Setra 280G User Manual

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 specication 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: