This is a low level sanity check and a part of the recent delay study (e.g. 29259). I have measured a transfer function between DARM2_OUT and SUS-ETMY_L3_ISCINF_IN1 using dtt while the interferometer was locked last night. The measurement agrees with 1 cycle user model delay (=61 usec). See the attached.
Here is another low level sanity check. The attached shows a tranfer function of signals from the SUSETMY user model to its associated IOP model. It shows a 1 user model clock delay (61 usec) as expected. There is a large deviation above 7 kHz which I don't know why. The FIR filter (T1600454) was included in my 'expected' model.