OUTPUT RANGING
Each Series 604D Indicating Transmitter is factory calibrat-
ed to produce 4 mA at zero scale reading and 20 mA at full
scale reading. The following procedure should be used to
check the accuracy of the transmitter output.
1. With unit connected to its companion receiver, insert an
accurate milliammeter with a full scale reading of approxi-
mately 30 mA in series with the current loop.
2. Connect a controllable source of pressure to one leg of a
tee, one leg to the high pressure port of the unit being test-
ed and the third leg to a test gage or manometer with 2% or
better accuracy. Be sure the low pressure port is vented to
atmosphere. This calibration check must be done in the
same position in which the unit will be operated. Vertical is
recommended.
3. Apply electrical power to the system and allow 10 min-
utes warm-up time for components to stabilize.
4. With no pressure applied to the system adjust ZERO con-
trol inside electrical enclosure to produce exactly 4 mA cur-
rent.
5. Apply full scale pressure as observed on the test gage or
manometer and adjust SPAN control for exactly 20 mA cur-
rent.
6. ZERO and SPAN controls are slightly interactive so steps
4 and 5 should be repeated until outputs are consistently 4
and 20 mA, respectively.
7. Remove the milliammeter and test gage from the setup,
make connections to system pressure source(s) and place
unit in service.
MULTIPLE RECEIVER INSTALLATION
An advantage of the standard 4-20 mA DC output signal
used in Series 604D Transmitters is the compatibility with a
wide range of receivers. Devices such as the A-701 Digital
Readout, A-702 Digital Readout with alarms, an analog
panel meter, a chart recorder and other process control
equipment can be operated simultaneously. It is only nec-
essary that all devices be designed for a standard 4-20 mA
input, the proper polarity of input connections be observed
and the combined receiver resistances must not exceed the
maximum for the current loop. If any receiver indicates a
negative or downscale reading, the signal input leads are
reversed.
MAINTENANCE
After final installation of the Series 604D Indicating Pressure
Transmitter, no routine maintenance is required. A periodic
check of output calibration is recommended following the
procedure described under OUTPUT RANGING.
Otherwise, the transmitters are not field repairable and
should be returned, freight prepaid, to the address below if
service is needed. Be sure to include a clear description of
the problem plus any application information available.
Dwyer Instruments, Inc.
Attn: Repair Dept.
102 Highway 212
Michigan City, IN 46360
©Copyright 2001 Dwyer Instruments, Inc.
Printed in U.S.A. 1/01
FR# 01-440830-00 Rev.1
Series 604D Indicating Pressure Transmitter
Specifications - Installation and Operating Instructions
Bulletin E-34
Page 4
DWYER INSTRUMENTS, INC.
Phone: 219/879-8000
www.dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46361, U.S.A.
Fax: 219/872-9057
e-mail: [email protected]
Lit-By Fax: 888/891-4963
