Meriam MFT 4010 Modular Calibrator_HART Communicator - Manual (Page 21)

16
Vacuum and Absolute Pressure Calibration
Vacuum calibrations can be performed with an xDN sensor module by venting the high pressure connection to
atmosphere and applying the vacuum to the low pressure connection. Atmospheric pressure is the reference pressure
for all vacuum measurements.
Absolute pressure calibrations use a xAI sensor module. These sensor modules have an internal absolute zero
reference. Simply connect the pressure (or vacuum) source to the single port on the module.
The following diagram shows the connection for both a vacuum and an absolute pressure measurement. If the
process maintains a stable pressure, it can be used as the pressure source in some calibrations. Process
compatibility and pressure ranges of the sensor modules need to be considered for each application.