TB 9-5855-1890-35
r. Connect digital voltmeter to 115 V ac power source, turn power on, and allow 15
minutes to warm up.
t. Energize TI and observe indication on digital voltmeter.
NOTE
If this is the initial calibration, adjust temperature controller
potentiometer R4 (fig. 1) for an indication of 4.30 0.05 V dc
on digital voltmeter.
NOTE
Deenergize TI immediately after performing u below.
voltmeter indication equal to previous offset voltage listed on TI offset voltage label
(located on temperature controller) 0.05 V dc. Record indication as Vo.
v. Set power switch to OFF.
w. Set offset voltage switch to ON.
x. Replace temperature controller cover plate but do not secure.
y. Close top access hatch of shroud. Set power switch to ON and record start time
and allow TI to warm up for 1 hour.
8. Calibration
a. Performance Check
NOTE
Short input connectors of differential voltmeter and adjust
zero indication on the .0001 null range, if necessary. Remove
short.
(1) Observe and record indication on differential voltmeter in microvolts.
(2) Using differential thermocouple set calibration data and indication on
differential voltmeter, calculate the temperature difference indication and record as ∆T.
If temperature difference is not between 4.05 oC and 4.95 oC, perform b below.
NOTE
Divide calibration factor, e.g., 40 V/C, into observed
differential voltmeter indication.
The result equals
differential temperature.
b. Adjustments
(1) Open access hatch on shroud and remove cover plate from TI temperature
controller.
CHANGE 1 7
