The ability of the PPCH-G to successfully work as the AutoFloat controller for a PG7202 is directly related to the pressure circuit being leak free. This article addresses the specific configuration of a PPCH-G + PG7202 system with an AMH-100.
Leak Check PG7202 with PPCH-G:
Ideally, the PPCH-G leak test should not be performed in Dynamic mode as this mode uses a heating element as part of the fine pressure control process, (the mechanism is known as the Thermal Pressure Control unit). If in Dynamic control mode, change to Static or High Volume Dynamic control mode. Wait five minutes for the heater to cool down before measuring the leak rate.
To change control modes: [SETUP] button, <6control>,<2mode>
Leak Test Procedure:
- From the PG7000 Terminal, command the AMH-100 to load all the masses onto the piston:
- From the front panel of the PPCH-G, press the [SET P] key and set a target for the maximum pressure that the system will allow. Be mindful of any DUTs that may be plumbed to the system. Press [ENT] to execute the Set command.
- Cancel the active control when the pressure reaches the target (you do not need to wait for the green “Ready” light to come on) by pressing the [ESC] key.
- Wait 5 minutes for the pressure adiabatic effects to settle out.
- Run the internal leak check function:
- [LEAK CK],<1Run>, press ENTER to accept 15 seconds
- The results of the leak check: top line is the total change in pressure over 15 seconds; the bottom line is the average rate of pressure change per second.
- Pass Requirements: Rate = -0.002 %/sec of reading or less. For example: if the leak check pressure was 2500 psi, then 0.002%*2500 = 0.05 psi/sec. The smaller the leak rate, the better. (At the factory, we aim for a leak rate of 0.001% of reading.)
- Vent the pressure.