RPM4 pressure monitors can be used with PPC pressure controllers as an external Q-RPT. If the PPC and RPM4 are not communicating correctly (errors, messages that a mode isn't available, etc.) after calibration or repair, the settings probably need to be independently set to match. Here is a procedure to do this.
A PPC pressure controller can be a PPC3, PPC4, PPCH or PPCH-G.
1. Turn both the PPCH and RPM4 off
2. Disconnect one end of the RS232 cable between them so they are not connected
3. Turn on the RPM4
4. Change to mode (absolute, gauge, etc.) and units that you want
5. Set AutoZero state as desired. You might have to temporarily set the Special --> Preferences --Level setting to "None" to change the AutoZero on/off state
6. Change to other mode, units and/or Q-RPT module that you use and repeat step 5
7. Set Level back to prior setting
8. Set mode and units to most common that you use
9. Turn off RPM4
10. Repeat steps 4 to 9 for the PPC
11. Connect the RS232 cable between the RPM4 and the PPC
12 . Turn on the RPM4, allow it to initialize to its main screen
13. Turn on the PPCH, allow it to initialize to its main screen
14. Choose the active Q-RPT by the [RPT] or [RANGE] buttons, or preferably use the AutoRange feature to do this