Fluid Components International FLT Series - Manual (Page 24)

FLUID COMPONENTS INTL CHAPTER 3 - OPERATION
FLTÔ Series FlexSwitchÔ 3 - 6 Doc. No. 06EN003246 Rev. B
Detecting Increasing Flow (high flow alarm)
1. Establish the excessive process flow condition and allow the signal to stabilize.
2. Record the high flow signal. (The high flow signal should be less than the normal flow signal.)
High Flow Signal = ________ volts DC
3. Determine the set point by calculating the average of the normal and high flow output signals. (i.e., If the
normal signal is 2.000 volts and the high flow signal is 1.000 volts, then the calculated set point would be 1.500
volts.)
4. Record this value.
Calculated Set Point = ________ volts DC
Note: The calculated set point must be at least 0.020 volts less than the normal signal to ensure that the alarm will
reset.
5. Slide the mode switch to the CALIBRATE position.
6. Adjust the calibrate potentiometer (R24) until the voltmeter equals the calculated set point.
7. 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 set point 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 set point adjustment potentiometer ( R26 for alarm No. 1 or R25 for alarm No. 2)
clockwise until the LED turns on and then slowly counterclockwise just until the LED turns off.
Continue With the Air/Gas Flow Procedure
1. Slide the mode switch to the RUN position.
2. Establish the normal process flow condition. For low-flow alarm setups, the status LED should be off. For high
flow alarm setups, the status LED should be on.
3. Establish the process alarm condition and monitor the voltmeter display.
4. When the output signal passes through the calculated set point value, the status LED should turn on for low-flow
alarms, off for high flow alarms, and the relay contacts should change state.
5. Reestablish the normal process flow condition. Both the LED and the relay contacts should 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 Air/Gas Flow Application procedure up to step 7
except establish the specific flow rate rather than the normal flow. The output signal will be the set point
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, respectfully. Enter the
specific flow rate value as the set point. Then follow the Continue With the Air /Gas Flow Procedure steps.
The relay logic default configuration is set for the relay coil to be de-energized when the flow signal voltage
is greater than the set point value. (i.e., Assume that the normal process flow condition has been
established. In this state, the relay coil will be energized if the alarm has been set for low-flow detection
and de-energized if the alarm has been set for high flow detection.) A recommendation is to have the relay
coils energized when the process condition is normal. This will enable the alarm to close or open the
contacts in case of a power failure.