User manual DHI REPLACING PPCH AND PPCH-G VALVE DRIVE BOARD PN 401875 INSTRUCTION SHEET

[. . . ] Replacing PPCH and PPCH-G Valve Driver Board P/N 401875 Instruction Sheet INTRODUCTION In August, 2006 the PPCH and PPCH-G valve driver board p/n 401875 was revised to replace the mechanical relays on it with a solid state circuit. [. . . ] The difference between the old board and revised board is easily identified by the part number imprinted on the board (which is the bare board part number). It is recommended that the old board be replaced with the revised board for all PPCH and PPCH-G pressure controller/calibrators in the field. Figure 2. Valve driver board installed Remove the (6) 2. 5 mm socket head bolts that hold the control valve cover plate. Figure 1. Valve driver board Lift off the cover plate carefully and disconnect the servo driver cable from the valve driver board. Disconnect the stepper motor and micro switch connections from the valve driver board. Remove the four 2. 5mm sockethead cap bolts that hold the valve driver board to the chassis and remove the board. [. . . ] Access the PPCH or PPCH-G mechanical module by opening the fasteners on the rear panel and sliding out the module (see Section 5. 9 of the PPCH Operation and Maintenance Manual). Document 560084 060907 DH Instruments, Inc. 4765 East Beautiful Lane Phoenix AZ 85044-5318 USA Tel 602. 431. 9100 Fax 602. 431. 9559 dhi@dhinstruments. com www. dhinstruments. com [. . . ]