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Setra Blog

by Tom Lish

For high line pressure, high differential pressure applications

The pressure difference across an orifice plate, filter, pump, valve, etc. can be sensed with two pressure transducers such as the Model 206. One transducer measures the high side pressure (P1) while the other measure the low side pressure (P2). Pressure media can be any liquid or gas compatible with 17-4 pH stainless steel.

2. Can take full line pressure either side (for P)
3. No organic seals or gaskets, etc.
4. Can reduce pressure piping by placing each transducer near its pressure source.

Option A:
Provides a two wire differential analog output proportional to differential pressure.
Applicable ratios of line pressure to differential pressure, analog output and accuracy are:

 Pressure Ratio Analog Output Accuracy 1:1 0 - 5.00 VDC ± .16% Full Scale 2:1 0 - 2.50 VDC ± .32% Full Scale 3:1 0 - 1.67 VDC ± .48% Full Scale 4:1 0 - 1.25 VDC ± .64% Full Scale 5:1 0 - 1.00 VDC ± .80% Full Scale

Pressure Ratio = Line Pressure/Differential Pressure

Both Model 206 transducers must have identical full scale pressure ranges equal to or greater than the maximum line pressure.

Example: Line pressure = 100 psig

Differential pressure = 50 psid

Pressure ratio = 100/50 = 2:1
Specify two Model 206, 0-100 psig transducers.

The signal proportional to differential pressure is read between (+) signal #1 and (+) signal #2.

Option B:
Provides a two wire ground referenced 0 to 5 VDC analog output for both the high side pressure (P1) and the low side pressure (P2). It is possible to monitor P1, P2, and P (P1 - P2) on a readout such as a digital panel meter, datalogger, scanner or recorder. The P (P1 - P2) subtraction can be performed in systems software or by using an external subtraction circuit.