Disabling A Protection Or Control Set Point; Zero And Atm Calibration Modes - MKS HPS 937A Series Owner's Operation And Maintenance Manual

Disabling a Protection or Control Set Point

1 Set the Gauge Select switch to the desired set point.
2 Hold the Down push button until the set point is at the
bottom of its range.
3 Release and depress it once more. The set point will
decrement to 0.0.
4 Press Up to return the value to the bottom of the range.
Setting a set point to 0.0 deactivates it. Protection and Control set points are
factory preset to 0.0.

Zero and ATM Calibration Modes

Calibration may be necessary if the vacuum or atmosphere reading of the
sensor has drifted or a sensor has been replaced. The calibration provided by
the Series 937A controller is designed to improve the accuracy of the sensor;
however, it does not provide a NIST traceable calibration. Also, this feature is
not intended to correct the output of the sensor for different gases.
In order to perform a calibration (except for capacitance manometer), the
UCAL Enable/Disable switch on the rear panel of the Analog Module must
be set for Enable (page 32). If it is not, U C A L D I S A B will be
displayed in the Zero or ATM Calibration mode indicating that the
calibration can not be changed.
The UCAL Enable / Disable switch does not reset a sensor to
its factory calibration. It simply allows or prevents changes to
existing sensor calibration.
Calibration can also be enabled or disabled with the optional Communications
Module. If disabled, the REMOTE indicator will appear and U C A L D I S A
B will be displayed. In this case, send the command ECAL to the
Communications Module. Enabling calibration can also be done from the
front panel by turning the Function Select switch to Leak Test , turning the
power off for 5 seconds, and turning the power back on.
If the Gauge Select switch is set to a channel that cannot be calibrated, N O
will appear on its display line, and channels with suitable sensors will be
indicated. There is no calibration provided for the cold cathode sensor and
only zero calibration is provided for the capacitance manometer.
There are two types of calibration, Factory and User.
Factory Calibration resets the calibration value for the selected
channel to the factory default for the sensor type installed. If the
sensor module type or the capacitance manometer head range is
changed on the Analog Module, the calibration will be reset to the
factory value when the controller is turned on.
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937A Multi-Sensor System