Lake Monitors FlowStat ES Sensor (Plastic) - Manual (Page 4)

4. It is recommended that the sensor be placed in such a position
that the round access cover can be removed for cleaning and tur-
bine servicing. It is also recommended that a union be placed
near the sensor to allow easy removal.
Note1: The FlowStat is a bi-directional measuring device.
References to “inlet” and “outlet” refer to uni-directional systems.
Installation - Electronic (4-20mA Only)
The FlowStat circuit is a two-wire loop-powered design that transmits a
4-20mA signal that is proportional to flow rate. The noise-immune cur-
rent transmission from the sensor can be routed with low cost two con-
ductor twisted-pair cable. The circuit operates on 12-35 V
DC and
requires a source capable of supplying at least 20mA of current. The
circuit has built in polarity protection and over-current limiting to protect
both the transmitter and what the transmitter is connected to.
1. Connect the red wire (pin 1 for units with the electronic disconnect
option) from the transmitter sensor to the positive 12-35 V DC
power supply output.
2. Connect the black wire (pin 2 for units with the electronic disconnect
option) from the transmitter to the positive side of the loop load
(resistor, chart recorder, data acquisition board, meter, etc.). This
connection may be labeled "4-20mA Input" or "4-20mA (+)" on
some devices.
3. If applicable, connect the negative side of the loop load to negative
side of the power supply.
4. Apply power to the system.
5. If everything is operating correctly, the green LED on the sensor
will dimly illuminate and 4mA will be flowing in the loop. If there is
fluid flowing through the sensor, the current will be higher than
4mA and the LED will be quite bright.
If the LED does not illuminate:
check wiring terminations for good connections
check wiring polarity
verify correct supply voltage
ensure that the load impedance is within allowable limits
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1. Relieve pressure in the piping system.
2. Remove the retainer ring that secures the turbine access cover.
3. Remove the access cover with a pliers, taking care not to damage
the o-ring seal.
4. Pull out the turbine assembly and the shaft.
5. Inspect the shaft for things that may have wrapped around it.
6. Inspect the turbine bearing surface for wear and elongation.
Replace as necessary.
7. Clean any rust off of the magnets that may have accumulated.
8. Reassemble the unit by placing the turbine into the body cavity
with the two magnet pockets facing inward. Place the shaft into the
turbine hole and guide it into the retaining hole in the body cavity.
Lubricate the o-ring seal with some glycerin or other lubricant and
press it into the pocket of the body. Replace the retaining ring
securely before applying pressure to the system.
Circuit recalibration (4-20mA version):
1. Place a milliamp meter into the current loop.
2. Turn off the flow going though the sensor. Adjust the OFFSET
control for a reading of 4mA on the milliamp meter.
3. Adjust the flow rate though the meter to full flow rate. Adjust the
SPAN control for a reading of 20mA on the milliamp meter. The
two controls are not interactive, so further adjustment should not
be necessary.
Circuit recalibration (0-5V DC version):
1. Place a voltmeter across the black & green wires of the sensor pigtail.
2. Turn off the flow going though the sensor. Verify a reading of less
than 50 mV DC on the voltmeter.
3. Adjust the flow rate though the meter to full-scale flow rate. Adjust
the SPAN control for a reading of 5 V DC on the voltmeter.
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