Rockwell Automation Allen-Bradley 1794-IRT8K, User Manual

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Publication 1794-6.5.12 - September 2011
2
Overview of FLEX I/O and Your Thermocouple, RTD, and Millivolt Input Module
The FLEX system consists of an adapter module, terminal base unit, DIN rail,
power supply, and adapter cabling components. You can use up to 8 terminal
bases per adapter module.
For detailed instructions on how to set up and install your module, refer to the
topic, Install Your FLEX I/O Input Module, on page 7.
Types of Modules
The module refer to the following catalogs.
The module accepts up to 8 thermocouple or RTD inputs. The inputs are
nonisolated and are selected with analog multiplexers. The inputs accept
millivolt or resistive inputs. Default input spans are -40.00 mV… +100.00 mV
or 0.0…500.0
Ω
. Fault indicators are located on the field side.
No switches or jumpers are used on the TC and RTD Input module. The
inputs have both fixed hardware filters and selectable firmware digital filters.
What the FLEX I/O Input
Module Does
The module is a high-speed, high-accuracy temperature and millivolt
measuring module that accepts thermocouple inputs, 2-, 3-, and 4-wire RTD
inputs, and mV source inputs.
It offers the following:
• wire-off, over-range, and under-range detection
• good common mode rejection
• usage with long thermocouple wiring
• usage with grounded or ungrounded thermocouples
The Series B version of 1794-IRT8 provides capability to work with grounded
thermocouples.
Use cold junction compensators (cat. no. 1794-CJC2) in thermocouple mode.
Two cold junction compensators are shipped with the 1794-IRT8.
Catalog No. Voltage Inputs Description
1794-IRT8 24V DC 8 Analog – 8-pt, 16 bit non-isolated RTD,
thermocouple and mV Input module
1794-IRT8K 24V DC 8 Analog – 8-pt, 16 bit non-isolated RTD,
thermocouple and mV Input module.
Conformally coated module.
1794-IRT8XT 24V DC 8 Analog – 8-pt, 16 bit non-isolated RTD,
thermocouple and mV Input module designed
for extended temperature.