Fluid Components International FLT Series Rack Mount - Manual (Page 40)

Doc. No. 06EN003250 Rev. N/C 3 - 5 FLT  Series FlexSwitch  Rack Mount
CHAPTER 3 - OPERATION FLUID COMPONENTS INTL
Balance Adjustment
Under normal circumstances the control circuit balance procedure has been done by the factory. This procedure
needs to be done by the customer if the control circuit or the sensing element have been replaced, the sensing element
and control circuit are sent under separate cover, or extra cable is added between the control circuit and the sensing
element.
1. Extend the circuit card on the circuit card extender.
2. Turn off the heater (see Table 3-2 for jumper information). Turn ON the instrument power and adjust
potentiometer R3 (for CH. A) or R 49 (for CH.B) for a voltage of 0.0V ±2.0mV. For channel A the voltage is
between pins P1-D12 (+) and P1-B12 (-) or P2-1 (+) and P2-2 (-). For channel B the voltage is between pins
P1-D18 (+) and P1-B18 (-) or P2-6 (+) and P2-7 (-).
3. Turn OFF the power, return the heater(s) to normal and replace the circuit card in the slot.
Air/Gas Flow Applications
1. Ensure the configuration jumpers on the control circuit are correct for this application. (See Tables 3-2 through
3-6.)
2. Apply power to the instrument. Verify the yellow LED is on and allow the instrument fifteen minutes to warm-
up.
3. Verify the mode switch is in the RUN position.
4. Attach a DC voltmeter to the P1 connector with the positive (+) lead to pin P1-D12 and the negative (-) lead to
pin P1-B12; or the P2 connector with the positive (+) lead to pin P2-1 and the negative lead (-) to P2-2.
5. Establish the normal process flow condition and allow the signal to stabilize.
Note: The output signal will vary inversely with changes in the process flow rate. The output signal level is
relative to the type of process media being measured. (See Figure 3-3.)
6. Record the normal flow signal value.
Normal Flow Signal = ________ volts DC
7. Follow either the Detecting Decreasing Flow or the Detecting Increasing Flow procedure for each 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 2.000 volts and the no-flow signal is 5.000 volts, then the calculated set
point would be 3.500 volts.)
d) Record this value.
Calculated Alarm Set Point = ________Volts DC