Rockwell Automation Publication 1756-RM011A-EN-P - June 2016 17
Hardware Specifications and Considerations Chapter 3
In general, if in the 6-channel module RPI is less than RTS, adjustments can be
made in the 6-channel Emulation module configuration to achieve the same
performance. Keep in mind that if RPI is less than RTS your performance in
Emulation mode is faster than it was as a 6-channel module.
In general, if in the 6-channel module RPI is greater than RTS then no
adjustments are necessary in the 6-channel Emulation module configuration to
achieve the same performance.
Cold Junction Compensation
on Thermocouple Modules
ControlLogix® thermocouple modules use cold junction compensation (CJC)
sensors. You must order the senors separately by ordering catalog number
1756-CJC, which consists of two CJC jumpers.
All CJCs for all 1756 Rockwell Automation® thermocouple modules are
electrically the same. The modules use a precision thermistor, but not all CJCs
can physically fit in all RTBs so you cannot substitute different CJCs from
different modules.
If you are using a 1756-IT6I or 1756-IT6I2 module with thermocouples and
are not using Remote CJC Compensation, be sure to order a 1756-CJC sensor
for the 1756-IRT8I RTB. The1771 thermocouple modules do not always use a
CJC resistor that is electrically compatible with 1756 modules.
Using an External Loop
Supply with the
1756-IF6CIS Module
The 1756-IF6CIS module can be used to supply loop power to an end device.
The module can simplify wiring and reduce the cost of installation by
eliminating the need for an external loop supply. While the 1756-IF6CIS
module typical case can be to supply loop power, the 1756-IF6CIS module can
still be used with an external loop supply on one or more channels. If one or
more of your 1756-IF6CIS channels uses an external loop supply, then you
must add some additional logic to your program to accommodate those
channels with an external loop supply.
IMPORTANT If you change the RPI of an 8-channel module on a ControlNet network, you
need to reschedule the network, which requires that the process be placed in
Program mode.
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