Micromod MOD: 30ML Functions Data Base Reference - Manual (Page 136)

MOD 30ML Functions
CONFIGURATION EXAMPLES
3.3.12 COLD JUNCTION COMPENSATION (CJC) COMPOUND
This compound provides a cold junction compensated thermocouple signal which can be
used as the process variable input in a PID temperature control loop and for display and
recording purposes. An optional feature of this compound permits display of the measured
cold junction temperature at the instrument terminal block. The CJC compound can be
incorporated in strategies configured for either MOD 30ML or MODCELL instruments. Use of
the CJC compound requires that the instrument be equipped with the following hardware:
• 2013A Thermocouple Input Module:
This module accepts the millivolt field input signal from the thermocouple at the process
measurement point. One module is required for each thermocouple input.
• 2009AZ10240A RTD Input module with 2-Wire CJC Sensor:
This module accepts the temperature compensation signal from the RTD sensor connected
to the cold junction at the instrument terminal block. A single RTD module and sensor
provide compensation for all installed thermocouple input modules.
3.3.13 Configuration Overview
The CJC compound has two options: Option 1 provides only the compensated thermocouple
input. Option 2 provides the same compensated thermocouple input, and also makes the
temperature at the cold junction on the instrument terminal block available for display. Both
options are included when the compound is loaded into a strategy, Figure 3-39. The option
to which connections are made becomes the active option.
Figure 3. 39. Cold Junction Compensation Compound Blocks
3-42