Dwyer HFT User Manual
BULLETIN F-HFT
4.500
7.125
2.0
1.5
1.0
0.5
0
Pressure Differential PSID
HFT-1123
HFT-1112
Flow Rate: SCFM @ 100 PSIG
0 5 10 15 20 25
Flow Rate: GPM
Pressure Differential PSID
HFT-23 20
HFT-23 15
HFT-24 40
HFT-25 50
12
10
8
6
4
2
0
0 10 20 30 40 50
Series HFT Flow Transmitters
Specifications – Operating Instructions
Series HFT Flow Transmitters are typically used to
transmit a signal proportional to flow rate to a process
control computer, a PLC, a recorder, or a panel-mount
display. The Flow Transmitters are used as the primary
input device to record flow rates through hydraulic and
pneumatic systems. The universal output transmitter
circuit employed by the Series HFT Flow Transmitter is
capable of producing output signals of 4-20mA, 0-5
VDC, and 0-2000 Hz square wave pulse. A 1-5 VDC
signal may be obtained from the 4-20 mA signal by
placing a 249 Ω resistor in parallel with the receiver.
SPECIFICATIONS
Service: Compatible gases or liquids.
Wetted Materials: Body: Aluminum, brass or 304 SS;
Seals: Buna-N or Fluoroelastomer; Magnet: PTFE
coated Alnico; Other internal parts: 304 SS.
Viscosity Limit: 500 SSU.
Accuracy: ±4% FS over entire range; ±2.5% over
center third of the measuring range.
Repeatability: ±1% of full scale.
Response Time: <100 msec.
Output Signal: 4-20 mA; 0-5 V; 1-5 V.
Temperature Limits: 170°F (76°C).
Note: Refer to Series HF In-Line Flow Monitor, Bulletin
F-55, “Installation and Operating Instructions” for
installation, operation, and cleaning instructions for the
basic flow monitor cartridge (included). The following
instructions are specifically for the Series HFT circuitry
for transmitting a proportional output signal.
Pressure Limits: See Chart.
Power Requirements: 12-35 VDC.
Enclosure Rating: NEMA 4X (IP65).
Shipping Weight: 1/4 to 1/2˝ female NPT Models: 3
lb (1.4 kg); 3/4 to 1˝ female NPT Models: 4.5 lb (2.0
kg); 1-1/2˝ female NPT Models: 12 lb (5.4 kg).
PRESSURE DIFFERENTIAL VS. FLOW RATE
1/4˝ FEMALE NPT
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: 219/872-9057 e-mail: info@dwyer-inst.com
1/2˝ FEMALE NPT
Phone: 219/879-8000 www.dwyer-inst.com
3/4˝, 1˝ & 1-1/2˝ FEMALE NPT
Selecting the Output
NO CONNECTION
G
2
3
1
PIN #1
+12-35 VDC
PIN #2
4-20 mA OUT
ELECTRICAL CONNECTIONS - 4-20 mA
Illustration 2
NO CONNECTION
PROGRAMMABLE JUMPER
IN POSITION CLOSEST
TO METER OUTLET
JUMPER POSITION - 4-20 mA
Illustration 3
The user may choose between reading a 0-2000 Hz
square wave pulse, a 0-5 VDC analog signal, or a two-
ire 4-20 mA analog signal by connecting to the
w
ppropriate pins on the 4-pin DIN connector and by
a
lacing the programmable jumper in the appropriate
p
position for the desired output. An analog 1-5 VDC
output may also be obtained by configuring the unit for
the two-wire 4-20 mA output and then placing a 249 Ω
resistor in parallel with the receiver. The exact output
ins and jumper positions that correspond to each
p
utput are discussed later in this manual.
o
Wiring
4-20 mA output connections:
Input Voltage: The supply voltage must be between 12
and 35 VDC. The maximum resistance that may be
placed within the current loop is given by the following
formula:
R
max
= 50(Vs- 12)
Where:
R
max
= the maximum resistance that
may be placed in the current loop (Ω).
V
s
= the value of the supply voltage (VDC)
Note: Although the signal conditioning circuit does have
integral over-current protection, it is recommended that
the circuit be protected with a 0.25 amp fuse.
Wiring Instructions:
(Refer to Illustrations 2 & 3)
1) Move the programmable jumper on the signal
conditioning board into the position closest to the
meter’s outlet, as shown in Illustration 3.
2) Connect the positive DC power source (+12 to +35
VDC) to terminal #1 on the DIN connector.
3) Connect terminal #2 of the DIN connector to the
positive current input on the receiving device.
4) If the power source does not originate from the
receiving device, the negative side of the power
supply must be connected to the signal ground of the
receiving device.
5) If the transmitter is operating properly, the green
LED on the signal conditioning board will illuminate
dimly at zero flow and will increase in intensity as
flow increases.
0-5 VDC output connections:
Wiring Instructions:
(Refer to Illustrations 4 & 5)
1) Move the programmable jumper on the circuit board
into the position closest to the meter’s inlet, as
shown in Illustration 5.
2) Connect the positive voltage source (+12 to +35
VDC) to terminal #1 of the DIN connector.
3) Connect terminal #2 of the DIN connector to the
negative side of the DC voltage source.
4) Connect terminal #3 of the DIN connector to the 0-5
VDC input of the receiving device.
5) If the power source does not originate at the
receiving device, a wire will need to be connected
between the negative side of the voltage source and
the signal ground of the receiving device.
6) If the transmitter is operating correctly, the green
LED on the circuit board will illuminate brightly when
power is applied to the unit.
Note: The input impedance (resistance) of the receiving
device must not be lower than 100 Ω or non-linearities
may result. Lower impedance will not damage the
transmitter.
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