Turret not arriving on position

19Feb17


Intro
procedure to change the turret dac zero velocity offset
160112: turret not arriving on position
170219: turret not arriving on position
180529: may18 turret data shows zeroVelErr comes  from dac/signal conditioning board.


Intro

    We have had problems with the turret timing out waiting to be on position. The turret positioning sequences is:

When cima sets up a receiver:

If the turret times out, cima log file has:
2017-Feb-19 03:16:12 LOG4    got_cormsg: From DATATAKING: waiting for turret position:26.64
2017-Feb-19 03:16:53 ERROR   end_wait_seconds: ERROR timed out while waiting for configuring IF/LO path!
2017-Feb-19 03:16:53 LOG1    task_failed: Task 'waiting on configuring IF/LO path' failed!


When timeouts occur, they have been traced to the zero velocity offset of the turret dac, It drifts over time until it is outside the allowable region. This drift can take  days.. So we need to monitor this value daily.. and update the dac before it gets too far out..


12jan16: turret not arriving on position.

     On 12jan16 the turret failed to arrive on position. The final position  was greater than .1 degrees from the requested position.

    This is a similar to problems we had back in aug14. At that time i thought the problem  was from the backlash board being misadjusted.. but  it turned out to be a problem with the zero velocity offset of the dac that drives the motor amplifier (in velocity mode).

    To find out when this problem started i went back through the turret log files and plotted the turret position and the different (actual - requested turret position):

Summary:

processing: x101/160112/turerryr.pro, turerryrmon.pro


170219 turret not arriving on position.

    Timeline of the problem:

The plots shows the turret position and the (Actual - requested) position for Feb 1 to 19 2017. (.ps) (.pdf)

We should monitor this error. When it starts to increase, the zero velocity offset should be recomputed.

processing: x101/170219/turerryrmon.pro


180529: may18 data shows zeroVelErr from dac/signalCond board

    We've had a problem with the turret not arriving at the final requested position (for the last few years). Debugging showed that this occurred when the zero velocity offset for the dac had drifted. This has been occurring more regularly. During 2018 the zero velocity offset had to be updated on:

    The turret data for 01may18 - 29may18 was used to look into this problem.

What happens when commanding the turret to move:


Plotting the may18 turret data

(Warning.. the .pdf files are 1-2MBytes. they may take 10-20 secs to load.)


Velocity command vs velocity feed back, Master amp speed  vs velocity feedback (.pdf)

Velocity command for 0 vel vs date (.pdf)

Checking the +24Volts power supply (.pdf)
Plotting values vs encoder velocity (.pdf)

SUMMARY:

processing: x101/180516/turdac.pro


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