Dwyer 647 - Manual (Page 2)

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 2014 Dwyer Instruments, Inc. Printed in U.S.A. 2/14 FR# 443017-00 Rev.1
ELECTRICAL CONNECTIONS
Make all wiring connections with the power off. All circuits must be wired
to the National Electrical Code, Class 1, and in conformance with all
applicable codes and requirements with approved wiring practices. See
Figure 1 below for appropriate wiring connections
OPERATION
After applying power, allow approximately 20 to 30 minutes for
stabilization of signal.
When operating at low differential pressures of less than 5˝ w.c. or in
applications where the pressure is fluctuating rapidly – it is advisable to
insert “snubbers” for air flow restrictors in the input lines. This serves to
“steady” the output signal and keeps the signal from bouncing erratically.
ADJUSTMENTS
The Series 647 transmitters are adjusted for the specified range at the
factory and should not require further adjustments. If necessary or
desireable, the zero and span may be adjusted, however, the requested
full scale range as shipped is established with fixed resistors minimizing
the range of adjustment. The average full scale adjustment is ±10% fo
the range shipped.
“Z” – Zero Control is adjusted for 4 mA output signal at 0 psi or minimum
pressure.
“S” – Span Control is adjusted to change the full scale range of the
transmitter.
Due to resistor values required to compensate for the null off-set of the
sensing module, evidence of Zero and Span interaction may be
experienced in readjusting.
Do not adjust the bridge balance and temperature compensation
controls.
Fluid hammer and surges can destroy any pressure transducer
and must always be avoided. A pressure snubber should be
installed to eliminate the damaging hammer effects.
WARNING
Fluid hammer occurs when a liquid flow is suddenly stopped, as with
quick closing solenoid valves. Surges occur when flow is suddenly
begun, as when a pump is turned on at full power or a valve is opened
quickly.
MAINTENANCE
After final installation of the Series 647 Wet/Wet Differential Pressure
Transmitter, no routine maintenance is required. Periodic checks of
connections is recommended. Please contact Dwyer Instruments, Inc.
before returning unit for repair to review information relative to your
application. When returning a product tot he factory, carefully package
and ship freight prepaid. Be sure to include a complete description of the
application and problem and identify any hazardous material used with
the product.
ZERO SPAN
H L
1 2 3
1
2
3
1
2
3
24 VDC Power
4-20mA, 2-wire Loop Signal
+ 24 VDC In
4-20 mA Signal Out
No Connection
+ 24 VDC In
4-20 mA, 2-wire, Field Conversion
to 1-5 VDC Signal
1-5 VDC
Common
250 Ohms
Wiring Connections
Figure 1