Product Overview
The 1785-L46C15 is a powerful PLC-5/46C processor from Allen-Bradley. It offers protected memory and 48 kilowords of user memory. This controller supports ControlNet networks for fast data exchange. It handles up to 2048 forcible I/O points and 48000 nonforcible analog I/O. The module fits into a 1771 I/O chassis. Its backplane current draw is 3.3 A at 5 V DC.
Designed for harsh environments, it operates from 0 to 60 °C. The unit tolerates 30 G shock and 1 G vibration. It carries UL, CE, CSA, and C-TICK certifications. The 1785-L46C15 includes a battery-backed static RAM for program backup. You can also use EEPROM modules for additional backup.

Application Scenarios
This processor works well in manufacturing lines and process control. It suits applications needing high I/O counts and remote rack support. The ControlNet port enables redundant network configurations. You can connect up to 99 nodes per link with repeaters. The controller also supports DH+ and remote I/O communications.
Typical uses include assembly machines, packaging systems, and material handling. It also fits in oil and gas, water treatment, and chemical plants. The protected memory prevents accidental program overwrites. This feature adds security for critical processes.

Technical Specifications
- Processor: PLC-5/46C with ControlNet
- Max User Memory: 48 kilowords (32K per data-table file)
- Max Total I/O: 2048 forcible (any mix) or 2048 in + 2048 out (complementary); 48000 nonforcible
- Max Analog I/O: 2048 forcible, 48000 nonforcible
- ControlNet Speed: 5 Mbps
- Remote I/O Scan: 10 ms at 57.6 kbps, 7 ms at 115.2 kbps, 3 ms at 230.4 kbps
- Backplane Current: 3.3 A at 5 V DC
- Thermal Dissipation: 59 BTU/h
- Ports: 1 RS-232-C/422-A/423-A, 1 coprocessor expansion, 2 three-pin DH+/RIO
- Weight: 1.42 kg
The 1785-L46C15 supports up to 60 remote I/O chassis. It also allows up to 125 I/O chassis total. You can use half-slot, single-slot, or double-slot addressing. The module keys to the chassis with pins 40/42 and 54/56.
Installation & Maintenance Guide
Install the 1785-L46C15 into a 1771 chassis. Ensure correct keying for the slot. Use only 5 V DC from the backplane. Connect ControlNet cables to the BNC port. For DH+ or remote I/O, use the three-pin ports. Set the node address via dip switches.
Maintain the battery to preserve memory. Replace it every year or when the alarm lights up. Clean the module with a dry cloth only. Do not expose to conductive dust. Keep the operating temperature below 60 °C. Use proper grounding for the chassis.
Packing List
- 1 x 1785-L46C15 PLC-5/46C processor
- 1 x Battery pack
- 1 x User manual (digital download)
Shipping is via FedEx, UPS, or DHL. We pack each unit in anti-static foam. Your order ships within 24 hours.























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