DC Input Modules | Allen-Bradley 1756-IC16

The Allen-Bradley 1756-IC16 is a 16-point discrete DC input module designed for the ControlLogix automation platform. It features a 48V DC sink configuration divided into two 8-point groups, offering reliable sensor signal acquisition with configurable electronic filtering and robust channel isolation.

Technical Specifications

Functional Design and Hardware Configuration

The 1756-IC16 occupies a single slot in a ControlLogix chassis and interfaces with field devices via a 20-position Removable Terminal Block (RTB). Compatible RTB housing options include the 1756-TBNH (screw-clamp) and 1756-TBSH (spring-clamp) variants. The module supports electronic keying to prevent incorrect module placement in a configured chassis slot.

Input Filtering and Timing Characteristics

Input delay and filtering parameters can be tailored to suppress electrical noise and transient signals in industrial environments. The OFF-to-ON transition combines a fixed 1 ms hardware delay with a selectable filter time of 0 ms, 1 ms, or 2 ms. The ON-to-OFF transition incorporates a 4 ms hardware delay alongside configurable filter times of 0 ms, 1 ms, 9 ms, or 18 ms.

Isolation and Environmental Ratings

The module provides basic insulation with a continuous isolation voltage rating of 250V from inputs to the backplane, and 125V from input group to input group. Note that individual inputs within the same group share common electrical reference points without channel-to-channel isolation. Operating voltage limits scale with ambient temperature conditions, maintaining a 30 to 60 VDC range up to 55 °C, which derates to 30 to 55 VDC at the maximum operating temperature of 60 °C.

Frequently Asked Questions

Q: What removable terminal blocks are compatible with the 1756-IC16? A: The module requires a 20-position RTB housing, specifically either the 1756-TBNH screw-clamp or 1756-TBSH spring-clamp terminal block.

Q: How does ambient temperature affect the operating voltage range? A: At 55 °C or below, the operating voltage range is 30 to 60 VDC. When operating at an elevated ambient temperature of 60 °C, the voltage range derates to 30 to 55 VDC.

Q: What is the channel grouping structure of this module? A: The 16 inputs are organized into two groups of 8 points each, sharing group-level isolation properties.