Intek 111D User Manual

Page 12

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MAN114 REV C.wpd

3.4 OUTPUT CURVE

Figure 3 (p. 20) is the final linearized output curve for your unit. The instrument has been calibrated over
the actual flow rate range indicated on the ordinate (Y axis).

3.5 TRANSDUCER & ELECTRONICS FUNCTIONAL TESTS

A test of the

Rheotherm instrument functional operation can be performed in three phases as outlined

below:

Transducer continuity check, Diagram A on the next page.

Transducer isolation check, Diagram B on the next page.

Front end board TP4 signal to 4/20 mA output using Table II, calibration data.

1.

The transducer continuity check is performed as follows:

A.

Turn off power to the unit.

B.

Disconnect the transducer cable from the electronics.

C.

Make resistance measurements between the cable pairs as shown in Diagram A. The
readings should be as indicated; if not, consult factory for repair.

2.

The transducer isolation check is performed as follows:

A.

Turn off power to the unit.

B.

Disconnect the transducer cable from the electronics.

C.

Make the circuit connections illustrated in Diagram B.

D.

Probe all the conductors and note the voltages with respect to the shield. All readings
should be less than 0.5 Vdc.

3.

The sensor input to flow output of the electrical circuit is checked as follows:

A.

Construct the dummy transducer as illustrated in Diagram C.

B.

Turn off power to the unit.

C.

Disconnect the transducer cable from the instrument.

D.

Connect the dummy transducer to the instrument input.

E.

Restore power.

F.

Connect a DC voltmeter to the TEMP (+) pin on the front end board (see Figure 2 on page
18) and to GND (-). Connect a second DC voltmeter to pin

)

T (+), and again to GND (-).

G.

Vary the R1 & R3 pots of the dummy transducer to obtain values for TEMP and

)

T of

Table II Orginal Calibration Data for Functional Test. Compare the measured non-linear
output (TP4) and the indicated linear flow rate to data of Table II. If there are large
discrepancies between these numbers, contact factory for advice.

*resistors of dummy transducer

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