8:15a start. Confirmed with Operator that IMC is offline, so no light's on the DCPDs. 8:15 - 8:30a Set up measurement electronics, installed S2300002. - S2300002 is now in U26. - (S2300003 remains in U24 for now.) 8:30 Powered ON S2300002 (with only DC power cable connected in the back, for now) 8:31 - 8:32 powered down TIA, disconnected cable ISC_307 from S2300003 and connected to S2300002. 8:32-8:40 Cable changes from S2300003 to S2300002 (all low voltage >5 V, and BIO requests are OFF, so OK to do with whitening chassis powered on). - Swapped ADC read back DB9, - swapped Bias read back DB9, - Swapped BIO read back and control cable. Connected DB9 breakout to DAC input, rather than swapping over that ISC_444 cable just yet. 8:40 - 8:45 starting documentation to give the TIA's a chance to recover from the brief power outage. Physical setup Measuring transimpedance amplifier by itself. [1] Actual Board S/N SN 02 [2] In-vac "QPD" Enclosure S/N S2100832 [3] Transimpedance Circuit Schematic D2000592 Measuring using [4] D2200215 OMC Whitening Chassis S/N S2300002 [5] D1900068 SR785 Accessory Box S/N S1900266 Following measurement setup defined in /ligo/svncommon/CalSVN/aligocalibration/trunk/Common/Documents/D1900027_CalElectronicsMeasurementDrawings/ D1900027-v5_aPLUSO4_D2200215-v1_OMCDCPDTransImpAmp_TransImpAmpSetup.pdf Connecting accessory box SR785 differential drive BNCs to clip-doodles to DB9 breakout pins 1(pos)-6(neg) (with shield connected to chassis GND pin 5), into "From AI/DAC" DB9 port IN THE BACK of the D2200215 chassis. Be mindful that the BNC back-shells / shields are not touching anything metal, like the rack or chassis as they're fed from the CH1 A & B DUT output of the accessory box through the rack to the AI/DAC input. Connecting SR785 response comes from the "preamp output monitor" BNC spigots at the front of the D2200215 chassis, "A+" to CH2 A "A-" to CH2 B. OK, let's get this right. Disconnect SR785 SOURCE from Accessory Box. Factory Reset the SR785. System Preset Display Setup TOP TRACE Measure Group: Swept Sine Measurement: Freq. Resp View: Linear (Magnitude, i.e. not in dB) Units: dB Units: OFF Pk. Units: OFF Phase Units: deg dBm. ref impedance: 50 BOTTOM TRACE Measure Group: Swept Sine Measurement: Freq. Resp View: Phase Units: dB Units: OFF Pk. Units: OFF Phase Units: deg dBm Ref. Impedance: 50 Freq Start: 102.4 kHz Stop: -- 10 Hz Starting for Setup & Confirmation of expected response -- 0.1 Hz Final version of Measurement Repeat: Single Shot (don't continuously repeat sweep once done) Type: Log (log-spaced frequency vector) # of points: 200 Auto Res.: OFF Display Options [Both] Display: Live Format: Dual RPM Frequency: OFF Grid: ON Grid Div: 10 Phase Suppress: 0.0e+00 d/dx window (%): 0.5 Source Auto Level Ref: OFF Amplitude: 4.0 V_pk << This is key for good low-frequency data! Source Ramp Rate 1 V/sec, but Source Ramping OFF Offset 0.0 V Input Setup DON'T FORGET :: Auto Offset OFF Input Source: Analog Input Config: CH 1 (Both Channels) Mode: A-B (positive legs into A, negative legs into B) Coupling: DC (AC coupling filter is at 0.16 Hz, and we're measuring to 0.1 Hz, so we don't want to be impacted by the response of this filter.) AA filter ON Wt filter OFF Autorange UP ONLY Input Range (for 4.0 V source amplitude, 50 ms / 5 cycle integration): CH1: +14 dBVpk CH2: +16 dBVpk Input Range (for 1.0 V source amplitude, 50 ms / 5 cycle integration): CH1: +2 dBVpk CH2: +4 dBVpk DON'T FORGET :: Auto Offset OFF Transducer Params: (all as default; unused in this style of measurement) Tach Input: (all as default; unused in this style of measurement) Playback Config: (all as default; unused in this style of measurement) DON'T FORGET :: Auto Offset OFF Average Setup Settle Time = 250 ms (250 ms) << increased from 100 ms, based on analysis of impulse response Settle Cycles = 2 << increased from 1 Integration Time = 250 ms (250 ms) << increased from 100 ms, based on analysis of impulse response Integration Cycles = 7 << increased from 5 to get better low-frequency data. with freq = [0.1 102.4e3] and 200 points, this takes 1.4 kseconds = 23.33 minutes (up from 15.24 minutes, mostly because of the 2 settle cycles instead of 1.) New crossover frequency is lower 14.95 Hz rather than 29.96 Hz Hopefully this helps with the noise at the ~25 Hz resonance. Output Hard Copy Button ASCII Dump Bitmap Printer PC X 8 Bit Bitmap Area Graphs Vector / Plotter PostScript (doesn't matter, unused) Destination Disk File File Start Number 0 RECONNECT SR785 source to Accessory Box cable. Make sure "Preamp Test Input Relays" are turned ON Diagram shows / says that both can be on during the measurement of each. While I agree it shouldn't matter, since the A and B circuits are different / separate, today it gives me bad joy joy vibes, so start with only DCPD test relay ON. 9:00a ran a quick check with Freq Start: 102.4 kHz Stop: -- 1 Hz Starting for Setup & Confirmation of expected response Repeat: Single Shot (don't continuously repeat sweep once done) Type: Log (log-spaced frequency vector) # of points: 50 Auto Res.: OFF to check that I've got the phase right. I didn't -- 180 deg flipped from past results. Biffed the Accessory box to DAC Input clip doodle sign, deceived back cable tags. Flipped the Pin 1 & Pin 6 connection. This is why we do it! Ran test frequency vector set up again, and phase that matches expectation. Switching frequency vector back to final measurement configuration. Freq Start: 102.4 kHz Stop: 0.1 Hz Repeat: Single Shot (don't continuously repeat sweep once done) Type: Log (log-spaced frequency vector) # of points: 200 Auto Res.: OFF 9:05a started DCPDA measurement! 1.4 ks / 23.3 minutes. 9:27a done. Exported data for check. Noise looks great. Data very clean down to ~1 Hz. Response is not flat w.r.t. the previous model from 20240423 data run tho... And the measurement in GW band is 2 V/V rather than 1 V/V... 9:30-9:33 switched over cabling to DCPDB, then turned OFF preamp A test relay input, and turned ON preamp B test relay input. 9:33a started DCPDB measurement While we confirming the setup to investigate 2 V/V, accidentally changed the Input CH1 Input Mode from A-B to A. CRAP. 9:42a Restarted DCPD B (again with only preamp B test relay input.) See that the data is still 2 V/V in GW band. Test out "bad joojoo" and turned on both preamp test inputs. No change, still 2 V/V. Decided to stick with having the opposite channel OFF. Here's hoping the the measurement setup has a factor of 2 V/V. Maybe on leg of the the accessory box is hosed or something? 9;45a Restarted DCPD B (again with only preamp B test relay input.) 10:09a measurement done. Exporting... 10:10-10:12a switching to "measurement setup" configuration - Turn OFF preamp test input relays - Power off TIA preamps - Disconnect preamp cable, ISC_307 from "Preamp Chamber Interface" DB25 port in front of chassis - Connect DB25 breadboard in its place "Preamp Chamber Interface" - Disconnect drive DB9 breakout input from DB9 plugged into DAC output, bring cable collection to the front. - Change those drive clip leads from DB9 breakout to DB25 breakout, connecting CHA 5 & 18, w/ GND/Shields connected to 13 - Move preamp monitor BNC readout cables over to A+ and A- 10:13a started measurement setup. YUP. The measurement setup has this factor of 2. Ans some frequency response! AAAHHHHH REAL MONSTERS!!! Gain at 100 Hz is 1.999 V/V, and gain at 40 kHz is 2.186. AAAHHHHH 10:35a measurement done. Exported data looks indeed quite crazy. Tried swapping out the Accessory box for S1900276. and remeasured DCPDA, only changing BNC setup at the SR785. (Didn't save the data, but) using the "display ref" I see that the data is the same non-sense. Carrying on ... Switching back to Accessory box S1900266, and switching over to DCPDB. 10:48a start. 11:05a DCPBB measurement setup done. Switching measurement setup back to S2300003, to see if that's still wonky and/or the same as today's wonky. 11:07a start. YUP. SAME AS S2300002 gain of 2.0 and frequency dependent. What the heck is going on?! Letting this data run its course so that I can prove to folks that I'm not insane. 11:29a measurement done. 11:30a preamps powered back on Things to do after we get this measurement suite: - Send the data to Louis for fitting. - Create/install new AntiW filters for A0 / B0 bank - Create/install new V2A filters for A0 / B0 bank - Switch over to these filters and accept in SDF - Run dark offsets for DCPDs -- do we need to? - Update pydarm parameter file with new super-Nyquist poles and zeros. - Measure compensation performance with remote DAC driven measurement of TIA*Wh*AntiWh*V2A confirm bitterness / flatness make sure binary IO still functions When to push new calibration? Once IFO is back up, running, (does it need to be thermalized?) - Measure balance matrix, Remember -- SQZ OFF confirm better-ness / flatness - Install new balance matrix - Accept Balance Matrix in SDF Once IFO is thermalized - grab a new sensing function.