PRESSURE RE-RANGING PROCEDURE
1
. With the transmitter correctly connected to the com-
panion receiver, an accurate milliameter with a full scale
reading of approximately 30 mA should be inserted in
series with the current loop. A controllable pressure
source capable of achieving the desired range should be
connected to the pressure port of the transmitter and teed
into an accurate reference pressure gauge or manometer.
The instrument must be ranged in the same position in
which it will be used. Vertical mounting is recommended.
2
. Apply electrical power to the system and allow it to
stabilize for 10 minutes.
3
. With no pressure applied to the transmitter, adjust
“zero” control so that loop current is 4 mA.
4
. Apply full range pressure and adjust loop current to 20
mA using “span” control.
5
. Relieve pressure and allow transmitter to stabilize for
two minutes.
6
. Zero and span adjustments may be interactive, so
repeat steps 3 through 5 until zero and full range pres-
sures consistently produce loop currents of 4 and 20 mA
respectively.
7
. Remove the milliameter from the current loop and pro-
ceed with final installation of the transmitter and receiver.
MULTIPLE RECEIVER INSTALLATION
An advantage of the standard 4-20 mA output signal pro-
vided by the Series 634ES Pressure Transmitter is that
any number of receivers can be connected in series in the
current loop. Thus, an A-701 Digital Readout Accessory,
an analog panel meter, a chart recorder, process control-
ling equipment, or any combination of these devices can
be operated simultaneously. It is only necessary that
these devices all be equipped with a standard 4-20 mA
input and that proper polarity of the input connections be
observed when inserting the device in the current loop. If
any of the receiving devices displays a negative or down-
scale reading, this indicates that the signal input leads are
reversed.
MAINTENANCE
Upon final installation of the Series 634ES Transmitter and
the companion receiver, including the A-701 Digital
Readout, no routine maintenance is required. A periodic
check of system calibration is recommended. The Series
634ES Pressure Transmitter is not field serviceable and
should be returned, freight prepaid, to the factory if repair
is required. The A-701 Digital Readout should be
returned to the manufacturer if service is needed. Refer
to the A-701 instruction sheet.
©Copyright 2002 Dwyer Instruments, Inc.
Printed in U.S.A. 6/02
FR# 01-440577-04, Rev. 3
Series 634ES Pressure Transmitter
Specifications - Installation and Operating Instructions
Bulletin E-69ES
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
E-69ES (634ES)-4.0 6/26/02 11:05 AM Page 4
