Sheila, Nutsinee, Kiwamu,

For some reason, the 2nd loop ISS was not able to converge the PID loop at all during the engagement step. In the end, we engaged it by hand.

We will take a close look tomorrow during the maintenance period, but for the night, we will leave it as it is without any fix.

Instruction for manual engagement

Here is an instruction for the operators if the ISS runs into  a difficulty in engaging the 2nd loop:

• If ISS does not engage the 2nd loop for more than 5 minutes in the "ENGAGE_ISS_2ND_LOOP" state, please proceed to the following steps.
• Check the IMC guardian state.
  • If it has fallen back to 'LOCKED' or something equivalent, re-request ''ISS_ON" manually.
  • Make sure that the IMC_LOCK guardian is in the "PREPARE_ISS" state.
• Open up the medm window for the 2nd loop (SITEMAP --> PSL ---> ISS --> SECOND LOOP).
  • Getting to the 2nd loop medm from the generic ISS medm can be tricky for some people, so see the 1st attachment to check where to click.
• In the 2nd loop medm, check how the output is converging. See the 2nd attached.
  • If the output value is bigger than +/- 5 and does not move, please call an expert.
  • If the output value is moving (or often oscillating), then you can manually turn on the loop by pressing a green "ON" button at the top as shown in the 2nd attached screenshot. A rule of thomb is to click the "ON" button when the output value is close to zero.
• After the manual engagement, make sure that the output value becomes smaller, ideally close to zero without any oscillations.
  • Then the guardian will wait for 60 seconds and automatically move onto the "CLOSE_ISS" state. We are done. It is going to automatically take you to the "ISS_ON".
• If the above does not work or break the lock, please call an expert.

Software seem to be unchanged

Looking at the guardian and foton file, we confirmed that there was no change since Sep 9th. So we think this is not due to a softaware change or some sort. It could be some kind of hardware issues, but because of the fact that it runs OK once engaged, probably the hardware is not completely broken either.