Dwyer 616C User Manual
Page 3
4-Wire Connections
Figure E
Power Supply Voltage – VDC (2, 3 or 4-wire)
Figure F
Power Supply Voltage – VAC (4-Wire)
Figure G
Calibration Check
Each Series 616 Transmitter is factory calibrated to the range given in
the model chart. To check calibration and adjust if necessary, the
following procedure should be used. For purposes of clarification in these
instructions, range is defined as that pressure which, applied to the
transmitter, produces 20 milliamps of current in the loop. Zero pressure
is always assumed to be 4 milliamps.
1. With the transmitter connected to the companion receiver, insert an
accurate milliameter in series with the current loop. Full scale range
should be approximately 30 mA.
2. Connect a controllable pressure source to one leg of a tee with the
other two legs connected to the high pressure port of the transmitter and
the third leg to an accurate test gage or manometer, in an appropriate
range. The low pressure port should be vented to atmosphere.
Calibration must be performed with the unit in the same position in which
it will be mounted.
3. Apply electrical power to the unit and allow it to stabilize for 10
minutes.
4. With no pressure applied to the transmitter, adjust ZERO control so
that loop current is 4 mA.
5. Apply full range pressure and adjust loop current to 20 mA using SPAN
control.
6. Relieve pressure and allow transmitter to stabilize for 2 minutes.
7. Zero and span controls are slightly interactive, so repeat steps 4
through 6 until zero and full range pressures consistently produce
currents of 4 and 20 mA respectively.
8. Remove the milliameter from the current loop and proceed with final
installation of the transmitter and receiver.
Voltage Input
Series 616 Transmitters can be easily adapted for receivers requiring 1-
5 or 2-10 VDC inputs. Insert a 249 ohm, 1/2 watt (1-5 VDC) or 499 ohm
(2-10 VDC) resistor in series with the current loop but in parallel with the
receiver input. Locate this resistor as close as possible to the input.
Because resistor accuracy directly influences output signal accuracy, we
recommend use of a precision ±0.1% tolerance resistor to minimize this
effect. See Fig. H and J below.
3-Wire Connection (1-5 or 2-10 VDC Output)
Figure H
1300
1200
1100
1000
900
800
700
600
Total Receiver Resistance (W)
Maximum Value (1200 W)
R Max. = 65 (Vps)-490
L
Operating
Region
0 5 10 15 16 18 20 25 26 30
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
50
Total Receive
r Re
si
sta
n
ce (W)
Maximum Value (1250 W)
R Max. =
0 5 10 13 15 20 25 30 35 40
L
Vps–10.0
20mA DC
Operating
Region
PRESSURE
TRANSMITTER
POWER
SUPPLY
10-35 VDC
VDC
PRESSURE
TRANSMITTER
Receiver
mA
POWER
SUPPLY
10-35 VDC
16-26 VAC
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