Fluid Components International FLT Series Rack Mount - Manual (Page 45)

FLUID COMPONENTS INTL CHAPTER 3 - OPERATION
FLT  Series FlexSwitch  Rack Mount 3 - 10 Doc. No. 06EN003250 Rev. N/C
Note: The output signal will vary inversely with changes in the process flow rate. The output signal level is
also relative to the type of process media being measured. (See Figure 3-3.)
5. Establish the normal process flow condition and allow the signal to stabilize.
6. Record the normal flow signal value.
Normal Flow Signal = ________ volts DC
7. Follow either the Detecting Decreasing Flow or Detecting Increasing Flow procedure for each Liquid flow
application alarm.
Detecting Decreasing Flow (low flow alarm)
a) Stop the process flow and allow the signal to stabilize.
b) Record the no-flow signal. (The no-flow signal should be greater than the normal flow signal).
No-Flow Signal = ________ volts DC
c) Determine the set point by calculating the arithmetic mean of the normal and no-flow output signals.
(i.e.; If the normal signal is 0.080 volts and the no-flow signal is 0.300 volts, then the calculated set
point would be 0.190 volts.)
d) Record this value.
Calculated Set Point = ________ volts DC
Note: The calculated set point must be at least 0.020 volts greater than the normal signal to ensure that the
alarm will reset.
e) Slide the mode switch to the CAL position.
f) Adjust the calibrate potentiometer R27 (below the CAL pot) until the voltmeter equals the calculated
set point.
g) For the appropriate alarm, determine whether the status LED is on or off (red for alarm 1 or green for
alarm 2).
1) If the LED is off, turn the set point adjustment potentiometer ( R30 for alarm 1 or R29 for
alarm 2) slowly clockwise just until the LED turns on.
2) If the LED is on, turn the set point adjustment potentiometer ( R30 for alarm 1 or R29 for
alarm 2) counterclockwise until the LED turns off and then slowly clockwise just until the
LED turns on.
Detecting Increasing Flow Rate (high flow alarm)
a) Establish the excessive flow condition and allow the signal to stabilize.
b) Record the high flow signal. (The high flow signal should be less than the normal flow signal.)
High Flow Signal = ________ volts DC
c) Determine the set point by calculating the arithmetic mean of the normal and high flow output signals.
(i.e.; If the normal signal is 0.080 volts and the high flow signal is 0.030 volts, then the calculated set
point would be 0.055 volts.)
d) Record this value.
Calculated Set Point = ________ volts DC
Note: The calculated set point must be at least 0.015 volts less than the normal signal to ensure that the alarm
will reset.