19
"t
.
" - TC INPUT CHECK
1) The display will show "t." and the two most
significant digits of the measurement alternately
with the remaining digits as shown in the
following figure:
The "tH" calibration is correct if the indication
shown is equal to "t.30" and "000" + 10 counts.
1) Check the zero calibration, by setting the
calibrator to 0.000 mV, the read-out must be
equal to "t. 0" and "000" + 10 counts.
2) Check the half scale linearity by setting the
calibrator to 25.000 mV. The read-out must be
"t.15" and "000" + 10 counts.
NOTE
: when it is desired to use a different
check point, the following formula describes the
ratio between the signal input and the
instrument read-out (in counts).
Instrument readout (in counts) =
input value
50 (mV)
30000
•
3) If linearity is incorrect, repeat thermocouple
calibration.
4) Push FUNC pushbutton, the instrument will go
to the next calibration group.
COLD JUNCTION CALIBRATION
NOTE
: make sure that "tL" and "tH" parameters
are correctly calibrated before "rJ" parameter
calibration.
rJ - ACTUAL VALUE
The display will show "rJ.F" (where "F" means
"OFF").
1) Measure the temperature close to terminals 2
and 3 using an instrument with accuracy better
than 0.1 °C (see Fig. 13).
Fig. 13
2) Wait for a few minutes to allow the temperature
to stabilize over the entire system (sensor,
calibrator and instrument).
3) Using
▲
or
▼
push-button, set a value equal to
the temperature measured by the measuring
device in a tenth of °C.
4) Start the calibration by pushing the FUNC
pushbutton. Only the decimal point of the last
significant digit will light to indicate that the
controller is performing the calibration routine.
At the end of this calibration routine, the
controller will go to the next calibration step.
Check symbol MSD (in counts)
remaining three digits
2
+
_
3
RTD
Measuring
device
1601-1-0C.p65
5/2/00, 1:45 PM
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