Fill-Rite TM Series Precision Meter - Manual (Page 9)

When powered through an approved barrier, Reed Switch
sensors are Intrinsically Safe.
Trouble Shooting the Sensor
CAUTION: Do NOT use an Ohm-meter to test
the
reed switch sensor (pulser).
Remove the sensor from the flow meter, and expose the
red & black leads. This can be done at a convenient junc-
tion, or at the register.
 Measure the voltage between the red & black leads. It
should be equal to the voltage provided by the register.
 Pass a magnet across the tip of the sensor, the voltage
should switch to zero (less than 0.2 V).
If the magnet cannot activate switching of the sensor, then
the sensor has failed and must be replaced. There are no
alignment requirements for the Reed Switch sensor.
1 . 9
Reed Switch
This sensor is strictly for use with battery powered stand
-alone registers, where no external power source is avail-
able. If external power is available, Hall Effect pulser
should be used - even when the register is battery pow-
ered.
In so called ‘pulse meter’ service, either Hall Effect or
Quadrature Hall Effect pulser must be used - depending
upon the requirements of the receiving instrument.
The Reed Switch sensor (pulser) consists of a set of con-
tacts, hermetically sealed in a glass tube, protecting the con-
tacts from dirt and corrosion of the the outside world. Con-
tacts are actuated by an external magnetic field, provided by
permanent magnets inside the rotors.
This is a mechanical device with a finite life. To extend pulser
life, flow meters with Reed Switch pulser are only available in
‘low resolution’ version.
When the pulser starts to wear out, it rarely fails instantly.
Instead it starts to miss pulses. We recommend that the flow
meter be recalibrated on a regular basis. Once pulser failure
is detected, establish a schedule for pulser replacement as a
matter of normal maintenance.
Contact Rating:
 Volts DC max. : 30 VDC
 Amps DC max. : 0.01 A
 Watts DC max. : 0.25 W
 Initial resistance : 1.0 Ώ
 Operating Temp range : -40ºF/+300ºF (-40ºC/+150ºC)
 D-Must operate : 0.125” (3.2 mm)
 D-Must release : 0.400” (10.2 mm)
 Cable specifications:
24 AWG, foil shield & drain wire, blue PVC jacket, RoHS.
75VDC. Capacitance: 185 nF/km. Inductance: 0.65 mH/
km.
Standard with 18” (45 cm) leads. 120” (305 cm) optional.
BLACK
RED
Optional Sensors (pulsers)