IOtech MultiScan 1200, User Manual

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234 Chapter 14: System Calibration TempScan / MultiScan User's Manual
To Calibrate a Thermocouple Card for Cold-Junction Offset
CAUTION
CAUTION CAUTION
CAUTION
Ensure that the thermocouple scanning card has been calibrated for offset and
gain. If not, follow the thermocouple card offset and gain calibration procedures
as described in the previous text.
Cold-Junction Offset Calibration
1. Connect accurate thermocouple sources to the following multiple channels on the scanning card
being calibrated, where
chan
refers to the first channel number on the scanning card being
calibrated (refer to the previous table for valid cold-junction channel numbers).
•
TempTC/32B (for TempScan/1100):
chan, chan+4, chan+16, chan+20
•
TempTC/32A (for TempScan/1000A):
chan, chan+4, chan+16, chan+20
•
MTC/24 (for MultiScan/1200):
chan, chan+8, chan+16
Slide the scanning card into the previously-calibrated master chassis.
2. Power up the unit and wait at least one hour before continuing.
3. Apply the following temperature values in Celsius to the multiple cold-junction channels above:
•
TempTC/32B (for TempScan/1100):
nnn.n, ppp.p, qqq.q, rrr.r
•
TempTC/32A (for TempScan/1000A):
nnn.n, ppp.p, qqq.q, rrr.r
•
MTC/24 (for MultiScan/1200):
nnn.n, ppp.p, qqq.q