Continued to klog31222, klog30105
I connected a BNC cable from BNC#4 of the Dsub-BNC converter (S1605874) at U25 of ALS1 rack to the injection box which is connected to CARM-CMS EXC port so that we can excite CARM with DGS. The function seems to work well.
## procedure
- BNC#4 and BNC#5 of the Dsub-BNC converter (S1605874) at U25 of ALS1 rack seems to be already connected to FIB X/Y EXC (fig.1). Accoriding to Yamamoto-san, this connections are not used now. So I disconnected them from BNC#4 and BNC#5.
- I connected a cable from BNC#4 to Moku ch1 directly ro confirm that the connection in RT model was correct. Fig. 2 shows the timeseries of the signal from BNC#4 just after the connection. I found DAC has a DC offset, 5 mV. Then, I injected the excitation from K1:LSC-CARM_SERVO_EXC_A_CALI_EXC. According to FM10 in the EXC_A_CALI filterbank, the excitation unit is calibration to V. Also, according to FM10 in the bank, the excitation output gets 0.025 times smaller (fig.3). So I injected the sine wave with 1 V at 100 Hz, (the setup is in fig.4) then I measured the ouput. Fig.5 show the result. the ouput seems to be ~24 mV. it seems to be consistent with the calculation (1V*0.025 = 25 mV). So it seems to be fine.
- After that, I connected the cable from BNC#4 to the empty port of the injection box which was prepared previously in klog30105. The injection box seems to decrease the excitation amplitude to half according the circuit written back the box. Also, the excitaion port of CARM_CMS decreases the excitaion amplitude 1/10 smaller according to the CMS circuit (JGWdoc). So if we inject 20 V from the EXC_A_CALI_EXC ch, the input excitaion amplitude to CMS main path become 20V*0.025*0.5*0.1 = 25 mV. I injected the sine wave with 20 V at 100 Hz from EXC_A_CALI_EXC and measured the input excitation by the TEST2 port of CARM_CMS (the setup is in fig.6). Fig.7 shows the result. The measured amplitude seems to ~23 mV at 100 Hz. It seems to be fine. Consequitly, the digtal injection to CARM seems to be ready.
- [Note]: Fig. 8 is the timeseries of the signal from TEST2 without the excitation. This DC offset value (~65mV) is the same as K1:LSC-CARM_SERVO_SUM_MON_OUTMON so it came from the upstream from TEST2. Therefore, I turned on AC coupling at the Fig.5 measurement time.
