8270A/8370A
Operators Manual
34
Pressure Measurement
A visual measurement indicator on the UI (also known as the “Ready indicator”)
indicates when pressure control settings are satisfied and pressure can be
measured. See Table 13 for a list of measurement indicators and their
definitions. See
Pressure Control Settings
for detailed control settings information
for different control modes.
Table 13. Measurement Indicator
Indicator
Definition
Not Ready
Indicates control settings are not satisfied. The Product cannot make a
measurement at this time.
Ready
Indicates control settings are satisfied. The Product can make a measurement
at this time.
Vented
This is shown when the Product is vented to indicate that the Product can now
make an ATM or 0 psig measurement.
Venting…
This is shown when the Product is in the process of venting all of the test
pressure.
Pressure Control Settings
This section explains the pressure control settings of the Product. Some of these
settings can be accessed on the main screen but all are located in the Control
Settings in the Setup Menu.
Control Modes
The Product offers different control modes to control pressure:
Dynamic A
mode sets the target pressure and constantly adjusts to maintain
the target. The control is tuned to reach the setpoint quickly, which can result
in momentary overshoot.
Dynamic B
mode sets the target pressure and constantly adjusts to maintain
the target. The control is tuned to minimize the amount of overshoot when
reaching the target.
Static
mode sets the target pressure and stops controlling, adjusting only
when the measured pressure has exceeded specific limits.
The subsequent sections give more information on each mode. When controlling
to a setpoint, the Product appears to stop at approximately 10 % away from the
setpoint. It will quickly fine tune the valve settings before it gets to the setpoint.
This may appear as a leak in the system but is normal system operation.