Setra 265 Installation Guide

Installation Guide

Setra Systems Model 265

Differential Pressure Transducer

1.0 GENERAL INFORMATION Every Model 265 has been tested and calibrated before shipment. Speciﬁc

performance speciﬁcations are shown on page 3 of this Guide.

Setra Systems 265 pressure transducers sense differential or gage (static) pres-

sure and convert this pressure difference to a proportional high level analog output for both unidirectional and bidirectional pressure ranges. The Model 265 is available in the following excitation and output versions:

Excitation Output 9-30 VDC 0-5 VDC

9-30 VAC 0-5 VDC 12-30 VAC 0-10 VDC 9-30 VDC (measured between the + and - terminals) 4-20 mA

Check the label on the unit to conﬁrm the excitation and ouput.

2.0 MECHANICAL INSTALLATION

2.1 Media Compatibility

Model 265 transducers are designed to be used with air or nonconducting gases. Use with liquids or corrosive gases will damage the unit.

2.2 Environment

The operating and compensated temperature limits of the 265 are 0°F to +150°F (-18°C to +65°C).

2.3 Pressure Fittings The Model 265 is supplied with two factory installed 1/4” O.D. pressure

ﬁttings for the pressure signal connection and typically installed with 1/4” push-on tubing. Both the positive (high) pressure port and the reference (low) pressure port are located on the front of the unit, labeled “HIGH” and “LOW” respectively. For best results (shortest response times), 3/16” I.D. tubing is suggested for tubing lengths up to 100 feet long, 1/4” I.D. for tubing lengths up to 300 feet, and 3/8” I.D. for tubing lengths up to 900 feet.

3.0 ELECTRICAL INSTALLATION

If the Model 265 is supplied with the optional Conduit Enclosure, access the

electrical terminations by removing the cover.

For CE compliance a shielded cable with both ends properly grounded is

required.

3.1 Voltage Output Units The Model 265 voltage output is a 3-wire circuit, with three terminals avail-

able for wiring. These terminals have the designation COM, OUT and EXC (see

Diagram 1). [Note: The - designation above COM and the + designation above

EXC are designations for the current output terminals.] The -Excitation and

-Output are commoned on the circuit (see Diagram 2). The 265 voltage output

can operate from 9-30 VDC or 9-30 VAC excitation with 0-5 VDC output, or 12-

30 VAC excitation with 0-10 VDC output.

Diagram 1

Voltage Circuit Diagram

- COM

Readout

DAS

OUT

Model

265

SPAN ADJUSTMENT

ZERO ADJUSTMENT

Power

Supply

+ EXC

Diagram 2

+EXC Connected to positive terminal of DC/AC power supply

-COM Connect as the reference for power supply and output signal OUT Connect to positive terminal of control or pressure

3.2 Current Output Units

The Model 265 is a two-wire loop-powered 4 to 20mA current output unit (see Diagram 3). The current ﬂows into + terminal and returns back to the power supply through the - terminal (see Diagram 3). The power supply must be a DC voltage source with a voltage range between 9 and 30 measured between terminal + and - terminals. The unit is calibrated at the factory with a 24 VDC loop supply voltage and a 250 ohm load.

CurrentCircuit Diagram

9 to 30 VDC+_

Current

Monitoring

Device

265

4.0. CALIBRATION

The 265 transducer is factory calibrated and should require no ﬁeld adjust ment. Generally, the mounting position will have a zero shift effect on ranges below 1” WC. Whenever possible, any zero and/or span offsets should be corrected by software adjustment in the user’s control system. However, both zero and span adjustments are accessible either on the front of the unit or by removing the optional conduit enclosure. The 265 transducer is calibrated in the vertical position at the factory.

4.1 Voltage Output Zero Adjustment

While monitoring the voltage between the positive output (OUT) and common (COM), and with both pressure ports open to atmosphere, the zero may be adjusted by turning the zero adjustment screw. (See Diagram 1 for

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