3
Signet 5500 Flow Monitor
+
-
-
+
-
+
Relay 1
Relay 2
NC
C
NO
NC
C
NO
NC
C
NO
NC
C
NO
Device
A
External AC/DC
power
Device
B
5500
Terminals
Relay
De-energized
Relay
Energized
7. Relay
Connections
Two internal relay contact sets (COM, NO, and NC) may be used
for external device control. Front panel LED annunciators indicate
the activation status of each relay. Each relay can control up to two
devices simultaneously, as shown. Relay operation modes include
Low alarm, High alarm, Pulse, and Totalizer (sec. 8.5).
Common device connections include:
• Pulse mode - metering pump control
• Pulse mode - solenoid valve control
• Low or High mode - warning lamps
• Low or High mode - bells or sirens
• Low or High mode - external heavy-duty relay
Wiring Example Right
Device A IS powered when relay 2 is de-energized (front panel
LED "off"). Power is discontinued when the relay 2 setpoint is
reached (front panel LED "on"). Device B IS NOT powered when
the relay 2 is de-energized. Power is applied after the relay 2
setpoint is reached.
6. 4 to 20 mA Current Output Connections
(sec. 8.4)
+
-
4-20
mA
5500
Terminals
-
+
4
20
mA
*
Fuse**
1/8A
Technical Notes:
** 1/8 A fuse recommended (customer supplied)
* 4-20 mA output is internally powered (non-isolated), maximum
loop impedance 350
Ω
with a 12 V instrument supply voltage,
950
Ω
with a 24 V instrument supply voltage.
To isolate output and prevent ground loop problems:
1. Use monitor device with isolated inputs, or
2. Use separate DC supply for 5500 and monitor device, or
3. Power 5500 with 12 - 24 VAC step-down transformer.
1 2
Total
reset
5500
Terminals
Momentary pushbutton switch
5. Totalizer Reset Connections
(sec. 8.3)
Technical Notes:
• Use 2-conductor shielded twisted pair cable for reset lines up to
30 m (100 ft) max.
• External reset switch overrides software security feature
(section 9.3 I).
• To reduce the possibility of AC noise interference, isolate AC
power lines from reset lines.
Technical Notes:
• Maximum relay contact ratings:
5 A @ 30 VDC,
5 A @ 125 VAC, or
3 A @ 250 VAC
• An external heavy-duty relay must be used for devices with surge
or operating currents that exceed the above speci
fi
cations.
