Allen-Bradley 1756-IB16I/K Digital DC Input Module

The Allen-Bradley 1756-IB16I/K, also cataloged as the 1756-IB16I/K Digital DC Input Module, serves as the primary 1756-IB16I/K DigitalDC Input module utilized to execute 16-channel discrete signal acquisition across ControlLogix platform architectures. The module converts 10–30 VDC field input states into backplane-serialized digital data words for controller scan processing.

Channel-level electrical separation is implemented across sixteen individually isolated inputs, allowing independent state evaluation prior to ControlLogix backplane aggregation.

Suffix Breakdown & Model Matrix

The 1756-IB16I/K is a single catalog-defined hardware configuration. No additional order code segmentation or functional suffix matrix is defined in the provided dataset. No structural decomposition is applied.

Hardware Specifications

ControlLogix Backplane Communication and I/O Execution Behavior

The module communicates through ControlLogix backplane cyclic scheduling, where I/O data is transferred via deterministic slot-based arbitration. Input state updates are synchronized with controller task execution cycles through internal backplane bus timing rather than external field protocol processing.

Profinet / EtherNet/IP connectivity is implemented at controller network level, while the module itself operates as a backplane-resident discrete acquisition node. I/O density scaling is fixed per chassis slot, with module mapping defined during system initialization.

Firmware compatibility is enforced through ControlLogix chassis revision matching, where module recognition is dependent on backplane enumeration during power-up sequence. Backplane communication velocity and scan alignment govern update consistency across cyclic execution windows.

Frequently Asked Questions (FAQ)

Q: Does the 1756-IB16I/K support mixed ON/OFF delay filtering per channel?
A: Yes. Each channel supports configurable filter timing options, with ON delay up to 2 ms and OFF delay selectable up to 18 ms, applied at hardware input processing stage before backplane transmission.

Q: What is the impact of cyclic update time on input sampling?
A: Cyclic update time ranges from 200 us to 750 ms depending on controller scan configuration, defining the refresh interval of input state data transferred into ControlLogix memory.

Q: Can backplane power variation affect module operation?
A: The module operates with 100 mA at 5.1 VDC backplane current and 3 mA at 24 VDC auxiliary consumption. Voltage instability outside chassis specification may cause input state invalidation during scan cycles.

Field Installation Guidelines

Install the module in a compatible ControlLogix chassis with stable backplane power distribution. Ensure full engagement of RTB or IFM connectors to maintain all 16 isolated input channels.

Maintain separation between DC input wiring and high-frequency switching conductors to reduce induced coupling across isolated signal paths. Shield termination should be implemented at a single-point grounding structure within the control cabinet.

Verify channel configuration mapping in ControlLogix programming environment prior to energizing field inputs. Avoid mixing unrelated voltage reference groups across adjacent terminals to preserve channel isolation integrity.