Red Lion TCU - Manual (Page 91)

APPENDIX “E” - CALIBRATION
Calibration Check
The instrument has been fully calibrated at the factory for all thermocouple
and RTD types. If the unit appears to be indicating or controlling incorrectly,
see
Troubleshooting, page 78, before attempting this procedure.
If the controller is suspected of reading incorrectly, the instrument may be
checked for indication accuracy without disturbing the factory calibration.
The five parameters to be checked are: mV reading, thermocouple cold
junction temperature, RTD ohms reading, and linear DC output and Second
Input. The following procedures may be used for this purpose.
Note: Allow ½ hour warm-up with the controller in an upright position to allow
adequate ventilation to the case before checking these parameters.
mV Reading Check
1. Place the input sensor selection jumper in the TC position.
2. Connect a DC mV source with an accuracy of 0.01% or better to terminal #9
(+) & #10 (-).
3. Select the controller to indicate linear mV (lin), in Configure Input
Parameters.
4. Compare the controller read-out to the standard at various points over the
range (-5.00 mV to 54.00 mV). The tolerance is 0.15% of reading ± 1 LSD.
5. Calibrate the controller if the readings are out of tolerance.
Thermocouple Cold Junction Temperature Check
1. Place the input sensor selection jumper in the TC position.
2. Place a reference temperature probe in immediate vicinity of terminal #9 &
#10.
3. Install a shorting wire to terminals #9 & #10.
4. With thermocouple type t selected, compare controller read-out with a
calibrated probe. Allow sufficient time for temperatures to equalize. The
tolerance is
± 1°C.
5. Calibrate the cold junction temperature if out of tolerance.
RTD Ohms Reading
1. Place the input sensor jumper in the RTD position.
2. Connect RTD simulator to terminals #8, #9, & #10 (with an accuracy of 0.1
ohm or better).
3. Select the controller for linear ohms (rLIn) read-out, in Configure Input
Parameters.
4. Compare the controller read-out with the RTD simulator at various points
over the range 0.0 to 300.0 ohms. The tolerance is 0.15% of reading ±
1LSD.
5. Calibrate the controller RTD ohms if out of tolerance.
Linear DC Output Check
4 to 20 mA
1. Connect an ammeter to the linear output (#11 & #12) with an accuracy of
0.1% or better.
2. Set “ANAS” (Analog Assignment) to “INP”, in Configure Input
Parameters.
3. Drive the input signal level below the programmed “ANLO” value. Check
for 4 mA ( ± 0.02 mA).
4. Drive the input signal level above the programmed “ANHI” value. Check
for 20 mA ( ± 0.03 mA).
5. Calibrate the controller linear DC output if out of tolerance.
0 to 10 VDC
1. Connect a voltmeter to the linear output (#11 & #12).
2. Set “ANAS” (Analog Assignment) to “INP”, in Configure Input
Parameters.
3. Drive the input signal level below the programmed “ANLO” value. Check
for 0 VDC ( ± 20 mV).
4. Drive the input signal level above the programmed “ANHI” value. Check
for 10 VDC ( ± 30 mV).
5. Calibrate the controller linear DC output if out of tolerance.
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