Setra-system Model 278 Bedienungsanleitung PDF herunterladen (Seite 2)

3.0 ELECTRICAL INSTALLATION

External access to the Model 278 electrical terminations is provided on

the terminal strip at the bottom of the unit.

3.1 Voltage Output Units

The Model 278 barometric pressure transducer has five electrical

terminals available for wiring. This unit can be wired as a 4 wire (Fig. 1) or

3 wire (Fig. 2) device. Note:

Four wire connection is recommended to

avoid the voltage drop in the negative power line, which can affect

the accuracy of the pressure measurement.

1EXT TRIG External Trigger Signal

0 VDC Sleep Mode

3-28 VDC Operating Mode

2AGND* Analog Signal Ground

3GND* Supply Ground (Negative Power)

4SUPPLY Supply (Positive Power)

5VOUT Voltage Output

*Both grounds (AGND and GND) are in the same electrical potential in the

transducer.

Term inal

Function

No.

4.0. CALIBRATION

The 278 transducer is factory calibrated and should require no field adjustment.

Figure 1

Figure 2

1 2 3 4 5

Four Wire Connection

Three Wire Connection

3.2 Adjustment for Continuous Operation

The Model 278 has two operating modes: normal (operating mode) and shut-

down (sleep mode). The unit is shipped in sleep mode (shutdown). To change

to normal operation mode, an external trigger voltage is needed so that the

transducer can wake up and measures pressure. For continuous operation, the

“External Trigger”, terminal 1, can also be wired with a jumper (external wire, not

provided) to the supply, terminal 4, (see Figure 3).

1 2 3 4 5

Figure 3

1 2

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Setra-system Model 278 Bedienungsanleitung Seite 2