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Model 278
Barometric Pressure Transducer
1.0 GENERAL INFORMATION
Your Setra barometric pressure transducer has been carefully calibrated before
shipment to you, and it should be handled with the same care given any
precision instrument.
The Model 278 barometric pressure transducer senses absolute pressure and
converts this pressure to a proportional high level analog output. Your
pressure transducer has one of the following excitations and output:
Excitation Output
9.5 to 28 VDC 0 to 2.5 VDC
9.5 to 28 VDC 0 to 5 VDC
Check the label on the unit to confirm the excitation and output.
2.0 EMC Certification
This product complies with EN61326 Electrical Equipment for Measurement,
Control and Laboratory use – EMC Requirements for Minimum Requirements
and Industrial Locations. Special caution should be taken to meet Standard
EN61000-4-5: 1995 Surge Immunity if any of the following conditions apply to
the installation: The product is installed outside; all or any part of the cable is
exposed to the outside; the cable is greater than 30 meters in length. In order
to meet the Surge Immunity requirements, the following conditions must be
followed during installation:
1. Shielded cable must be used, and the shield must be tied to earth ground (not power
supply ground) on at least one end of the cable shield/drain wire. The shield must be
maintained all the way from sensor to the power supply.
2. If unshielded cable is used, an earth grounded metal conduit fitting can be used to
replace the shielded cable.
3. For a sensor with a metal body or enclosure, the body/enclosure must be grounded to
earth. If a protective metal housing is used, the metal housing should be grounded to
earth
4. If a protective plastic housing is used, the housing must be able to withstand at least
2 KV from the housing to earth ground, without damaging the circuit.
3.0 MECHANICAL INSTALLATION
3.1 Media Compatibility
Model 278 transducers are designed to be
used with air (up to 95% RH) or non-con
ducting gases. Use with liquids or corrosive
gases may damage the unit.
3.2 Environment
The operating temperature limits of the
Model 278 are -40°C to +60°C
(-40°F to +140°F).
3.3 Pressure Fittings
The Model 278 is supplied with a 1/8 inch
barbed fitting for the pressure connection
and typically installed with push-on tubing.
Installation Guide
3.6
91
2.4
61
in.
mm
Front View
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