MKS Granville-Phillips Mini-Convectron 275 series - Calibration

3 Installation
22
Series 275 Mini-Convectron Module with DeviceNet
Instruction Manual - 275563
3.5 Configure the Setpoint Relays for the Application
To configure setpoint relays for the module, see Section 5.2, Process Control Relays in the DeviceNet
Chapter.
If the module will measure the pressure of a gas other than N
2
or air, you must adjust relay setpoints
for the process gas. The true pressure of a gas other than N
2
or air may be substantially different from
the pressure that the output indicates. For example, outputs might indicate a pressure of 10 Torr
(1.33 kPa, 13.3 mbar) for argon, although the true pressure of the argon is 250 Torr (33.3 kPa, 333.3
mbar). Such a substantial difference between indicated pressure and true pressure can cause over
pressurization resulting in an explosion.
3.6 Calibration
Calibration improves the accuracy and repeatability of the Convectron gauge. To calibrate the
Convectron gauge, see Section 4.8 in the Operation Chapter.
3.6.1 Atmospheric Pressure Calibration
An atmospheric calibration is performed on the Convectron gauge, using N
2
, at the factory before
the module is shipped. The factory calibration sets the atmospheric calibration point to 760 Torr
(101.3 kPa, 1013 mbar) of N
2
.
Because performance varies depending on the process gas, you may wish to reset the atmospheric
calibration point if a gas other than N
2
or air is being used. Periodic resets of the atmospheric
calibration point also improve the accuracy and repeatability of the Convectron gauge near
atmospheric pressure, even if the process gas is N
2
or air.
3.6.2 Vacuum Chamber Pressure Calibration
Periodic resets of the vacuum pressure calibration point improve the accuracy and repeatability of
the Convectron gauge.
Failure to use accurate pressure conversion data for N
2
or air to other gases
can cause an explosion due to over pressurization.
If the module will measure any gas other than N
2
or air, before connecting
relays to system control devices, adjust setpoints for the process gas that
will be used.