SOR 534HS Two-Wire Pressure Transmitters - Manual (Page 5)

Form 953 (03.13) ©SOR Inc. 5/12
Calibration
Two calibration screws (zero and span) are located underneath the adjustment cover. (See
) Loosen the cover screws slightly (do not remove) and rotate the cover to reveal the
adjustment screws.
Numbers on the enclosure identify the adjustment screws: 1, 2 and 3.
Adjustment #1: Zero
Adjustment #2: Not used
Adjustment #3: Span
Unless specified otherwise, the transmitter is factory calibrated to 1 VDC @ 0 psi and 5
VDC at the upper limit of the adjustable range specified on the nameplate.
Calibration Procedure
The zero and span calibration procedure should be performed under ambient process
temperature conditions.
A pressure source with a calibrated reference gage, a voltmeter and a DC voltage supply
are required. Note the adjustable range on the instrument nameplate. For both zero and
span adjustments, turn the adjustment screw clockwise to increase, counterclockwise to
decrease.

Connect the transmitter as shown in Figure . Case ground must be connected to
earth ground to ensure EMI/RFI protection.

Apply pressure at which 1 VDC output is desired. (Zero may be adjusted up to +10% of
the upper range limit.)

When zero is elevated above 0 psi, maintain 80% of the transmitter range between the 1
VDC and 5 VDC points.

With pressure source steady at the desired zero level, rotate the zero adjustment (#1)
for a 1 VDC indication on the voltmeter.

Apply pressure at which 5 VDC output is desired. Span may be adjusted from 20 to
100% of the upper range limit. (Maximum turndown is 5:1.)

With pressure source steady at the desired span level, rotate the span adjustment (#3)
for a 5 VDC indication on the voltmeter.

Repeat Steps 2 through 6 as needed if offsetting 1 VDC from the normal zero point.
If interaction occurs, turn zero and span 15 turns counterclockwise. Repeat Steps 2
through 7 above.