Now that we're back in low noise, I tried to inject multiple sine waves into DARM using the PCAL to get a sensing function measurement.  

Using the result from alog 52526, I injected five sine waves spaced by factors of 3, starting with 5.62 Hz, to reduce the crest factor to avoid saturating the pcal.
The pcal saturates when the laser is amplitude modulating its full 2 W, basically when the orange line in the ndscopes posted below hits 0 at some crest.  
By injecting at factors of 3 in frequency spacing, and lowering the amplitudes of some of the injected lines to mirror the shape of DARM, I was able to get five going at once, with good coherence (PDFs attached). 


The following should work in any CDS computer ipython terminal 

import sys
sys.path.append('/ligo/home/craig.cahillane/Git/IFO/general/scripts/')
from dataUtils import *
freqs = np.array([   5.62,   16.86,   50.58,  151.74,  455.22])
amps = np.array([30000.,   5000.,   2500.,    573.,  16511.])
phases = np.zeros_like(freqs)
offsets = np.zeros_like(freqs)
exc_channel = 'H1:CAL-PCALY_SWEPT_SINE_EXC'
my_inj = SineMultiple(exc_channel, amps, freqs, phases, offsets)
my_inj.start() # only run if you actually want to inject the sine waves!
my_inj.stop()  # should ramp in 3 seconds