Cameron Barton 752, User Manual

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Model 752 and 752A Differential Pressure Transmitters Section 1
Span Control
When a transmitter leaves the factory, it has a fixed range—0-120”w.c., 0-63
psi, etc. Typically the output from the transmitter varies from 4-20 mA or 10-
50 mA. This output is linear with the measured variable, as shown in Figure
1.2.
10
50
OR
ELECTRONIC SIGNAL mA
4
20
20 40 60 80 100
% OF FULL SCALE DP RANGE
Figure 1.2—Output calibrated to upper limit of DPU range
During calibration, the span control is used to adjust the instrument’s output
to 20 mA or 50 mA output signal at the maximum pressure setting of the
instrument.
Specifications
Input Range .................................... 0-30 inches (water column) to 0-500 psid
(Consult factory for other ranges)
Output ............................................. 4-20 mA or 10-50 mA, direct or reverse acting
Reference Accuracy* ...................... ±0.5% of factory-calibrated span, including effects of
non-linearity, hysteresis, and repeatability
(±0.25% accuracy optional)
Zero/Span Adjustments .................. Combined zero/span field adjustments are limited to
±5% of factory-calibrated span. See Zero Suppres -
sion and Custom Span for additional options.
Zero Suppression ........................... Available as an option.
0% to 50% suppression of factory-calibrated span.
Custom Span .................................. Available as an option.
20% to 100% of factory-calibrated span. Minimum
span is 30” w.c
Sensitivity* ...................................... ±0.01% of factory-calibrated span
Power Requirements
(See Figure 3.3, page 16 )
4-20 mA ....................................... 12 VDC plus 2 VDC per 100-ohms load (to 70 VDC
maximum)
10-50 mA ..................................... 12 VDC plus 5 VDC per 100-ohms load (to 70 VDC
maximum)