Omega Vehicle Security PSW490B - Manual (Page 4)

For accurate setpoint calibration, mount the
switch on a calibration stand, a pump or catalog
Omega DWT 1305 deadweight gauge tester. A
suitable reference standard such as a Test Gauge
is necessary to observe convenient changes in
pressure.
A typical calibration procedure would be
as follows:
Static Working Pressure
– 300 psi
Adjustable Differential Range
– 5-200 psid
Differential SetPoint
– 150 psi above static working pressure
Simultaneously raise the high and low side pres-
sure to 300 psi. Maintain the low side pressure at
300 psi. Raise the high side pressure to 450 psi to
obtain 150 psi differential.
Turn the adjustment nut until the switch
changes mode at 150 psi differential. When the
setpoint has been achieved, raise and lower the
high side pressure to ensure that the differential
setpoint is correct.
After installation of the control replace cover to
insure electrical safety and to protect internal
parts from the environment.
TERMINAL BLOCK
FRONT SWITCH
TERMINAL BLOCK
REAR SWITCH
NC
NO
C
NC
NO
C
Note – As indicated above, adjustment of set-
point is made by use of 7 ⁄
8
˝ nut. Precision switch
element mounting screws and bracket adjusting
screw are factory sealed and should not be
tampered with.