DH Instruments PPC3 - Pressure Control Module; Display; Driver Board; Pneumatic Schematics

5. MAINTENANCE, ADJUSTMENTS AND CALIBRATION
Page 137 © 2002-2007 DH Instruments, a Fluke Company
5.8.6 PRESSURE CONTROL MODULE
The pressure control module is an integrated assembly that includes two inlet (fast and slow);
two exhaust (fast and slow) control valves; vent valve and differential pressure regulators.
The differential pressure regulators use pressure feedback to maintain a constant differential
pressure across the control valves. The control valves are solenoid type, actuated by 12 V.
See Figure 13 for the pneumatic module schematic.
5.8.7 DISPLAY
2 x 20 character vacuum fluorescent display.
5.8.8 DRIVER BOARD
The driver board is controlled by the micro card (see Section 5.8.5). It supports:
• 12 V drivers for internal and external solenoid valve actuation
• Frequency counters (2) for Q-RPTs (see Section 5.8.6.1)
• On-board barometer power and output (see Section 5.8.4)
• Vacuum sensor power and output for ControlRef function (see Section
3.5.7.2)
• Utility sensor power and output
• Power to the system cooling fan
• Remote [ENT]
• Keypad and display
• Beeper
5.9 PNEUMATIC SCHEMATICS
5.9.1 PRESSURE CONTROL MODULE
The bypass vent valve is not included in model PPC3-10M.
Figure 12. Pressure Control Module Schematic