CONFIGURATION AND CALIBRATION
CALIBRATING INPUTS
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15 December 1994
I-E96-301B1
®
slave module connected to an analog input signal. The type of
the input, as well as the zero and span in engineering units,
must also be specified to ensure proper scaling and corrections
for field calibration, cold junction compensation or nonlinearity
correction. Function code specifications also contain the A/D
resolution, lead wire resistance (if such a correction is desired),
and primary frequency of the noise to be rejected by each
input.
For cold junction compensation, the block which represents
the cold junction input must also be specified. To use the
slave’s on board cold junction reference, set specification 3 in
function code 215 to the block address of function code 215.
Any channel can be used as a remote cold junction reference
(in function code 216 specification 4, enter 1xx).
When an input channel is selected as a remote cold junction
reference, software smoothing of the input reading takes place.
This smoothing allows the temperature response of the remote
cold junction reference to closely match the temperature
response of the remote terminal blocks.
Each slave configured for a thermocouple input requires a cold
junction reference. Each slave can only have one cold junction
reference for up to 16 thermocouple inputs. The exception to
this is when one of the thermocouple inputs is used as a
remote cold junction reference.
Install one function code 217 block in the MFP configuration in
case slave tuning or field calibration operations are needed
later.
CALIBRATING INPUTS
Calibration is done at the factory and the calibration data is
stored on the slave in nonvolatile memory.
No calibration is
necessary.
If, however, field calibration is desired, use the pro-
cedure described in the field calibration instructions.
Field calibrate the IMASI03 slave with the MFP by tuning func-
tion code 217 which is described in
. It is necessary
to install function code 215 and one function code 216 for each
input channel in a configuration to field calibrate a slave. In
addition, when field calibrating a slave, the calibration type
defined in S4 of function code 217 must be consistent with the
input signal type defined in S4 of function code 216. Consider
the following examples.
Example 1
If calibrating a channel for millivolts or thermocouples, then S4
of function code 217 must be set to zero and S4 of function
code 216 must be set to any one of the millivolt or
