Fluid Components International FLT Series Rack Mount User Manual
Page 15
FLUID COMPONENTS INTL
APPENDIX D - TEMP COMP
FLT
Series FlexSwitch
Rack Mount
D - 4
Doc. No. 06EN003250 Rev. N/C
Figure D-2. Sensing Element Calibration Connections
6.
Stop the process media flow and make sure that the media is at no flow and then let the instrument stabilize for
fifteen minutes.
7.
Record the resistance values of the sensing elements and calculate the resistance differential
(∆
R). If
∆
R does
not exceed the maximum
∆
R of 280 ohms then proceed with the calibration. If the
∆
R is above 280 ohms use
the next lower heater wattage setting and let the instrument stabilize. Recheck the
∆
R
8.
Start the process media flowing at the desired switch point velocity and at the low temperature, let the instrument
stabilize for fifteen minutes.
9.
Record the resistance values of the active and reference RTD's at the low temperature.
10. Raise the temperature of the process media to the maximum expected temperature. With the instrument power
on, let the instrument stabilize for fifteen minutes. The difference between the low and the high temperature
should not exceed 100 °F.
11. Record the resistance values of the active and reference RTD's for the high temperature.
12. Calculate the Temp Comp factor with the formula shown below.
TEMP
COMP =
∆
R Low Temperature -
∆
R High Temperature .
FACTOR (R Reference High Temperature) - (R Reference Low Temperature)
The Temp Comp factor is not to exceed
±0.041.
13. 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.
14. Look up the resistance values to adjust potentiometers 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.