Overview
The Allen-Bradley 1746-INT4 is an isolated thermocouple and millivolt input module purpose-built for the SLC 500 platform. This 4-channel module provides independent analog input channels for thermocouple and low-level mV signal acquisition, making it ideal for temperature monitoring and process control in demanding industrial applications. Each channel is electrically isolated to prevent ground loop noise and cross-talk, ensuring reliable measurements even in environments with significant electrical interference.
Key Features
- Four isolated input channels: Each channel is isolated from the backplane and from each other, preventing electrical noise and cross-channel interference
- 16-bit resolution: Delivers high-precision analog-to-digital conversion for accurate temperature and voltage readings
- Multiple thermocouple support: Accommodates J, K, T, E, R, S, B, N, and C-type thermocouples plus ±100 mV DC millivolt signals
- Cold junction compensation (CJC): Automatic compensation ensures accurate temperature measurement independent of module temperature
- Built-in signal filtering: Optical coupling and filter circuitry reduce signal noise pickup
- Easy installation: Single-slot mounting in SLC 500 chassis with automatic I/O configuration
Technical Specifications
The 1746-INT4 operates with a backplane current consumption of 110 mA @ 5 V DC and 85 mA @ 24 V DC, with a maximum backplane power consumption of 0.6 W (0.55 W @ 5 V, 2 W @ 24 V). The module uses Sigma-Delta ADC modulation for robust analog conversion and can support temperature ranges up to -270°C to 1820°C depending on thermocouple type. It includes a green 18-position removable terminal block for field wiring. The module mounts in any SLC 500 chassis slot except slot 0 and automatically assigns the correct number of input words without requiring special I/O configuration.
Typical Applications
- Process temperature monitoring and control systems
- Industrial heat treat and kiln applications requiring multi-point thermocouple input
- Food and beverage processing with temperature-sensitive operations
- Pharmaceutical manufacturing with strict temperature validation requirements
- Machinery and equipment diagnostics where bearing or component temperature monitoring is critical
- HVAC and environmental chamber control systems
Compatibility & Replacements
Compatible With
- SLC 500 series programmable logic controllers
- SLC 5/01, 5/02, 5/03, 5/04, and 5/05 processors
- SLC 500 open-style and fixed-style chassis
- RSLogix 500 programming software
- Allen-Bradley communication systems and networks
Replaces / Drop-In Replacement For
- Previous revision levels of the 1746-INT4 (Series A and earlier)
Works With
- RSLogix 500 development and monitoring software
- SLC 500 ladder logic and structured text programming
- Allen-Bradley EtherNet/IP industrial network infrastructure
- Proprietary PLC-5 and CompactLogix systems via gateway modules
