Allen-Bradley 1785-L80E Ethernet PLC-5 Processor

Allen-Bradley 1785-L80E Ethernet PLC-5 Processor

Configured for complex logic execution and data routing in plant automation networks, the Allen-Bradley 1785-L80E (1785 Ethernet PLC-5 Processor) provides direct physical/electrical execution. It handles up to 3072 maximum total I/O points and coordinates data transfer via embedded Ethernet, Data Highway Plus (DH+), and remote I/O serial interfaces, supporting a 3.3 A backplane current load and 100 KWords of user memory mapping.

Hardware Specifications

Deterministic Ethernet Network and I/O Density Scaling

The 1785-L80E architecture is built to support maximum I/O density scaling while maintaining deterministic packet delivery across its integrated communication layer. The module manages simultaneous data polling across up to 64 Universal Remote I/O chassis utilizing the DH+ protocol, while the dedicated onboard Ethernet port handles higher-level supervisory data block transfers. The internal ASIC routes heavy backplane bus communication velocity requests without interrupting the primary logic scanning matrix, ensuring 10 ms rack scan times at 57.6 kbits/s load thresholds.

Frequently Asked Questions

Q: What are the EEPROM program backup hardware requirements for the 1785-L80E?

A: Non-volatile program backup requires the installation of compatible EEPROM modules, specifically the 1785-ME16, 1785-ME32, 1785-ME64, or 1785-M100.

Q: How is the RS-232/422A serial port configured for physical communication?

A: The embedded serial interface hardware can be configured via switch settings to support RS-232-C, RS-422-A, and RS-423-A electrical standards for direct connection to ASCII devices or control coprocessors.

Q: Does the processor support hot-swapping under power?

A: No, insertion or removal of the 1785-L80E processor module while backplane power is applied can result in electrical arcing and memory corruption. The chassis power supply (e.g., 1771-P4S) must be de-energized prior to handling.

Field Installation Guidelines

1. Verify that chassis power is completely disconnected before attempting physical insertion of the module.
2. Align the printed circuit board edges with the top and bottom chassis guides in the leftmost slot of the 1771 I/O chassis.
3. Slide the module straight in until the backplane connectors firmly seat. Apply even pressure to the top and bottom ejector clips to lock the module into position.
4. When utilizing the embedded Ethernet and DH+ ports, ensure all cables are properly shielded. Tie the cable shield to the grounding stud on the local chassis bare metal to suppress transient electromagnetic interference.
5. Connect the 1770-XYC lithium battery to the dedicated terminal block on the processor module prior to logic loading to prevent static RAM loss during power cycling.