Allen-Bradley 1785-L80C ControlNet PLC-5/80C Processor

Product Introduction

The 1785‑L80C programmable controller belongs to the trusted PLC‑5 series from Allen‑Bradley. This processor module is specifically built for ControlNet networks, enabling fast and deterministic communication with distributed I/O, variable‑speed drives, and operator interfaces.

With a generous 100‑kiloword user memory and support for up to 3072 total I/O points, the 1785‑L80C handles complex automation tasks with ease. Its battery‑backed static RAM preserves your program during power outages, while optional EEPROM cartridges (such as the 1785‑ME16, ‑ME32, ‑ME64, or ‑M100) offer convenient backup without requiring a permanent power source.

This controller mounts directly into a 1771 I/O chassis and works with intelligent, 8‑point, 16‑point, and 32‑point I/O modules. It also supports three addressing modes (2‑slot, 1‑slot, and ½‑slot), giving you flexibility when organizing your system layout.

Technical Specifications

The 1785‑L80C delivers robust processing power for mid‑to‑large applications. Its program scan time is just 0.5 ms per K word for bit logic, and 2 ms per K word for other instructions. The internal clock/calendar keeps accurate time with a variation of only ±5 minutes per month at 60 °C.

For communication, the controller provides:

• One RS‑232‑C / RS‑422‑A / RS‑423‑A port for programming and general‑purpose serial links.

• A dedicated ControlNet Network Access Port (NAP) with RJ‑45 connector, running at 5 Mbps.

• Support for DH+ and remote I/O networks at selectable baud rates: 57.6 Kbps, 115.2 Kbps, or 230.4 Kbps.

The I/O scan time varies by baud rate – 10 ms at 57.6 Kbps, 7 ms at 115.2 Kbps, and 3 ms at 230.4 Kbps. You can connect up to 93 I/O chassis in total, with a maximum of 32 remote chassis per I/O link. Additionally, the ControlNet network supports 99 nodes with repeaters, and cable lengths up to 1000 m (with 2 nodes) or 250 m (with 48 nodes). With repeaters, the maximum link length extends to 6000 m for two nodes.

The module also includes a control coprocessor expansion port, enabling future upgrades or specialised functions. For hot backup applications, you can install the 1785‑CHBM hot backup cartridge alongside the 1785‑L80C.

Mechanical & Environmental Ratings

This controller operates reliably in demanding industrial environments. It requires a backplane current of 3.3 A at 5 V DC and dissipates up to 59 BTU/hour under full load. The unit is rated for:

• Temperature: 0 to 60 °C (32 to 140 °F) – no derating needed.

• Relative humidity: 5‑95 % (non‑condensing).

• Vibration resistance: 2G at 10‑500 Hz.

• Shock resistance: 30G operational shock.

These specifications are validated through IEC testing, and the product carries CE, UL, CSA, and C‑TICK certifications, confirming its compliance with international standards.

Installation and Mounting

Installing the 1785‑L80C is straightforward. Simply insert the module into any available slot of a 1771 I/O chassis. Ensure the backplane power supply can deliver the required 3.3 A at 5 V DC. For memory backup, you can add a 1770‑XYC battery module or one of the battery‑backed memory cartridges (1785‑ME32, ‑ME64, or ‑M100) to protect your program data.

When connecting to ControlNet, use standard coaxial cables with the RJ‑45 NAP port or connect via the network’s trunkline. Remember to set the node address and baud rate correctly before powering up. The controller’s open‑style enclosure suits panel mounting; however, always observe the specified temperature and humidity limits for optimal long‑term performance.

Packaging List

Your shipment for the 1785‑L80C includes the following items:

• One 1785‑L80C ControlNet PLC‑5/80C processor module.

• One battery (installed) for memory backup.

• One user manual quick‑start guide (paper or digital).

• One warranty card (terms apply).

Note: Cables, programming software, and I/O modules are sold separately.
Shipping method: FedEx, UPS, or DHL (carrier selected at checkout).

Frequently Asked Questions (FAQ)

1. Can the 1785‑L80C replace a 1785‑L80B or 1785‑L80E?
Yes, the 1785‑L80C is designed for ControlNet networks. It is not directly interchangeable with the ‑L80B (DH+ only) or ‑L80E (Ethernet) without network adjustments, but the processor core is similar.

2. What memory backup options are available for the 1785‑L80C?
You can use the internal battery‑backed RAM, or add an EEPROM cartridge (e.g., 1785‑ME64) for non‑volatile program storage. A 1770‑XYC battery module also provides extended backup time.

3. How many I/O points can the 1785‑L80C handle?
It supports a maximum of 3072 total I/O – either as a mixed configuration or 3072 inputs plus 3072 outputs in complementary mode. This covers both digital and analog signals.

4. Does the 1785‑L80C support hot backup?
Yes. When you install the optional 1785‑CHBM hot backup cartridge, the 1785‑L80C can operate in a redundant pair for critical processes.

5. What software do I need to program the 1785‑L80C?
Allen‑Bradley’s RSLogix 5 (version 3.0 or later) is the primary programming package. Ensure you have the correct communication drivers for the serial or ControlNet port.