Allen-Bradley 1756-IRT8I Thermocouple Input Module

The Allen-Bradley 1756-IRT8I ControlLogix eight-channel isolated analog input module is designed for temperature sensing in ControlLogix systems. Each of its eight inputs can be independently configured as RTD, thermocouple, or millivolt, with galvanic isolation between channels and from the backplane to improve noise immunity in industrial environments. The module includes two cold-junction compensation (CJC) sensors for thermocouple measurements and uses 36-pin signal connections. RTD support includes common sensors such as 100, 200, 500, and 1000 ohms (Pt sensors) as well as Ni 100/120 and Cu 10 ohm options, with selectable RTD ranges of 1–500 Ω, 2–1000 Ω, 4–2000 Ω, or 8–4000 Ω and 24-bit resolution (0.06–0.50 mΩ per count depending on range). Thermocouple inputs accept signals in the -100 to 100 mV range with 24-bit resolution, enabling precise temperature computation when paired with the module’s CJCs. As a part of the ControlLogix ecosystem, the 1756-IRT8I plugs into the 1756 backplane and provides eight isolated points for accurate temperature measurements across process control, manufacturing, and lab environments where robust temperature sensing is essential.