Product Summary
The 1785-L40C15 ControlNet PLC5 processor delivers 48K words memory and 2048 I/O points in any mix. It offers dual ControlNet ports plus DH+ and RIO for flexible distributed control. Engineers trust this rugged module for hot backup systems and demanding industrial applications.
Expert Technical Evaluation & Performance Review
The 1785-L40C15 operates with a bit-logic scan time of 0.5 ms per K word, ensuring fast program execution. Its typical scan is 2 ms per K word. The processor’s maximum user memory reaches 48 Kilowords, stored in battery-backed static RAM. This memory retains data via the 1770-XYC battery, which must be replaced while the processor has active power.
The module supports both forcible analog I/O up to 2048 points and nonforcible up to 48000 points. ControlNet I/O scans take 0.5 ms average per rack. Universal remote I/O scans vary from 10 ms at 57.6 kbits/s to 3 ms at 230.4 mbits/s. This performance suits high-speed material handling and process control lines.
Built-in communication ports include serial (DF1/ASCII), Data Highway Plus, Remote I/O, and two ControlNet channels. The dual ControlNet ports enable hot backup configuration using the 1785-CBHM cartridge. This setup provides high-speed processor switchover and data transfer for redundant architectures.
The 1785-L40C15 uses 2-slot, 1-slot, or 1/2-slot hardware addressing. It mounts in a 1771-series chassis (models A1B, A2B, A3B, A3B1, A4B) in the leftmost slot. It supports Bulletin 1771, 1794, 1746, and 1791 I/O modules (8, 16, 32-point, specialty, and intelligent). This wide compatibility simplifies integration with existing Allen‑Bradley systems.
Maximum total I/O chassis is 125, with up to 60 universal remote chassis. Extended local chassis count is 0, meaning all remote I/O must be over the network. The control coprocessor expansion port is present, allowing additional processing power. Protected memory is not supported, so program backups rely on EEPROM modules (1785-ME16/32/64/M100).
Product Procurement & Buyer Guide
Procurement engineers must confirm the processor’s memory and I/O requirements. The 1785-L40C15 offers 48K words memory, which fits mid‑size applications. For applications needing more than 2048 I/O points, consider higher‑memory PLC‑5/80 models. The unit requires a 1770‑XYC battery for RAM retention; stock spares to avoid data loss during power outages.
The dual ControlNet ports support hot backup, critical for high‑availability lines. Ensure the system includes the 1785‑CBHM cartridge in each rack for redundancy. The module accepts memory modules (1785-ME32/64/M100) to expand user memory. Order the correct memory module based on your program size.
Verify the chassis model: the 1785-L40C15 fits only in 1771‑series chassis with left‑most slot mounting. If you use 1794 Flex I/O or 1746 SLC I/O, confirm the network adapter compatibility. The serial port supports DF1 and ASCII for point‑to‑point programming. For networked communications, DH+ and ControlNet offer high‑speed data exchange with multiple devices.
Stock the 1770‑XYC battery and a 1785‑ME16 or larger EEPROM module for backup. The processor does not have protected memory, so regular backups are essential. When ordering replacement units, verify the catalog number matches 1785‑L40C15 exactly to ensure correct firmware and port configuration.
Logistics & Standard Packaging Details
Express delivery shipping is available via FedEx, UPS, and DHL. Contact our sales team for bulk order lead times and international shipping options.
