Allen-Bradley 1746-IB16 | SLC 500 Digital Input Card, New Original

Description

Note: Many products are not yet listed. Please contact us for more product information. Our supply channels are constantly expanding, and we currently have 20 stable shared supply channels. Please confirm the model, product, price, and all other necessary information with customer service before placing an order. We offer new, refurbished, and used products, and prices are adjusted according to the year of the item you require.

3. Key Technical Specifications

4. Product Introduction

The Allen-Bradley 1746-IB16 is a 16-point 24V DC digital input module for the SLC 500 platform. It reads discrete field signals — pushbuttons, limit switches, proximity sensors, relay contacts, and selector switches — and passes the states to the SLC processor over the 1746 backplane. The module accepts 10–30V DC, so it covers both standard 24V DC control circuits and 12V systems without a separate card.

Two features make this module the one most SLC integrators reach for first. The sink/source wiring is selectable by how you land the common — you do not need a different part number for a sourcing sensor versus a sinking one. And the removable 20-terminal block means you can replace the module without pulling a single field wire. I have swapped these in live panels in under five minutes because the terminal block stays with the wiring.

Rockwell has moved the SLC 500 platform into a mature lifecycle phase, and the 1746-IB16 is no longer in active production. Every unit on the market now is surplus or refurbished inventory. That is the honest situation, and it changes what you should check before you buy.

1746-IB16

1746-IB16

1746-IB16

1746-IB16

5. Application Scenarios & Field Experience

Part 1 – Narrative Paragraph

The failure that hurts most on a digital input module is not a dead channel — it is a channel that reads on when the field device is off, or reads off when the device is on. I have seen a packaging line stop-start for three shifts because a limit switch input was reading 9V DC as a valid “on” state when the sensor was leaking. The module was fine. The input threshold was fine. The field wiring had a wet connection that was bleeding voltage through the input. When you replace a 1746-IB16, check the off-state voltage on every channel before you connect the new card. A module that reads correctly on the bench can still misread in a wet or noisy panel.

Part 2 – Numbered List (Application Scenarios)

1. Packaging Machinery – Sensor and Switch Inputs – The module reads proximity sensors on film registration, limit switches on sealing jaws, and pushbuttons on operator stations. The 8 ms response time handles the machine’s cycle without adding scan delay.
2. Material Handling – Conveyor Zone Detection – Used on SLC-controlled conveyor systems to read photo-eye and limit switch inputs across multiple zones. The single-slot width keeps the chassis compact on a line with dozens of I/O points.
3. Water Treatment – Pump Status and Valve Feedback – Reads run-status contacts from motor starters and end-of-travel switches on actuated valves. The 10–30V DC range covers both 24V DC control circuits and legacy 12V panels.
4. Machine Tools – Interlock and Guard Switch Inputs – Monitors guard door switches, E-stop contacts, and tool-present sensors. Sink/source flexibility lets one spare part cover panels wired either way.

Part 3 – Short Field Story

A bottling plant in the Midwest had an SLC 5/04 line that would fault intermittently on a conveyor zone. The crew had replaced the sensor twice and the input module once. The fault kept coming back. We asked them to measure the voltage at the module terminals with the sensor in the off state. It read 6.2V DC — above the module’s 5V DC off-state maximum. The module was correctly reading the leak as an input. The problem was a damaged cable with moisture in the jacket. They replaced the cable, and the module that had been pulled as “bad” tested clean on the bench. The input card had been telling the truth the whole time.

6. Standard Operating Procedure (SOP) for Quality Control

Every 1746-IB16 module passes this QC sequence:

• Visual & Origin Inspection – We verify the Allen-Bradley marking, the 1746-IB16 catalog number, and the date code. We inspect the edge connector for bent pins and the terminal block header for cracked plastic. A module with a damaged connector or evidence of moisture ingress is rejected.
• Revision Documentation – We read and photograph the full catalog number, the series letter, and the date code. That record ships with the module so you can compare it against the unit you are replacing.
• Chassis Fit Verification – Each module is seated in a 1746 test chassis to confirm the edge connector engages fully and the retention screw holds. A module that fits loosely will cause intermittent backplane faults.
• Input Channel Verification – We apply a calibrated DC voltage to each of the 16 inputs at 0V, 12V, and 24V. We verify the module reports off at 0V, on at 24V, and transitions correctly through the threshold. All 16 channels must pass.
• Off-State Leakage Check – We verify each channel reads off at 5V DC or below. A channel that reads on at the off-state maximum will cause false inputs in the field.
• Isolation Test – We apply 1500V AC between the field terminals and the backplane connector for 60 seconds. Leakage current must stay below the datasheet limit.
• LED Verification – We confirm each of the 16 point LEDs illuminates when its input is energized. A module with a dead LED passes the electrical test but gives the operator no field indication.
• ESD-Safe Packaging – The module is wrapped in anti-static film, seated in a conductive foam insert with the edge connector protected by a rigid shroud, and packed in a double-wall carton with static warning labels.

7. Frequently Asked Questions (FAQ)

Q1: What is the difference between the 1746- and the 1746-IV16?

A: Both are 16-point DC input modules, but they differ in voltage range and configuration. The 1746- is the 24V DC sink/source module with a 10–30V DC operating range. The 1746-IV16 is also a 16-point DC input but with a different voltage specification and wiring configuration. Check the catalog number on your existing module and match it exactly — the terminal wiring is not interchangeable without confirming the input type.

Q2: Can I use this module in a SLC 5/03 chassis that currently holds a different input card?

A: Yes, mechanically. The 1746 I/O modules all share the same form factor and edge connector. But you must update the processor’s I/O configuration to match the new module type, and the channel addressing will shift if the module type differs in point count. If you are replacing a 16-point card with a 16-point card of a different type, the addressing stays the same but the input filter and threshold behavior may differ.

Q3: What is the warranty on this module?

A: We offer a 12-month warranty from the ship date. It covers channel failure, threshold drift, backplane communication failure, and isolation breakdown under normal operating conditions. It does not cover damage from connecting field supply voltage directly to the backplane, ESD damage from handling without a wrist strap, or physical damage to the edge connector. Every module is tested on a live 1746 chassis before it ships.

Q4: Do you have this in stock?

A: The 1746- is out of active production and available only through surplus and refurbished channels. Stock varies week to week. Confirm availability before you plan an outage. If we are out, we will tell you what we actually have rather than quote a date we cannot hold.

Q5: Any installation pitfalls I should watch for?

A: Four. First, power down the chassis before inserting or removing the module — the 1746 backplane is not hot-swap capable. Second, record the field wiring and the common configuration before you pull the old module; the terminal block is removable but the wires are not labeled unless you label them. Third, verify the off-state voltage on every field device before you connect the new card — a leaking sensor or a wet connection will read as a false input and you will blame the module. Fourth, after the swap, verify each channel state in the processor’s data table before you return the line to production. A module that powers up is not necessarily reading correctly.