FLT
®
Series FlexSwitch
TM
OPERATION
Fluid Components International LLC 25
For the appropriate alarm, determine whether the status LED is on or off (red for No. 1 or green for No. 2).
If the LED is on, turn the setpoint adjustment potentiometer (R26 for Alarm No. 1 or R25 for Alarm No. 2) slowly counterclockwise just
until the LED turns off.
OR
If the LED is off, turn the setpoint adjustment potentiometer (R26 for Alarm No. 1 or R25 for Alarm No. 2) clockwise until the LED turns on
and then slowly turn pot counterclockwise just until the LED turns off.
Continue With The Liquid Flow Applications Procedure
1. Move the Mode switch to the RUN position.
2. Establish the normal process flow condition. For low-flow alarm setups, observe that the status LED is off. For high flow alarm setups
observe that the status LED is on.
3. Establish the process alarm condition and monitor the voltmeter display.
4. When the output signal passes through the calculated setpoint value observe that the status LED should turns on for low-flow alarms or
off for high flow alarms, and that the relay contacts change state.
5. Reestablish the normal process flow condition. Observe that the LED and the relay contacts reset.
6. Disconnect the voltmeter from P1.
7. Replace the enclosure cover.
Note:
The alarm can be set for a specific flow rate. Follow the Liquid Flow Applications procedure up to step 7 except establish
the specific flow rate rather than the normal flow. The output signal will be the setpoint value. Determine whether the alarm
should actuate with decreasing or increasing flow and skip to the appropriate step 4 in Detecting Decreasing Flow or Detecting
Increasing Flow respectively. Enter the specific flow rate value as the setpoint. Then continue with the rest of the procedure.
The default relay logic configuration is for the relay coil to be de-energized when the flow signal voltage is greater than the
setpoint value; i.e., in a normal process flow condition the relay coil is energized if the alarm has been set for low-flow detec-
tion and de-energized if the alarm has been set for high flow detection. It is recommended to have the relay coils energized
when the process condition is normal. This lets the relay go into a fail-safe alarm state in case of a power failure.
Adjustment by Observation
Note:
The control circuit has two mutually exclusive alarms identified as Alarm No. 1 and Alarm No. 2. Each alarm has its own set-
point adjustment potentiometer and LED indicator. Each alarm can be set up for one of three applications: flow, level/interface,
or temperature. The following application specific adjustment procedures are generic and can be used for setting either or both
alarms. The mode switch must be in the RUN position. Use Figure 3-2 to help locate the adjustment potentiometers and LEDs.
Flow Applications
1. Ensure that the instrument has been properly installed in the pipeline. Fill the pipeline so the sensing element is surrounded by the
process medium.
2. Apply power to the instrument. Allow fifteen minutes for the sensing element to stabilize.
3. Flow the pipeline at the normal or expected rate. Remove the enclosure cover to access the control circuit for adjustments.
Detecting Decreasing Flow (Low Flow Alarm)
If the status LED is off, turn the setpoint adjustment potentiometer clockwise until the LED turns on. With the LED on, slowly turn the po-
tentiometer counterclockwise one turn past the point at which the LED just turns off. The potentiometer may have up to one-quarter turn of
hysteresis; therefore, if the mark is overshot, repeat the procedure.
Detecting Increasing Flow (High Flow Alarm)
If the status LED is on, turn the setpoint adjustment potentiometer counterclockwise until the LED turns off. With the LED off, slowly turn the
potentiometer clockwise one-half turn past the point at which the LED just turns on. The potentiometer may have up to one-quarter turn of
hysteresis; therefore, if the mark is overshot, repeat the procedure.
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