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fabian.arellano - 20:51 Wednesday 25 November 2020 (15530) Print this report
Top Filter stepper motor limit switches installation.

With Hirata, Satou and Aso.

See pictures, including pictures of the notebook,  at SRM Remedying Work album.

F0 vertical FR motor

  • Hirata-san crimped pins to the cables of the limit switches
  • We removed the limit switches from their supporting frame and brought them underneath the IP table where the D-sub 9 connector is, and inserted the pins in the connector. See the pin assignment in this picture in Google Photos.
  • We tested the pin assignment of the switches by looking at the output of each switch on the medm screen (same as in the picture in the previous item):
    • Upper switch: R for right in the driver naming convention, brown cable to pin 4, blue cable to pin 9.
    • Lower switch: L for left in the driver naming convention, brown cable to pin 3, blue cable to pin 8.
  • We also tested the polarity of the motor: a positive number of steps moved the carriage up; this is opposite to what I had measured before and reported in klog 15272; we need to double check.
  • We put the D-sub 9 connector back to its holder once we decided we didn't want to change the place of the pins.

F0 yaw stepper motor

  • This work was done by replacing the existing motor assembly without the limit switches with one with the limit switches.
  • We weight of the assembly with the limit swtiches is 754 grams.
  • We weight of the assembly without the limit swtiches is 653 grams (measured after removal).
  • Before removing the old assembly we fixed the yaw position of the suspension with cable ties. See pictures for details.
  • In  order to keep same yaw position of the suspension upon motor replacement, in the old motor we measured  the length of the shaft sticking out from a reference surface and we set the same length in the new motor assembly. See pictures of the notebook for details.
  • The pin assegnment was  tested with the medm screen and goes like this:
    • Switch at the shaft side:  R for right in driver naming convention,  brown cable to pin 4, blue cable to pin 9.
    • Switch at the motor side: L for left in driver naming convention, brown cable to pin 3, blue cable to pin 8.
    • See a drawing in a photo of the notebook.
  • We wanted the motor to actuate in positive yaw with a positive number of steps (clockwise rotation of the shaft seen from the shaft side) and achieving this required changing the polarity of the motor via pin reassignment:
    • Before: Green to pin 1, gray to pin 6.
    • After: Green to pin 6, gray to pin 1.
  • We removed 108 grams of ballast mass to compensate for the 101 grams we added with the new motor assembly. There's an extra 7 grams.
Comments to this report:
satoru.ikeda - 9:54 Thursday 26 November 2020 (15534) Print this report
>F0 vertical FR motor
> We also tested the polarity of the motor: a positive number of steps moved the carriage up; this is opposite to what I had measured before and reported in klog 15272; we need to double check.

We reflected the polarity described in "klog 15272;" to the Python code.
This is the result of matching the polarity to the LVDT signal for "offload".
Therefore, we believe that the motor has moved in a different direction than last time.
However, it was very confusing at the time of installation, so once the polarity was changed back to "klog 15272;" then.
Please perform a restart of the Python script.
fabian.arellano - 21:29 Tuesday 01 December 2020 (15571) Print this report

With Hirata, Yano, Iguchi.

See pictures, including pictures of the notebook,  at SRM Remedying Work album.

  • We received new long M3 screws, tall M3 nuts and small M3 washers to install the support for the F0 FR limit switches.
  • Hirata-san washed them in the morning.
  • About installation:
    • The new screws are inserted from underneath the IP table, hold the cable clamps base underneath the IP and the limit switch support on the top.
    • After installation we clamped back some cables we had unclamped to have access for the screws.
  • We tested the limit switches by moving the carriage of the FR and letting the trigger plate mounted in the carriage press the swtich.
    • The plate triggers the lower switch without problems. (We didn't test the upper one).
    • However, the medm required manually updating the stepper motor information to show the switch had been pressed. This is likely related to the polarity of the motor, which we have not changed yet.
  • Following Satou-san's instructions we swapped the switches in the F0 yaw motor. The new cabling diagram can be found in this picture of the notebook.

TO DO list

  • Change the polarity of the F0 FR stepper motor. Find out and report here which pins to exchange. We'll use this information more than once.
  • Check whether we can change the speed of the motor from Ikeda-san's medm screen and increase the speed. Otherwise use Shoda-san's medm screen.
  • Test the whole range of the motor with the limit switches.
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