1746-IG16 | Allen-Bradley | Digital DC Input Module

Configured for TTL signal acquisition in SLC 500 control networks, the Allen-Bradley 1746-IG16 (1746-IG16 Digital DC Input Module) provides direct physical/electrical execution of logic-level monitoring for 5 VDC source devices.

Hardware Specifications

Profinet / EtherNet/IP Deterministic Networks

The 1746-IG16 integrates into the SLC 500 backplane, facilitating high-speed data acquisition for TTL or BCD compatible field devices. The module requires specific backplane bus communication velocity settings to maintain deterministic I/O scanning intervals. Users must ensure that the firmware flash compatibility of the SLC 500 processor supports the high-speed input polling cycle (0.25 to 0.5 ms signal delay). The I/O density scaling allows for high-channel utilization without exceeding the backplane current capacity; however, users should calculate the cumulative power draw when populating multiple slots to prevent bus voltage sag.

Frequently Asked Questions

Q: Does the 1746-IG16 module support hot-swapping during processor operation?

A: No. The 1746-IG16 does not support hot-swapping. The chassis must be de-energized to prevent electrical faults or damage to the backplane communication pins during module insertion or removal.

Q: How is the signal delay profile managed by the input filter?

A: The module offers selectable signal delay settings of 0.25 ms or 0.5 ms. These values define the debounce time before a high or low transition is registered by the processor, ensuring signal stability against transient noise.

Field Installation Guidelines

1. Power down the SLC 500 chassis and verify zero voltage at the backplane before installation.
2. Install the 1746-RT25B removable terminal block securely to ensure consistent contact resistance for all 16 input channels.
3. Utilize 1746-HT or 1746-HCA connectors for reliable I/O wiring, ensuring that the cable shields are properly terminated to the chassis ground to minimize electromagnetic interference (EMI).
4. Verify the 5 VDC source polarity before connecting external field devices to prevent damage to the input circuitry.
5. Perform a wiring continuity check to confirm that no short-circuit exists between the input signal and the chassis common.
6. Once installed, confirm the module status via the programming software and verify that the input status LED indicators map correctly to the expected logic state.