Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | 1756-IC16 |
| Manufacturer | Allen-Bradley (Rockwell Automation) |
| Product Type | ControlLogix Digital DC Input Module |
| Series | ControlLogix 1756 |
| Input Channels | 16 (2 groups of 8) |
| Input Voltage Category | 48V DC sink |
| Operating Voltage Range | 30–60V DC (30–55V DC @ 60°C) |
| Isolation | 250V continuous between groups of 8 inputs |
| Terminal Block | 20-pin; 1756-TBNH or 1756-TBSH |
| Communication Format | Input Data / CST Timestamped Input Data |
| Filter Times (DC) | OFF→ON: 0, 1, 2 ms; ON→OFF: 0, 1, 2, 9, 18 ms |
| Diagnostic Features | Open wire, field power loss detection |
| Country of Origin | Malaysia |
| Lifecycle Status | Active |
| Standard Warranty | 1 year |
Main Features and Advantages
The 1756-IC16 addresses a specific niche within the ControlLogix ecosystem: applications requiring discrete input acquisition at 48V DC rather than the standard 24V DC. This voltage capability allows the 1756-IC16 to interface directly with field devices and control circuits that operate at 48V DC, eliminating the need for interposing relays or voltage level conversion. For system integrators working with legacy equipment or industry-specific standards that mandate 48V DC signaling, the 1756-IC16 provides a native, backplane-integrated solution that preserves signal integrity and reduces panel complexity.
The group-isolated architecture of the 1756-IC16 is a meaningful safety and reliability feature. With 250V continuous isolation between the two 8-point groups, the module prevents fault propagation from one group to the other, which is particularly valuable in applications where the two groups interface with different field circuits or where one group may be exposed to higher transient activity. This isolation design also contributes to noise immunity, reducing the likelihood of spurious input state changes in electrically noisy industrial environments .
For applications requiring precise event sequencing, the 1756-IC16 supports Change-of-State (COS) timestamping when configured with the CST Timestamped communication format. This capability allows the module to record the coordinated system time of input transitions, enabling accurate reconstruction of event sequences in diagnostic and root-cause analysis workflows. The module also provides configurable digital filter times per group of eight points, allowing users to tune input response to match the electrical characteristics of connected field devices—short filter times for fast-responding sensors, longer times for mechanical contacts that may exhibit bounce .
Application Field
The is deployed in industrial control applications where 48V DC discrete signals are the native field interface standard. In material handling and conveyor systems, the module interfaces with photo-eyes, limit switches, and proximity sensors that operate at 48V DC, providing the ControlLogix controller with position and presence feedback for sortation and routing logic. The 16-channel density of the allows a single module to handle multiple conveyor zones, reducing slot count and backplane overhead compared to lower-density alternatives.
In electrical power and substation automation, the serves as an interface for status monitoring of 48V DC control circuits, including breaker position indications, relay status contacts, and auxiliary contact feedback. The group isolation feature is particularly relevant here, as the two input groups may interface with circuits at different potentials or in different equipment bays. Telecommunications and data center infrastructure also employ the for monitoring 48V DC power distribution systems, where it captures status signals from rectifiers, battery monitoring units, and distribution panels .
Legacy system modernization projects frequently specify the when migrating older PLC platforms that used 48V DC input cards, allowing the existing field wiring and sensor infrastructure to be retained while upgrading the control platform to ControlLogix. The module’s active lifecycle status and availability through Rockwell Automation distribution ensure that the can be specified for new builds and spares inventory with confidence in long-term supply chain support.
