3. Feed ambient compensated mV corresponding to 80 % of FS.
The display should show corresponding temperature. If the
displayed temperature is incorrect turn the potentiometer marked
'SPAN' to display correct reading (CW to increase & CCW to
decrease).
o
eg.: Cr - Al thermocouple - Ambient compensated mV for 800 C
o
o
at ambient temp 30 C will be mV corresp. to 800 C (33.277 mV)
o
minus mV corresponding to 30 C (1.203 mV) = 32.074 mV
Repeat steps 2 and 3 to get zero error at both calibration points.
8.2)
Pt - 100 input ( 3 wire system)
1. Remove the Pt - 100 from its terminals and connect a resistance
decade box with 3 wire system in its place.
2. Feed resistance corresponding to 20 % value of FS (eg.resistance
o
o
corresponding to 20 C for 0 to 100 C range) The display should
show corresponding temperature. If the displayed temperature is
incorrect turn the potentiometer marked 'ZERO' to display correct
reading. (CW to increase and CCW to decrease)
3.
Feed resistance corresponding to 80 % value of FS (eg. resistance
o
o
corresponding to 80 C for 0 - 100 C range). The display should
show corresponding temperature. If the displayed temperature is
incorrect adjust the potentiometer marked 'SPAN' to display
correct reading. (CW to increase and CCW to decrease).
Repeat steps 2 and 3 to get zero error at both calibration points.
Check the calibration of the instruments every six months.
In case of error recalibrate using certified calibrators only.
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