Allen-Bradley 1756-IRT8I

Technical specifications

Manufacturer

Allen-Bradley

Manufacturer part no.

1756-IRT8I

Type

Analog input module

Application

I/O module

Used with

ControlLogix 1756 chassis

Inputs

Eight isolated channels - Any combination of RTD or Thermocouple mode, Two CJC sensors for Thermocouple use. The CJC sensors, product catalog number 1756-CJC, do not come with the module. You must order the sensors separately.

Thermocouple types

B, C, D, E, J, K, N, R, S, T, TXK/XK (L)

Thermocouple linearization

ITS-90

Current draw @ 5.1V

200 mA

Current draw @ 24V

150 mA

Total backplane power

4.6 W

Voltage and current ratings

Backplane: 5.lV DC, 200 mA, 24V DC, l50 mA, Input: 1...4000 Ohms, +/—l00 mV, Thermocouple; B,C,E,J,K,R,S,T,N,D,L

Power dissipation, max

4.6 W(15.7 BTU/hr)

Thermal dissipation

15.7 BTU/hr

RTD excitation current

600 µA

Open circuit detection time

Thermocouple input and 3-wire RTD input = 2 s 4-wire RTD input = 5 s

Overvoltage protection, max

±30V DC

Normal mode noise rejection

75 dB at 60 Hz

Channel bandwidth

Notch filter configuration dependent, See publication 1756-UM540 for possible values.

Calibrated accuracy @ 25 °C

0.05%

Module error over full temperature range

0.1%

Local CJC sensor accuracy

± 0.3 °C

Module input scan time, min

1 ms

Data format

IEEE 32-bit floating point

Module conversion method

Sigma-Delta

Isolation voltage

250V (continuous), reinforced insulation type, inputs to backplane 250V (continuous), basic insulation type, input to input, Compliant and tested according to IEC/UL 61010-1

Thermocouple Type B

21…1820 °C (68…3308 °F) 293…2093 °K 528…3768 °R

Thermocouple Type C

0…2320 °C (32…4208 °F) 273…2593 °K 492…4668 °R

Thermocouple Type E

-270…+1000 °C (-454…+1832 °F) 3…1273 °K 6…2292 °R

Thermocouple Type J

-210…+1200 °C (-346…+2192 °F) 63…1473 °K 114…2652 °R

Technical documents (1)

• Rockwell Automation technical data 1756-TD002

Key features

• Eight isolated channels, any combination of RTD or thermocouple mode
• Thermocouple linearization to ITS-90
• Two CJC sensors for thermocouple use, ordered separately
• Electronic module keying, software configurable
• Calibrated accuracy of 0.05% at 25 °C

About the Allen-Bradley 1756-IRT8I

The 1756-IRT8I is a ControlLogix 8 point RTD / ohms / thermocouple / mV input module (36 pin), with each of its 8 isolated points configured separately. It draws 200 mA at 5.1V and 150 mA at 24V, 4.6 W of backplane power in total. Conversion is Sigma-Delta and data is IEEE 32-bit floating point.

What is the 1756-IRT8I used for?

It reads temperature sensors into a ControlLogix system, with any combination of RTD or thermocouple mode across its eight isolated channels. Thermocouple use needs two CJC sensors, catalog number 1756-CJC, ordered separately.

Lifecycle and successor

Active (Rockwell Automation lifecycle status, checked 24 October 2026).

Before you order

What to photograph or confirm so the right unit is quoted.

Read the catalog number 1756-IRT8I, the series letter and the firmware revision from the label. Send us a photo of the label and we confirm the match before we quote.