LIGO Document D1002529-v5
- The Ring Heater Driver is a constant current source. Its current can be set by two DAC inputs. One input is highly filtered and the other has a wide bandwidth.
The driver gives a differential voltage proportional to the current to the ring heater (ammeter). It gives a differential voltage proportional to the voltage across the the Ring Heater (voltmeter). Both have whitening filters.
The Driver also provides a voltage proportional to the resistance of a RTD located on the Ring Heater (temperature Sensor) and finally differential voltage proportional to the voltage across the Ring Heater at the PCB.
- -v5 corresponds to the second production lot, which is to be installed everywhere but the H2 chambers BSC 6 & 8
R43 was changed from 1K to 2K. R8 was changed from 15K to 30K. Both changes were made to to accommodate the input range of the Beckhoff ADCs.
The schematic changed the input voltage from +/- 24 Volts to +/- 18 Volts. This lower voltage will allow the drives to operate much cooler.
DCC Version 3.4.0, contact