I also would like to extend this script to use the DC readout, but don't know how to calculate the postion offset for AS_DC because the error signal is not zero-crossing for AS_DC anymore. Do you have any suggestions for me?
I don't think I understand the question. AS_DC should not have a zero crossing, correct?
That's right. I calculate the offset of the operation point (when you have RAM) from the zero-crossing point of the PDH signals. I don't know how to do that for AS_DC, because it doesn't cross zero anymore anytime.