Allen-Bradley 1746-IB16 SLC 500

SKU: 1746-IB16 Category: PLC Brand: Allen-Bradley

Description
Additional information

The Allen-Bradley 1746-IB16 is a 16-point DC input module belonging to the SLC 500 modular I/O system, manufactured by Rockwell Automation (Allen-Bradley). It is designed to interface field-level discrete DC input signals with the SLC 500 programmable logic controller platform. The module occupies one slot in any SLC 500 modular chassis and is compatible with the full range of SLC 500 processors.

The 1746-IB16 accepts 16 individual 24 V DC sinking (IEC Type 1) input signals, providing electrical isolation between field devices and the backplane logic. Each input channel features an LED status indicator for real-time diagnostics. The module communicates directly over the SLC 500 backplane and requires no external power supply for logic operation, drawing its logic power from the chassis power supply. Input filtering is built in to suppress noise and contact bounce, and the module meets IEC 61131-2 Type 1 input specifications.

The 1746-IB16 is widely deployed in discrete manufacturing, material handling, packaging machinery, and process control applications where 24 V DC field devices such as proximity sensors, limit switches, and pushbuttons must be interfaced to a PLC. Its compact single-slot form factor and high channel density make it suitable for both new installations and retrofit projects within existing SLC 500 systems across industries including automotive, food and beverage, and general manufacturing.

Technical Specifications

Number of Inputs	16
Input Voltage (Nominal)	24 V DC
Input Voltage Range	10–30 V DC
Input Type	Sinking (IEC Type 1)
Input Current (Nominal)	8 mA at 24 V DC
ON State Voltage Minimum	10 V DC
OFF State Voltage Maximum	5 V DC
ON State Current Minimum	5 mA
OFF State Current Maximum	1.5 mA
Isolation	1500 V AC (field side to backplane)
Input Filter Time	1 ms (hardware)
LED Indicators	16 x input status LEDs
Backplane Current Draw	75 mA at 5 V DC
Operating Temperature	0 °C to 60 °C
Storage Temperature	-40 °C to 85 °C
Relative Humidity	5–95% (non-condensing)
Certifications	UL, CSA, CE, C-Tick
Mounting	SLC 500 modular chassis (1746 series)

Common Fault Codes

Fault Code 01: Module configuration mismatch — the module type in the chassis does not match the configuration stored in the processor.
Verify the module type and slot assignment in RSLogix 500. Re-download the processor configuration after correcting the I/O configuration table.
Fault Code 02: I/O chassis communication fault — the processor has lost communication with the module in the specified slot.
Check chassis backplane connections and module seating. Reseat the module firmly in the chassis slot and cycle power. Inspect the chassis backplane for damage.
Fault Code 04: Module hardware fault — the module has detected an internal hardware failure.
Replace the 1746-IB16 module. Verify that chassis power supply voltage is within specification before installing the replacement module.
Major Fault Type 7: I/O fault — a major I/O fault has been declared by the processor due to an unrecoverable module error.
Identify the faulted slot using RSLogix 500 fault routine. Clear the fault via the fault routine or processor keyswitch cycle. Inspect and replace the affected module if the fault persists.
Fault Code 10: Rack fault — communication to the I/O rack containing this module has been interrupted.
Check all chassis interconnect cables and power supply status. Verify that the chassis power supply is providing correct 5 V DC backplane voltage.
Fault Code 20: Inhibited module — the module slot has been inhibited in the processor configuration, preventing I/O updates.
In RSLogix 500, navigate to the I/O configuration and remove the inhibit setting for the affected slot, then re-download the program.
Fault Code 83: Illegal module in slot — an unrecognized or incompatible module has been detected in a configured slot.
Confirm that the installed module part number matches the configured module type. Replace with the correct 1746-IB16 module if necessary.

Frequently Asked Questions

What input voltage does the 1746-IB16 accept?

The 1746-IB16 accepts 24 V DC nominal input signals, with an operating range of 10 to 30 V DC. It is designed for sinking (IEC Type 1) DC input configurations.

Is the 1746-IB16 compatible with all SLC 500 processors?

Yes, the 1746-IB16 is compatible with all SLC 500 modular processors including the SLC 5/01, 5/02, 5/03, 5/04, and 5/05. It fits in any slot of a 1746 series modular chassis.

Does the 1746-IB16 require an external power supply?

The module draws its logic power from the SLC 500 chassis backplane (75 mA at 5 V DC) and does not require a separate external logic supply. However, the field-side 24 V DC supply must be provided externally to power the connected input devices.

How many input channels does the 1746-IB16 provide?

The module provides 16 discrete DC input channels, each with an individual LED status indicator for local diagnostics.

What programming software is used to configure the 1746-IB16?

The 1746-IB16 is configured using Rockwell Automation RSLogix 500 software. The module is added to the I/O configuration table within the project and requires no special configuration beyond slot assignment and module type selection.

Troubleshooting

Input channel LED is illuminated but the corresponding bit in the input image table does not update in the processor.

Check the processor program scan and verify the I/O configuration in RSLogix 500. Confirm the module is not inhibited and that the slot address in the ladder logic matches the physical slot location.

Correct the slot addressing in the I/O configuration and ladder logic. Remove any inhibit setting on the module slot. Re-download the program and cycle processor power.

All 16 input LEDs remain off even when field devices are energized.

Measure the 24 V DC field supply voltage at the module's input terminal block. Verify wiring polarity and confirm the common (0 V) terminal is correctly connected.

Restore the 24 V DC field supply to within the 10–30 V DC operating range. Correct any wiring errors at the terminal block, ensuring the DC common is connected to the module's common terminal.

Intermittent or erratic input signal readings on one or more channels.

Inspect field wiring for loose terminations, damaged cable insulation, or excessive cable length causing noise pickup. Check the input device output voltage under load to confirm it meets the ON state minimum of 10 V DC.

Re-terminate all field wiring connections at the module terminal block. Add shielded cable or route signal cables away from power conductors. Replace any field device that does not meet the minimum ON state voltage requirement.

Processor declares a major I/O fault referencing the slot containing the 1746-IB16.

Use RSLogix 500 to read the fault code and identify the specific slot. Reseat the module and inspect the backplane connector pins for damage or contamination.

Reseat the module firmly and clear the major fault using the processor keyswitch or fault routine. If the fault recurs, replace the 1746-IB16 module and verify the chassis power supply output is within specification.

Module configuration mismatch fault occurs after replacing the module.

The replacement module part number may differ from the originally configured module, or the I/O configuration in the processor has not been updated to reflect the new module.

Verify the replacement module is the correct 1746-IB16 part number. In RSLogix 500, confirm the I/O configuration table matches the installed module type and re-download the configuration to the processor.

Condition	Repair, Used, Refurbished, New in box (sealed)