Dwyer IEFS - Manual (Page 6)

Page 9
CONNECTIONS DIAGRAMS
Grounding Guidelines:
For best results, use a good quality earth ground, such as
metallic water piping or a driven ground, to ensure a good
connection to earth ground and good noise suppression.
For Metallic Pipe: For optimum connection, clamp wire to the
piping a short distance to one side of the flow sensor using an
electrical grounding clamp. Connect the wire to the earth ground
and to one of the housing screws, as shown in “Grounding
Diagram” below.
For Non-Metallic Pipe: Connect a wire from the housing screws
to a good earth ground, such as metalic water piping or a rod
driven into the ground.
Series IEFS & EFS2 meters are usually unaffected by moderate
levels of electrical noise. In some applications performance
may be improved by taking the following steps:
• Use shielded twisted pair cable (Belden 8723 or
equivalent above ground or Alpha 35482 or
equivalent burial).
• Clamp a ferrite bead (Steward 28A2029-OAO or
equivalent) on meter signal/power wire within 3/4”
of the meter strain relief (tape or tie wrap in place if
necessary). See diagram below.
• IMPORTANT - Connect the cable shield ground
wire to ground, ONLY at power supply end of cable.
General Electrical Guidelines:
• Whenever possible, avoid running control cables in
the same conduit with or bundled with AC power.
• Using shielded cable, be sure to connect shield to
ground at power supply end of the cable. Do not
connect other end of shield.
• Avoid routing flow sensor cables in close proximity to
a variable frequency drive.
• Recommended power and output wiring is shielded
twisted pair 18 to 22 AWG control cable.
• Recommended voltage is 12 to 24 VDC. Note that
unregulated power supplies can vary from nameplate
voltage by a considerable amount, especially with AC
line voltage fluctuation. Therefore 24V power supplies
must be regulated.
See the Connections diagrams on the following pages for the
appropriate terminals.
Power: A 12 to 24 Vdc power supply capable of at least 250
mA current output is needed.
Output: The standard output is pulses with flow in the forward
direction (Reverse flow output is optional (-RFO ). Electrically
it is an open collector opto isolated switch. The output is not
internally powered.
Note: This output is limited to 6 mA at 30 Vdc maximum.
COuNTER OR PLC
bAT 4 to 20 mA OuTPuT
Power
Forward Output
(open collector)
Reverse Output
( -RFO only)
12 to 24 VDC
Max. 6 mA, 30 VDC
Power
Forward Output
SERIES IEFS
SERIES bAT
SERIES IEFS
Sensor
4 to 20 mA
4 to 20 mA
24 VDC Power
Reverse Output
(-RFO only)
+
–
Max. 6 mA 30 VDC
*See Dual RTI Diagram for an
example of bidirectional connections.
FREquENCy
*See Dual RTI Diagram for an
example of bidirectional connections.
COuNTER OR PLC DIGITAL
INPuT
Page 8
ELECTRICAL CONNECTIONS
GROuNDING DIAGRAM
housing Screw
Earth
Ground
Grounding Clamp
24 VDC Power
PLACE FERRITE bEAD hERE
Metallic Pipe