R Crouch, R Kumar
CIT (Camille Makarem) shipped us a spare ZM5 PSAMS (s/n 03 with 72 in-lbs pre-load on the mirror for ROC 4.35m) for replacing the broken (strain gauge) PSAMS unit currently installed on ZM5 suspension in HAM7 chamber. We took the new unit out of the shipping container - see attachment01 , attachment02 and attachment03 for reference.
We inspected the optic housing and optic and found no issues with it, posting two pictures for reference - attachment04 and attachment05.
This new unit was then plugged into the electronics chain of ZM5 PSAMS in HAM7 chamber (the suspension was pulled out of chamber and kept on a bench outside HAM7) - see attachment07 and attachment08 for reference.
At first we checked the strain gauge resistance and the results are as follows,
Pin 12 & 24 = 708 Ohms (looks good)
Pin 11 & 24 = 355.9 Ohms (looks good)
Next we varied the PZT voltage from 0 - 200V and measured the Strain Gauge (SG) voltage and the results are posted in the table below,
| Voltage Calibrator Setting (Voltage) | PZT (Voltage) | Strain Gauge (Voltage) |
| +10 | 0.5 | 2.642 |
| +9 | 10.35 | 2.905 |
| +8 | 20.32 | 3.095 |
| +7 | 30.29 | 3.32 |
| +6 | 40.27 | 3.60 |
| +5 | 50.24 | 3.90 |
| +4 | 60.72 | 4.08 |
| +3 | 70.2 | 4.38 |
| +2 | 80.1 | 4.65 |
| +1 | 90.1 | 4.94 |
| 0 | 100.1 | 5.32 |
| -1 | 110 | 6.32 |
| -2 | 120 | 6.50 |
| -3 | 130 | 6.69 |
| -4 | 140 | 6.90 |
| -5 | 149.8 | 7.11 |
| -6 | 159.8 | 7.35 |
| -7 | 169.7 | 7.58 |
| -8 | 179.7 | 8.02 |
| -9 | 189.6 | 8.17 |
| -10 | 194.9 | 8.35 |
The above test tells us the this replacement unit is healthy and can be installed in ZM5 suspension for HAM7 work.
reference - E2100371-v1 (Testing Procedure for PSAMS Strain Gauge Readout)