Tiedowns

28jul03

Monitoring:

Failure and modifications log

hardware:

Software


Misc:

Debugging


Description of specific events

01dec17: calibrate load cells after new ldcells installed. Ldcell 2 gain off for all  tds.
25aug17: td 4 jack replaced
03dec13: td4 erratic motion (dac bad?)
02may13: tiedown tensions for apr13. When do the tiedowns lose tension..
02mar13: tiedown 4  position jumps to 24 inches
19may12: td8 releases by itself.
23apr12: td 12 jack replaced. Used bar to reset encoder. Adjusted limits.
19apr12: td12 needs large torques to move. Makes loud noises. Jack replaced.
20feb12: td4 tmscouter time drifting.
10feb12: Changed a/d signal conditioning spdMonitor resistor from 46.2K to 22K.
02feb12: Move td's, measure voltagage, and then compare readback values.
25jan12: commanded and amplifier readback speed mismatch.
27,29oct11: td 4 makes loud noise.
10mar10: tiedown tensions vs az,za,and temp
22feb10: fit tiedown tensions 2008 thru 2009.
10feb10: tiedown tensions during the 12jan10 haitian earthquake.
05feb10: dynamic loading of td's from telescope motion
29may08: tiedown positions during the painting project.
07apr08: td8 stops moving.
28jan08: Check the torque in td12 after adjusting current limit.
16jan08: td12 stops because it doesn't have enough torque to move.
07dec07:equalizing the td positions after removing the lead in the platform corners.
16mar06: td12 does not always start when it is requested to.
02mar06: td12 releases because of bad enc reading.
02sep05: td tensions after loadcells calibrated.
25jun05: td12 releases after lightning strikes td12.
03feb05: td12 moves erratically then goes into fold back.
15nov04: td4. power supply short, motor overspeed.


Hardware:

Schematics:

page
description
0
ctrl cabinet layout
1
breakers
2
ladder logic
3
watchdog
4
brakes
5
ldCells,load metering,autorelease
6
fans
7
little start computer
8
pcu
9
grounding
com
communications
mot
motor installation
dio_1
dio_2
digital i/o boards

Hagen's tiedown  memos:



Fiber optic xmter/rcvr for 1 second tick


Fiber optic xmit/rcvr for 1 sec tick (.pdf)

Motor personality cards


Software

Little star Software:



Tiedown power supply startup sequence:   (top)

The tie motor power supply will provide 3 phase power to the motor if:
  1. the safety is closed.
  2. the master contactor is closed.
  3. there are no power supply faults.
  4. you have requested the tiedowns to move.
The little star uses a two step startup sequence driving 24 volts through:
  1. POWER1 to energize the master contactor relay to startup
  2. POWER2 to drive the master contactor relay during normal operation inline with the power supply fault contactor and the safety.
The normal sequence is:
  1. reset will close the safety if there are no safety problems (eg.blk liftoff, emg stop, etc.).
  2. You must command the tiedowns to move (it can be to the current position) or use the pcu to turn the drives on.
  3. The little star will driver 24 volts through POWER1  dio2 pin 2,3 for about 300 milliseconds. This provides power to the master contacter relay PS_MC_R if the saftey is closed.
  4. PS_MC_R closes the master contactor and the 3 phase power is supplied to the power supply. The power supply will then close the power supply fault contactor (PSR_4_FAULT* goes high). 24 volts is wired through the power supply fault contactor, throught the POWER2 contactor in the little star, the safety, and then the PS_MC_R.
  5. The little star loops up to 20 times checking to see if PSR4_FAULT* goes high (about 100ms/loop i think). This is pin DIO1 J3 pin4 --> lsPin03.  If after 20 times through the loop the contactor hasn't closed, then the little star will drive POWER1 to 0, open POWER2 and log fault 12 (PSR_FAULT psr4F).

Once the little star sees PSR4_FAULT* go high, it turns on (closes) POWER2. After one cycle it will drive POWER1. The PW_MC_R is now getting 24 volts through pwrsupply fault contactor, POWER2 and  the safety contact. If any of these go away, then PS_MC_R  will lose its 24 volts  and the master contactor will open (removing the 3 phase power to the power supply).
    Note: the turret code uses: POWER_OFF=POWER_1, POWER_ON= POWER_2. looks like i changed them for the tiedown code..
I was frustrated having POWER_OFF be one of the signals being driven during the power_on sequence..


Tiedown reference position:

    The tiedown reference position is a combination of the value in ~phil/vw/tdAutoTrk.h and the offsets in the tcl routines tietrk.proc and tiepos.proc. The Reference position is usually for a temperature of 70F.
date
tieRefUsed [td12,4,8]
tdAutoTrk.h
Offsets
Notes
07apr07
14.9276,15.4311,12.3753
14.875,14.616,13.243 .05257,.81511,-.8677
lead from corners, laser shack removed. Painting project weight on platform.
06dec07
15.1140,15.7028,11.9171 14.875,14.616,13.243 .2390,1.0868,-1.3259
after 06dec07 tilt run. Painting project weight off platform.
09dec07
15.1140,15.2028,15.1670 14.875,14.616,13.243
.2390,.5868,1.9241
After td nuts moved to equalize td positions.
10dec07
15.0718,15.3196,15.0926
14.875,14.616,13.243
.1968,.7036,1.8496
Updated using the first two aswings done on 10dec07.


 Pictures of tiedown system:



debugging:

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