Pressure Controller/Calibrator
Troubleshooting
115
Control
The Control diagnostics menu shows information about the PCM:
• Port Pressure – This menu shows the pressure measurement at the test,
supply, and exhaust ports.
• Control Module – This menu shows the PCM model number, serial number,
and firmware version.
• Control Coefficients – This menu shows the control coefficients (C0) the
PCM uses. To change the coefficients, tune the PCM with the autotune
function located in this menu.
• Autotune
– Autotune is a fully-automated procedure that runs the Product
through a series of pressures across its ranges. The Product then alters the
control coefficients to provide the best control performance. Only use
autotune when the control performance is unacceptable. The system must be
leak free, have minimal external volume, and the sealing plug on the test port
must be rated for the maximum pressure of the system.
1. Plug the test port and make sure connections are capable of accepting
pressures of 90 % FS of the highest module installed in chassis.
2. Select SETUP>Tasks>Leak Test, refer to Leak Test.
Note
With the test port plugged and no external volume, System Leak is
expected to achieve better than 0.04 %FS/Min rate.
3. Select SETUP>Diagnostic>Control>Primary>Autotune.
This process should take 20 minutes to 40 minutes. If there are leaks or the
volume is too large to run autotune, then system will error or timeout.
Leak Test
To perform a basic leak test, select the pressure range then select
SETUP>Tasks>LeakTest. Complete the following entries:
a. Setpoint – Pressure set point at which to perform the leak test
b. Stability – After achieving the setpoint, the time in seconds to wait for stability
before the Duration of the test begins.
c. Duration – The time in seconds to collect data for the leak-rate calculation
d. Mode – Defaults to external, not selectable
e. Run – Starts the test
f. Exit – Exits the leak test
Note
With the test port plugged and minimal external volume, system leak
is expected to achieve less than 0.04 % FS/minute change. To
resolve this performance, stability time must be set to allow thermal
changes to stabilize. This time is typically greater than 60 seconds
and up to 240 seconds, depending on testing conditions.
To assist with evaluation of internal leak and valve performance, use the
Pneumatic Self-Test function located on the Measure Diagnostic screen.
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