Operating Instructions
Model 280G Pressure Transducer and Pressure Transmitter
Three-Wire, Voltage Output—Two Wire, Current Output
General Information
Your Setra transducer has been carefully calibrated before shipment to you and, it should be handled
with the same care given any precision instrument. Pressure ranges and dimensions are reported on
the specication bulletin for the transducer.
Installation
Do not use in ambient conditions corrosive to stainless steel, submerge in liquids, subject to spray
or drip, or in a high vibration environment. The 280G Series is slightly sensitive to acceleration in
the pressure tting axis, less than 0.05 psi/g typical. Factory calibrated in the vertical position, with
pressure port downward, this position often minimizes potential damage from dripping of pressure
system piping.
Installation of pressure tting:
For very high pressure we suggest using a sealant such as Loctite hydraulic sealant. For other pressure
ranges, standard sealants such as Teflon pipe tape generally are satisfactory. For the most sensitive
pressure ranges, excessive torquing of a metal pressure tting may cause slight zero shift which may
be trimmed out using zero adjustment. Use of plastic ttings often shows no noticeable zero shift.
The torquing effect does not appreciably affect linearity or sensitivity. Use the wrench flats on the
280G when attaching to ttings.
Atmospheric Reference (Gauge pressure units only)
Lower range units are subject to excessive thermal zero shift unless vented to atmosphere. The 280G
Series gauge pressure transducers and transmitters are vented to atmosphere at the terminal strip.
Electrical Connections
280G (.08 - 5.08 VDC output)
For 24 VDC Excitation (Nominal)
Care must be taken when installing this transducer that the excitation voltage is not applied to the
output lead by mistake. Excitation power, or voltage in excess of 30 VDC, inadvertently applied to
the output lead may damage the electrical circuit. Shielding or other precautions should also be
provided to assure that transient voltages in excess of 30 VDC are not applied to the output lead.
+ IN Connect to 12-30 VDC Power Supply.
+ OUT Connect to Control of Pressure Monitor.
COM. Connect as Common Return Lead for + IN
and + OUT.
CAUTION:
Wiring
Current Output (4-20 mA)
The circuit is designed to operate as a true two-wire 4 to 20 milliampere pressure transmitter
and will deliver rated current into any external load between zero and 800 ohms.
CAUTION:
The 280G Series is designed to have current flow in one direction only — please observe polarity.
We suggest that the electrical cable shield be connected to the system's loop circuit ground, thereby
improving electrical noise rejection.
Excitation
• Minimum supply voltage (VDC) = 9 + 0.02 x (resistance of receiver plus line).
• Maximum supply voltage (VDC) = 30 + 0.004 x (resistance of receiver plus line).
• Calibrated at factory using a 250 ohm load at 24 VDC.
• Variations in the power supply voltage cause less than 0.02 mA change in the transmitter’s
current output, per volt change in the power supply.
Calibration
Every model 280G is factory calibrated and should require no eld adjustment. Whenever possible,
any zero and/or span offsets should be corrected by software adjustments in the user’s control sys-
tem. However, both zero and span adjustments are accessible by removing the pan head screws and
turning the zero and span potentiometer screws inside. Pan Head screws should be replaced after
adjustment to maintain enclosure rating. Voltage output units are factory calibrated into a 50 K load.
Voltage units are operable into a 5000 load or greater. The zero factory setting is ±50 mV. Current
outputs units (4-20 mA) are factory calibrated with a 24 VDC loop to supply voltage and a 250 load.
The zero factory setting is a ±0.08 mA. The span (full scale) factory settings is ±0.16 mA. Zero and
span adjustment are approximately ±1.0 mA.
Returning products for repair
Please contact Setra (1-800-257-3872, 978-263-1400) before returning unit for repair to review information relative to your application. Many times, only minor eld 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
Attn: Repair Department
To assure prompt handling, please supply the following information and include it inside the package
of returned material:
Please remove any pressure ttings and plumbing that you have installed and enclose any required
mating electrical connectors and wiring diagrams.
Allow approximately 3 weeks after receipt at Setra for the repair and return of the unit. Non-warranty
repairs will not be made without 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 1-800-257-3872 (978-263-1400) for scheduling,
cost and turnaround estimates.
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:
Limited warranty & limitation of repair
SETRA warrants its products to be free from defects in materials and workmanship, subject to the
following terms and conditions: Without charge, SETRA will repair or replace products found to be
defective in materials or workmanship within the warranty period; provided that:
a) the product has not been subjected to abuse, neglect, accident, incorrect wiring not our
own, improper installation or servicing , or use in violation of instructions furnished by SETRA;
b) the product has not been repaired or altered by anyone except SETRA or its authorized
service agencies;
c) the serial number or date code has not been removed, defaced, or otherwise changed; and
d) examination discloses, in the judgment of SETRA, the defect in materials or workmanship
developed under normal installation, use and service;
e) SETRA is notied in advance of and the product is returned to SETRA transportation
prepaid.
Unless otherwise specied in a manual or warranty card, or agreed to in a writing signed by a SETRA
ofcer, SETRA pressure and acceleration products shall be warranted for one year from date of sale.
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.
Setra Systems, Inc.
159 Swanson Road, Boxborough, MA 01719
800.257.3872 • www.setra.com
SS-280G Rev. A 07/2017
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