Meriam M4 Series Precision Calibrator Data Logger Manual - Manual (Page 39)

ZM4 Instruction Manual 9R87-B June 2012
39
Applications (continued)
Vacuum calibration can be performed by venting the high pressure
connection (P1) and applying vacuum to the lower pressure connection (P2).
Atmospheric pressure is the reference for all vacuum measure elements.
Absolute pressure calibrations use an AI sensor which has an internal
absolute zero reference. You will notice when powering up an M4 with an AI
sensor, it will read the local barometric pressure. Simply connect the vacuum
(or pressure) source to the single port of the manifold. To zero an absolute
sensor a full vacuum of 200 micron or less must be applied.