MKS 640A/641A, Manual, Page: 55 / 88

Applications with a Large Differential Pressure Chapter Three: Overview
42
Applications with a Large Differential Pressure
Applications with a large differential pressure between the inlet and outlet, or a large inlet
pressure, may require special precautions:
•
If the inlet pressure is more than two times the transducer full scale pressure or 45 psia,
whichever is greater
You must ensure that the valve will never be fully opened to the transducer. Pressures in
excess of 45 psia or two times the transducer full scale (whichever is greater) may
damage the transducer.
•
The inlet pressure on the valve is 150 psig (orifice sizes A through 4) or 30 psig (orifice
sizes 5 and 6)
This is the maximum inlet pressure rating of the valve. The force of high inlet pressure
on the valve may inhibit valve movement. A normally closed valve may be unable to
open.
Labels
The 640 Series controller carries a serial number label which identifies the serial number, model
number, calibration gas, full scale flow rate, and pressure range. It also displays the CE Mark
which indicates compliance with European directives. The serial number label is located on the
back of the unit.
640A12TW1V12V
Serial #:
Model #:
012345678
MKS In str u men ts, Inc.
Range: 100 TORR
Made in USA
Figure 20: Serial Number Label