Digitel MPC Manual
Page 43 of 72
Analog Outputs
Two analog outputs (voltage and current/pressure) from each high voltage (HV) supply are
provided at
J104 SET PT ANALOG OUT
, a 37-pin SUB-D connector on the rear panel of the
DIGITEL MPC.
Voltage measuring
HV supply outputs 1 and 2 provide 0 to 10 volt signals with a scale factor of 1V/1000V output
voltage. To obtain ion pump voltage, measure voltage at
J104
located on the rear panel of the
DIGITEL MPC. Use the following table.
HV Supply Outputs 1 and 2
Measure Pins
Output
Scale Factor
+30, 29 (Gnd) at
J104
HV Supply 1
1V/1000V
+36, 35 (Gnd) at
J104
HV Supply 2
1V/1000V
Current measuring
Analog current/pressure outputs 1 and 2 are computer controlled for maximum flexibility. These
outputs provide signals that are proportional to pump current or pressure. The computer allows
selection of eight output modes via the front panel keypad (PREFERENCES menu) or through
serial port commands. Jumpers on the internal CPU board assembly allow selecting positive or
negative outputs. Connector
J13
configures current/pressure analog output 1 and connector
J8
configures output 2. Jumper pins 3 to 4 and 5 to 6 for positive output or 1 to 2 and 4 to 6 for
negative output. The following tables summarize these outputs.
Current and Pressure Outputs 1 and 2
Measure Pins
Output
+32, 31 (Gnd) at
J104
Supply 1
+34, 33 (Gnd) at
J104
Supply 2
Analog Current Output Modes
Mode
Range
Scale Factor
Press Log
1E-4 – 1E-10
Logarithmic
Volts out = log(pressure) + 10.0V
Curr Log
0 – 1 Amp
Logarithmic
Volts out = log(current) + 8.0V
Curr 1uA
0 – 10uA
1uA per Volt
Curr 10uA
0 – 100uA
10uA per Volt
Curr 100uA
0 – 1mA
100uA per Volt
Curr 1mA
0 – 10mA
1mA per Volt
Curr 10mA
0 – 100mA
10mA per Volt
Curr 50mA
0 – 500mA
50mA per Volt
Note: All modes are 0 – 10Vdc out.
Note: Pressure units are the same as selected for the display.
