©Copyright 2017 Dwyer Instruments, Inc.
Printed in U.S.A. 3/17
FR# 443402-00 Rev. 4
ELECTRICAL CONNECTIONS
CAUTION: Do not exceed specified supply voltage ratings. Permanent damage not
covered by warranty will result. This unit is not designed for 120 or 240 volts AC line
operation.
Electrical connections are made to the terminal block located in back of the transmitter.
Terminals are and - (see Fig. B below).
Wire Length
The maximum length of wire connecting transmitter and receiver is a function of wire
size and receiver resistance. Wiring should not contribute more than 10% of the
receiver resistance to total loop resistance. For extremely long runs (over 1000 feet),
choose receivers with higher resistance to minimize size and cost of connecting leads.
Where wiring length is under 100 feet, hook-up wire as small as 22 AWG can be used.
2-Wire Operation
An external power supply delivering 10-35 VDC with minimum current capability of
40 mA DC (per transmitter) must be used to power the control loop. See Fig. C for
connection of the power supply, transmitter and receiver. The range of appropriate
receiver load resistance (RL) for the DC power supply voltage available is expressed
by the formula and graph in Fig. D. Shielded two wire cable is recommended for
control loop wiring. If grounding is required, use the negative side of the control loop
after the receiver.
USER CALIBRATION
The transmitter may be user calibrated with two buttons on the front. The standard
models have buttons labeled “ZERO” and “SPAN”. LCD models have buttons labeled
“ZERO” and “UNITS”. The “UNITS” button on the LCD models has 2 functions. If
pushed for less than 2 seconds and released the pressure units that are displayed on
the LCD will change when the button is released. If pushed and held for 4 - 5 seconds
the “UNITS” button serves the same function as the “SPAN” button on the standard
models.
To calibrate the transmitter you will need three pieces of equipment. You will need
a calibrated pressure source capable of generating a stable pressure value for
the maximum range of the unit under test, an instrument capable of validating the
calibration pressure, and an ampmeter, capable of measuring mA, to measure the
current output from the unit under test. The transmitter is calibrated using the following
procedure.
Preparation
– Connect the ampmeter and power supply, being careful to observe
polarities. The transmitter must be calibrated in a vertical position.
Performing ZERO Calibration, SPAN Calibration or Restore Factory
Calibration Coefficients:
1. Press both the ZERO and UNITS/SPAN buttons simultaneously for 6 or more
seconds. Release both buttons. The units indicator on the LCD should blink on
and off. This indicates the gage is ready for calibration or restoration of
coefficients. The units indicator blinks for approximately 10 minutes, then stops
blinking.
2. a) ZERO calibrate the gage by applying no pressure to the gage and
then pressing the ZERO button for 3 seconds.
b) SPAN calibrate the gage by applying full-scale pressure to the gage and
then pressing the UNITS/SPAN button for 3 seconds.
c.) Restore the gage’s factory calibration coefficient by pressing both the ZERO
and UNITS/SPAN buttons simultaneously for 3 seconds.
MAINTENANCE
Upon final installation of the Series DM2000 Differential Pressure Transmitter and
the companion receiver no routine maintenance is required. The Series DM2000
Transmitter is not field serviceable and should be returned, freight prepaid, to the
factory if repair is required. Please enclose a description of the problems encountered
plus any available application information.
Figure
B
Figure
C
Figure D
2-Wire Connections
Power Supply Voltage – VDC (2-wire)
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
50
To
tal Receiver Resistance ()
Maximum Value (1250 )
R Max. =
0 5 10 13 15 20 25 30 35 40
L
Vps–10.0
20mA DC
Operating
Region
RECEIVER
SERIES
DM-2000
PRESSURE
TRANSMITTER
1
2
POWER
SUPPLY
10-35 VDC
mA
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
Phone: 219/879-8000
Fax: 219/872-9057
dwyer-inst.com
e-mail: [email protected]
