw,cmdVr,actVw,actVr,deltaVw,deltaVr
Settable parameters:
cmdVw Command position voltage for the write head stack, default is don't move. For Mark IV this parameter refers to head stack 1.
cmdVr Command position voltage for read head stack, default is don't move. Th