Product Summary
The 1785-L40C is a high-performance ControlNet processor from Allen-Bradley’s PLC-5 series. It provides 48 Kilowords of battery-backed SRAM and supports up to 2048 total I/O points. This module delivers rapid scan times and robust network communication, making it ideal for demanding industrial automation systems.
Why Choose the 1785-L40C for Your Control System?
Procurement managers require reliable, scalable controllers. The 1785-L40C meets these needs with its large memory and flexible I/O architecture. This processor handles both discrete and analog signals efficiently across multiple chassis.
Engineers appreciate the ControlNet hot backup option. The module supports the 1785-CHBM cartridge for system redundancy. This feature minimizes downtime during critical manufacturing operations.
The unit offers a user-selectable network update time from 2 to 100 ms. You can optimize throughput for high-speed applications. Its I/O transmission rate reaches 5 Mbps for fast data exchange.
Compatibility with 1771, 1794, 1746, and 1791 I/O modules simplifies system expansion. The processor also includes a control coprocessor expansion port. This allows advanced local processing without extra hardware.
Power draw is just 3.3A at 5V DC, keeping thermal dissipation low. The module dissipates 59 BTU/hour during operation. This efficiency reduces cabinet cooling requirements.
Technical Performance Review
The processor executes bit logic at 0.5ms per K-word and typical scan time at 2ms per K-word. These speeds ensure deterministic control loops for time-critical processes.
Environmental tolerance is excellent. The unit operates from 0 to 60 °C without derating. It withstands 30G operational shock and 1G vibration from 10 to 500 Hz.
Connectivity options include an RJ45 ControlNet port, a 25-pin D-shell serial port, and a 3-pin DH+ port. The serial port supports baud rates from 57.6 kbps to 230.4 kbps. You can set scan time per rack from 10ms to 3ms accordingly.
Battery-backed static RAM preserves program memory during power loss. An EEPROM backup option using 1785-ME16, -ME32, -ME64, or -M100 adds extra security. This protects your logic against data corruption.
The open-style enclosure simplifies installation in standard cabinets. At just 1.42 kg (3 lbs), the module is lightweight yet robust. All units carry UL, CE, CSA, and C‑TICK certifications for global deployment.
