Dwyer instruments, inc – Dwyer 677B User Manual

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Electrical
The Series 677B is a two (2) wire circuit (+SUPPLY, -RECEIVER) with a 4 to 20 mA
output. The unit is calibrated at the factory using a 250 ohm load at 24 VDC.

WIRING DIAGRAM FOR 677B SERIES

Calibration
The 677B series is factory calibrated and should require no field adjustment.
However, the zero adjustment is provided near the screw terminal strip. Whenever
possible, any zero and/or span offsets should be corrected by software adjustment in
the user’s control system. Use the zero and span adjustments on the 677B series only
if absolutely necessary. The 677B series is calibrated in the vertical position at the
factory (baseplate vertical). For use in any other orientation, position the unit and
follow the adjustment procedure listed below. If a change in range is needed, contact
the Customer Service Department for a replacement in the appropriate range.

Zero Adjustment
While monitoring the current output with both pressure ports open to atmosphere, the
zero may be adjusted. For unidirectional pressure changes, turn the zero adjustment
screw until a reading of 4 mA (± .16 mA) is achieved. For bidirectional ranges, set the
zero to 12 mA (± .16 mA).

MAINTENANCE
Upon final installation of the Series 677B Transmitter, no routine maintenance is
required. The Series 677B is not field serviceable and should be returned if repair is
needed (field repair should not be attempted and may void warranty). Be sure to
include a brief description of the problem plus any relevant application notes. Contact
customer service to receive a return goods authorization number before shipping.

DWYER INSTRUMENTS, INC.

Phone: 219/879-8000

www.dwyer-inst.com

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.

Fax: 219/872-9057

e-mail: [email protected]

Printed in U.S.A. 5/14

FR# R8-443887-00 Rev. 3

POWER

SUPPLY

16-32 VDC

PRESSURE

TRANSMITTER

RECEIVER