Setra Systems 278 User manual

4
Model 278
Barometric Pressure Transducer
1.0 GENERAL INFORMATION
Your Setra barmetric 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. This pressure
transducer has the following excitation 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 MECHANICAL INSTALLATION
2.1 Media Compatibility
Model 278 transducers are designed to be used with air (up to 95% RH) or non-
conducting gases. Use with liquids or corrosive gases may damage the unit.
2.2 Environment
The operating temperature limits of the Model 278 are -40°C to +60°C
(-40°F to +140°F).
2.3 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
5.0 RETURNING PRODUCTS FOR REPAIR
Please contact a Setra application engineer (800-257-3872, 978-263-1400) before
returning unit for repair to review information relative to your application. Many times
only minor field adjustments may be necessary.When returning a product to Setra, the
material should be carefully packaged and shipped prepaid to:
Setra Systems, Inc.
159 Swanson Road
Boxborough, MA 01719-1304
Attn: Repair Department
To assure prompt handling,please supply the following information and include it inside
the package or returned material:
1. Name and phone number of person to contact.
2. Shipping and billing instructions.
3. Full description of the malfunction.
4. Identify any hazardous material used with product.
Notes: Please remove any pressure fittings and plumbing that you have installed and
enclose any required mating electrical connectors and wiring diagrams.Allow approxi-
mately 3 weeks after receipt at Setra for the repair and return of the unit.
Non-warranty repairs will not be made without customer approval and a purchase order
to cover repair charges.
Calibration Services
Setra maintains a complete calibration facility that is traceable to the National Institute of
Standards & Technology (NIST). If you would like to recalibrate or recertify your Setra
pressure transducers or transmitters, please call our Repair Department at 800-257-3872
(978-263-1400) for scheduling.
6.0 WARRANTY AND LIMITATION OF LIABILITY
SETRA warrants its Model 278 Transducer products to the original consumer purchaser against
defects for a period of two years from the date of sale by SETRA, as shown in its shipping documents.
Without charge,SETRA will repair or replace products found to have manufacturing defects within
the warranty period.
The serial number or date code must not have been removed,defaced or otherwise changed. SETRA
must be notified in advance of any returns;any products returned to SETRA must be transportation
prepaid.The foregoing warranty is in lieu of all warranties, express, implied or statutory, including
but not limited to,any implied warranty of merchantability for a particular purpose.
SETRA’s liability for breach of warranty is limited to repair or replacement, or if the goods cannot be
repaired or replaced, to a refund of the purchase price. SETRA’s liability for all other breaches is
limited to a refund of the purchase price. In no instance shall SETRA be liable for incidental or
consequential damages arising from a breach of warranty, or from the use or installation of its
products.No representative or person is authorized to give any warranty other than as set out above
or to assume for SETRA any other liability in connection with the sale of its products.
159 Swanson Road, Boxborough, MA 01719-1304
Tel: [phone], Fax [phone]
Email: [email protected],Web: www.setra.com
in.
mm
2.4
61
Front View
3.0
76
3.6
91
Dimensional Outline Drawing
SS2123 Rev A 03/16/04

23
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.
1EXTTRIG 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.
Terminal 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 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
VV