FLT
®
Series FlexSwitch
TM
APPENDIX D - TEMP COMP
Fluid Components International LLC 93
POWER SUPPLY SETTINGS
FLT93S
3 Watts 1.75 Watts 0.75 Watts 0.21 Watts
Set For 18.0 Vdc Set For 13.8 Vdc Set For 9.0 Vdc Set For 4.9 Vdc
FLT93F
0.57 Watts 0.52 Watts 0.49 Watts 0.25 Watts
Set For 18.0 Vdc Set For 17.0 Vdc Set For 15.0 Vdc Set For 11.8 Vdc
Table D-1. Heater Voltage Settings
10. Raise the temperature of the process media to the maximum expected temperature. The difference between the low and the high tem-
perature is not to exceed 100 °F.
11. Set the flow rate to the same value used for the low temperature.
Note:
The flow rate must be the same at both the low and high temperature. For gases, the flow rate must be held constant in
terms of volumetric flow rate (SCFM, NCMH, etc.).
12. With the instrument power on, let the instrument stabilize for fifteen minutes.
13. Record the resistance values of the active and reference RTDs for the high temperature.
14. Calculate the Temp Comp factor with the formula shown below.
TEMP
COMP
FACTOR
=
R Low Temperature - R High Temperature
(R Reference High Temperature) - (R Reference Low Temperature)
The Temp Comp factor is not to exceed ±0.041.
15. If the Temp Comp factor is within tolerance, turn off the power to the instrument and stop the process media if needed. Disconnect the
DMM’s and the power supply from the instrument. Reconnect the sensing element wires to the control circuit socket and reinstall the
socket in the enclosure if it was previously removed. Do not pinch the wires between the socket and the enclosure.
16. Look up the resistance values to adjust potentiometers R5 and R8 in the Temp Comp Factor table (Table D-2). Follow the procedure in the
Restoring Temp Comp adjustment section using the values found in the table below.
17. If the calculated Temp Comp factor exceeds the allowable tolerance by a small amount (±0.01), using the maximum Temp Comp factor
may make the instrument perform satisfactorily. However, if the factor is out of tolerance by more than ±0.01 then it will be necessary to
repeat the calibration to verify the result. Continue with the adjustment procedure if the second result is within tolerance.
Figure D-1. Sensing Element Calibration Connections
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