Allen-Bradley 1746-ITB16 – 5 V TTL 16‑Point Digital Input Module for SLC 500

The Allen‑Bradley 1746-ITB16 is a straightforward way to bring 5 V DC TTL-level signals into an SLC 500 system. From my experience, it’s the go‑to choice when you’re interfacing board‑level logic, test fixtures, or compact sensors that don’t run on 24 V. You might notice that it behaves like a standard 16‑point input card in the chassis, but with the lower input threshold and fast response that TTL applications typically need.

Company’s Order Placement Process and Guarantees

• Warranty: 365 days
• Lead time: 1 week if in stock; no more than one month at the latest
• Payment: 50% advance payment; full payment before delivery
• Express options: FedEx, UPS, DHL

Key Features

• 5 V DC TTL inputs (16 points): Ideal for low‑voltage logic from boards, fixtures, and TTL sensors.
• Fast signal response: Suited to applications where low latency is preferred over heavy filtering.
• Two commons (grouped 8+8): Makes it easier to split field wiring and isolate sections of a machine, which in many cases simplifies troubleshooting.
• Status LEDs per channel: Quick visual confirmation of input states during commissioning.
• 1746 backplane integration: Slot straight into a 1746 chassis and communicate over the SLC 500 backplane—no extra interface required.
• Standard 1746 RTB wiring: Uses the common 1746 removable terminal block (e.g., 1746‑TB16), which installers typically have on hand.

Technical Specifications

Application Fields

Typical uses include integrating TTL encoders or sensors from custom machine boards, capturing logic states from test benches and fixtures, or retrofitting legacy electronics where 5 V signals are standard. In packaging lines and electronics assembly, I’ve seen it used to monitor low‑voltage photoeyes, limit switches on PCB conveyors, and on small robotics where controller daughterboards expose TTL I/O.

Advantages & Value

• Right‑sized for TTL: Eliminates level shifters in many cases, cutting panel space and wiring time.
• Solid SLC 500 compatibility: Drops into existing 1746 chassis—good for fast service swaps and line uptime.
• Lower risk, predictable behavior: Status LEDs and grouped commons help isolate faults quickly.
• Procurement confidence: Widely supported in the market; spares are straightforward to source.
• Support components available: Matching RTBs (1746‑TB16), power supplies (1746‑P2), and chassis (1746‑A4/A7/A10) simplify stocking.

Installation & Maintenance

• Panel layout: Mount the 1746 chassis in a clean, ventilated cabinet; keep low‑level TTL wiring away from high‑noise VFD cables.
• Wiring tips: Use the 1746 RTB; label commons per 8‑point group. Maintain a stable 5 V reference from the field device.
• Grounding & shielding: For longer runs, shielded cable and a single‑point ground typically reduce chatter.
• Safety: De‑energize the chassis before inserting or removing modules; verify backplane power capacity.
• Routine checks: Inspect terminal tightness, clean dust quarterly, and verify input thresholds during periodic QA. Firmware isn’t applicable on this I/O card, so upkeep is mostly mechanical and wiring‑related.

Quality & Certifications

The 1746 family typically carries UL and CE marks and is designed for industrial environments. RoHS compliance may vary by manufacturing vintage for legacy SLC 500 modules; the product label or datasheet will confirm. Standard manufacturer warranty policies apply; our supply terms include a 365‑day warranty for your order.