Gabriele, Sudarshan

We were able to close and open the ISS Second Loop with attached python script.

Some details about the script:

• Initially, it makes sure the loop is open, integrator and boost are off, gain is at 0dB and second loop servo is on.
• It sets the ref signal value so that it is not too far away from the nominal value; this value is determined by looking at the average in loop PD value. 
• It then calculates the average of second loop output and compares it to the user defined  threshold to move the ref level signal such that the second loop output is less than the threshold.
• After that, it waits for second loop signal to be around zero crossing to switch on the second loop. This was done because the timing of switching-on the second loop mattered. If the second loop output value was far off from zero, it threw the mode cleaner out of lock.
• At the end it checks if the ref signal is within the threshold. If it is, the boost and integrator are turned on and the loop remains closed, if not, the loop opens.

These python script will be eventually implemented on the IMC Guardian.

Note: We tested it 10 times in a row  and it never failed.