Dwyer 648C - Manual (Page 2)

Electrical
The Series 648B and 648C are two (2) wire circuits (+SUPPLY, -RECEIVER) with 4
to 20 mA outputs. The units are calibrated at the factory using a 250 Ω load at 24
VDC.
WIRING DIAGRAM FOR 648B SERIES
Calibration
The 648B and 648C series are factory calibrated and should require no field
adjustment. However, both zero and span adjustments are 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 only if absolutely necessary. The 648B and 648C transmitters are
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. Use push-button adjustment on the front of the unit to reset
zero.
Span Adjustment
Span or output adjustments should only be done using an accurate pressure standard
(electric manometer, digital pressure gage, etc.). With FS pressure applied to the high
pressure port (reference open to atmosphere), adjust span to achieve 20 mA output.
MAINTENANCE/REPAIR
Upon final installation of the Series 648B and 648C, no routine maintenance is
required. The Series 648B and 648C are not field serviceable and should be returned
if repair is needed. Field repair should not be attempted and may void warranty.
WARRANTY/RETURN
Refer to “Terms and Conditions of Sales” in our catalog and on our website. Contact
customer service to receive a Return Goods Authorization number before shipping the
product back for repair. Be sure to include a brief description of the problem plus any
additional application notes.
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]
©Copyright 2012 Dwyer Instruments, Inc. Printed in U.S.A. 6/12 FR# R1-443886-00 Rev. 2
POWER
SUPPLY
13-32 VDC
PRESSURE
TRANSMITTER
RECEIVER