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Phone: +86 16626708626Description
Key Technical Specifications
| Parameter | Value |
|---|---|
| Catalog Number | 1785-ENET |
| Module Type | Ethernet Interface (Sidecar for PLC-5) |
| Ethernet Port | 1 × RJ45 (10/100 Mbps, auto-negotiate) |
| Protocol Support | TCP/IP, EtherNet/IP (application-level), PCCC/CSPv4 |
| Max Connections | 64 simultaneous TCP/IP connections |
| Unsolicited Definitions | 512 per module (used by RSLinx, HMI, etc.) |
| Backplane Current | 1.0 A @ 5 V DC (typical); up to 2.2 A under load |
| Power Dissipation | 5–11.5 W (varies by source) |
| Heat Dissipation | 17–39 BTU/hr |
| Chassis Compatibility | 1771 universal I/O chassis (second leftmost slot, attached to CPU) |
| Slot Width | Single slot |
| Operating Temperature | 0 to 60 °C (32 to 140 °F) |
| Storage Temperature | −40 to 85 °C (−40 to 185 °F) |
| Humidity | 5–95% non-condensing |
| Isolation Voltage | 500 V AC for 60 seconds (communication to system) |
| Supported Processors | Enhanced PLC-5 (Series B or later), Ethernet PLC-5, ControlNet PLC-5 |
| Software Support | RSLogix 5, RSLinx Classic, RSWho |
| Certifications | UL, CE, CSA (industrial use) |
Product Introduction
The Allen-Bradley 1785-ENET is a single-slot Ethernet interface module (sidecar) for PLC-5 processors in 1771 chassis. It provides a 10/100 Mbps RJ45 port for TCP/IP and EtherNet/IP application-level communications, enabling programming, HMI connections, and MSG-based data exchange with other controllers.
This module is chosen for adding Ethernet connectivity to legacy PLC-5 systems without replacing the entire controller. In field deployments, it’s commonly used for remote programming, SCADA integration, and peer-to-peer messaging where EtherNet/IP I/O scanning is not required.
1785-ENET
1785-ENET
Troubleshooting Quick Reference
| Symptom | Possible Cause | Relevance to this Part | Quick Check Method | Recommendation |
|---|---|---|---|---|
| No LINK LED on Ethernet port | Cable fault, switch port issue, or module not powered | ✅ High | Check cable continuity; verify switch port LEDs; measure 5 V DC at backplane | Replace cable or try different switch port; verify chassis power |
| Cannot ping over Ethernet | IP config mismatch or module not configured | ✅ High | Ping from PC; verify IP/subnet/gateway in RSLogix 5 Channel Config | Re-download channel config to processor; power cycle after config change |
| RSLinx shows module but no tags | Revision/firmware mismatch or protocol limitation | ✅ Medium | Check 1785-ENET series and revision; verify driver (CSPv4 vs EtherNet/IP) | Use correct RSLinx driver; ensure Series A Rev E or later for CIP MSG |
| MSG instructions fail between ControlLogix and | 1785-ENET revision too old for CIP stack | ✅ High | Verify 1785-ENET Series A revision (Rev B does not support CIP MSG) | Upgrade to Series A Rev E or later, or Series B/C; check CIP path syntax |
| intermittent comms or timeouts | Network congestion or grounding issues | ❌ Medium | Check network traffic; verify shield grounding on Ethernet cable | Reduce broadcast traffic; ensure single-point shield grounding |
| Module works after power cycle but fails later | Configuration not saved or thermal issue | ✅ Medium | Monitor module temperature; re-download config and verify | Improve chassis airflow; ensure config is saved and downloaded |
If you’re stuck, send photos of the module (series/revision), your channel config screenshot, and a short network diagram. We’ll review it before you swap the module.
Frequently Asked Questions (FAQ)
Q: Is the 1785-ENET hot-swappable?
A: No. The 1785-ENET is a sidecar module that must be installed and removed with chassis power OFF. Hot-swapping can damage the processor or sidecar connector.
Q: Which processors work with the 1785-ENET?
A: Enhanced Series B or later, Ethernet , and ControlNet processors. It attaches to the side of the CPU and uses channel 3A for communication.
Q: What’s the difference between 1785-ENET Series A, B, and C?
A: Series A (early revisions) may not support CIP MSG for ControlLogix communications. Series B and C add improved protocol support and email client functionality. For MSG between ControlLogix and , use Series A Rev E or later, or Series B/C.
Q: Can I use the 1785-ENET for EtherNet/IP I/O scanning?
A: No. The 1785-ENET supports application-level communications (MSG, programming, HMI) only. It does not perform cyclic I/O scanning like ControlLogix EtherNet/IP modules.
Q: What condition are these modules in, and why is pricing lower than factory?
A: We sell New Original (New Surplus) and Refurbished (tested) units. Pricing is lower because these are surplus or professionally refurbished, not current factory production. Each refurbished unit goes through live functional testing and comes with a 1-year warranty.
Q: Do I need to reconfigure the module when replacing a failed 1785-ENET?
A: Yes. The channel configuration is stored in the processor, not the module. When swapping, download the channel config to the processor and power cycle the chassis for settings to take effect.
Q: Can I use the 1785-ENET with ControlLogix for MSG communications?
A: Yes, but only with 1785-ENET Series A Rev E or later, or Series B/C. Early Series A Rev B modules do not support the CIP protocol stack required for ControlLogix MSG.
