1746-IB16 Allen Bradley SLC 500 Digital Input Module | 16-Point I/O

Allen Bradley 1746-IB16 | SLC 500 Digital Input Module

The 1746-IB16 is a 16-point DC digital input module for the SLC 500 control platform from Allen Bradley. It receives discrete field signals and transfers their status to the controller through the backplane.

With a 10–30V DC operating range, this module supports compatible industrial switching devices. Its removable terminal block simplifies field wiring and module replacement during planned maintenance.

01 | Engineering Specifications

• Manufacturer: Allen Bradley
• Product Line: SLC 500
• Model: 1746-IB16
• Module Type: Digital DC Input Module
• Input Configuration: 16 current-sinking inputs
• Voltage Category: 24V DC
• Operating Voltage: 10–30V DC
• Maximum Signal Delay: 8 ms, ON or OFF
• Heat Dissipation per Point: 0.2 W
• Minimum Heat Dissipation: 0.425 W
• Total Heat Dissipation: 3.6 W
• Backplane Current at 5V DC: 50 mA
• Backplane Current at 24V DC: 0 mA
• Terminal Block: Removable, included
• Weight: Approximately 0.40 kg (0.88 lb)
• UPC: 662468067041

Specification note: The figures above follow the supplied product information. Confirm detailed electrical limits and wiring requirements against the applicable Allen Bradley documentation before installation.

02 | How the Module Works

The input channels monitor discrete field-device states. The controller reads these states through the SLC 500 backplane and uses them in the control program.

• Signal acquisition: Receives compatible DC switching signals from field devices.
• Controller interface: Transfers input status through the chassis backplane.
• Response timing: The stated maximum signal delay is 8 ms for ON or OFF transitions.
• Maintenance access: The removable terminal block supports easier wiring service.

Current-sinking terminology describes the input circuit's electrical configuration. Do not assume that every sourcing or sinking sensor is compatible. Check the field device's output type and the module's official wiring diagram first.

03 | Installation and Commissioning

1. Check the hardware: Verify the module number, chassis compatibility, and available slot.
2. Isolate the equipment: Follow plant lockout procedures before handling the module or field wiring.
3. Verify polarity: Confirm DC supply polarity and field-device wiring against the manufacturer's diagram.
4. Inspect the terminal block: Check connector seating and inspect terminals for looseness or corrosion.
5. Configure the controller: Confirm the correct SLC 500 I/O slot configuration and input addresses.
6. Test each channel: Operate the field device and compare its physical state with the controller input status.
7. Document the results: Record channel assignments, test results, and any wiring changes.

Field example: A conveyor fails to start because the controller does not recognize a limit switch. Measure the field signal, inspect the return path, and check the corresponding input status before replacing the module.

04 | Compatible Equipment and Applications

The 1746-IB16 suits compatible Allen Bradley SLC 500 installations that require discrete DC input monitoring.

• PLC systems: Compatible SLC 500 chassis and controller configurations.
• Material handling: Conveyor limit switches, position switches, and equipment interlocks.
• Manufacturing lines: Push buttons, selector switches, and machine status contacts.
• Packaging equipment: Guard switches, product detection signals, and cycle feedback.
• Water treatment: Discrete equipment status and compatible DC switch signals.
• Utilities and process plants: Pump status contacts and local equipment permissives.

Actual compatibility depends on the chassis, field voltage, output circuit, and wiring arrangement. This module handles discrete signals rather than continuous 4–20 mA measurements.

05 | Troubleshooting and Diagnostic Checks

• Input remains OFF: Measure the field signal and verify the return path, polarity, and terminal connections.
• Input remains ON: Check for a short circuit, incorrect common wiring, or a field device that stays active.
• Intermittent input: Inspect loose terminals, damaged conductors, electrical noise, and unstable field power.
• Incorrect input address: Verify the physical slot, controller configuration, and program addressing.
• Multiple channels fail: Check shared field power and common wiring before suspecting individual channels.
• Unexpected machine response: Compare the physical input, controller status, program logic, and output response.

The module supports discrete-state acquisition. Detailed fault identification depends on the controller diagnostics and available status indicators. Do not assume that it independently identifies every field wiring fault.

06 | Global PLC Spare HUB's Insight

In field maintenance, replacing a module without checking the signal path can waste time and leave the original fault unresolved.

For example, a packaging machine may report a missing guard-switch signal after maintenance. An engineer should check the switch, DC supply, common wiring, terminal connections, and controller input status in sequence.

If the correct electrical signal reaches the module but the controller still reports an incorrect state, inspect the slot configuration and module condition. Test the replacement under controlled conditions before returning the equipment to service.

Selection advice: Match the input voltage, channel count, electrical configuration, chassis compatibility, and required response time. If the application needs analog measurement or a different DC input circuit, select the appropriate module instead.

07 | Supply, Packaging, and Warranty

• Supplied Product: Allen Bradley 1746-IB16 digital input module.
• Packaging: Protective packaging suitable for international transportation.
• Warranty: 12-month warranty, subject to the seller's agreed terms.
• Dispatch: Typically within 24–48 hours after order confirmation and stock verification.
• Shipping Options: FedEx, UPS, and DHL, subject to destination and service availability.
• Quotation: Contact our sales team to confirm stock, condition, delivery cost, and lead time.

Packaging contents may vary by order. Confirm the inclusion of the removable terminal block and any additional accessories before purchase.

08 | Frequently Asked Questions

Q1: How can I distinguish a field wiring fault from an input module fault?

Measure the signal at the field terminals and compare it with the controller's input status. Check the common wiring and polarity first. If the electrical conditions match the official wiring requirements, continue with slot and module checks.

Q2: Will an 8 ms signal delay suit high-speed counting applications?

Not necessarily. Evaluate the complete input response and scan cycle against the required pulse duration. Use a suitable high-speed counter or dedicated input module when ordinary discrete inputs cannot capture the signal reliably.

Q3: What should I check when several input points fail simultaneously?

Inspect shared DC power, common wiring, connectors, and the chassis before testing individual channels. Multiple simultaneous failures often justify checking shared electrical conditions first, although the actual cause requires measurement.

Q4: Can I replace this module with another 16-point DC input card?

Do not select a replacement by channel count alone. Verify the complete catalog number, electrical configuration, chassis support, terminal arrangement, and controller compatibility. Confirm the substitute against official documentation before ordering.

Q5: What information should I provide when requesting a quotation?

Provide the full catalog number, required quantity, installation platform, delivery destination, and preferred shipping service. Include a photo of the existing label when available. These details help our team check compatibility, stock, and delivery options.

Request a Quote for Allen Bradley 1746-IB16

Need a replacement for your SLC 500 digital input system? Contact Global PLC Spare HUB to confirm the 1746-IB16 configuration, availability, warranty, and shipping options.

Send your part number and quantity to request a quotation.

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