A standard 100 Mbps Ethernet hub worked on one DL205 network, so a hub can be compatible; that result does not guarantee every hub, PLC interface, or network layout will work. Before replacing hardware or changing settings, confirm the actual Ethernet interface and the speed and duplex supported by every connected device.
Stop swapping parts before checking the link
When a new connection does not come up, replacing the hub or repeatedly restarting devices is a tempting first move. Neither action identifies whether the problem is physical link, speed and duplex compatibility, addressing, or the network layout. The reported DL205 installation was being wired up; it did not document a fault or a troubleshooting result.
- A 100 Mbps rating alone does not prove that a hub will match every attached interface.
- A hub does not assign IP addresses or correct an addressing conflict.
- Power-cycling equipment cannot repair a wrong cable connection or incompatible link configuration.
Keep the report in perspective: it confirms that a standard 100 Mbps hub operated successfully in one installation, not that all generic hubs are interchangeable.
Match the hub to the DL205 Ethernet interface
Check the model and documentation for the Ethernet interface installed in the DL205 system, then compare its supported Ethernet speeds and duplex modes with the hub and the other connected devices. The question identifies the PLC family but not the interface model, so do not infer its supported modes from the family name alone.
A hub repeats traffic among its ports and shares the Ethernet medium; it is not equivalent to a switch. A hub can be suitable when all attached interfaces can establish a compatible link and the shared-medium behavior is acceptable for the application. A modern switch may be a more practical replacement when a suitable hub is unavailable, but confirm device compatibility rather than treating the hardware as a drop-in change.
Check the physical and network conditions
Before commissioning, inspect the complete path from the PLC Ethernet interface through the hub to each device. Verify that cables are seated in the intended ports, link indicators show an established connection, and the hub has power. Use the interface and hub documentation to check speed and duplex behavior; do not assume that every device negotiates settings in the same way.
Then check IP configuration independently of the link. Confirm that each device has an appropriate address and that devices that need to communicate are on compatible network settings. A working physical link does not prove that the PLC and programming or application device can exchange IP traffic.
| Observation | Check next |
|---|---|
| No link indication | Power, cable seating, port selection, and supported link modes. |
| Link present but devices cannot communicate | IP settings, address conflicts, and whether the devices are configured for the intended network. |
| Intermittent or poor communication | Hub condition, shared traffic, cabling, and link-mode compatibility; compare behavior with a known-good compatible network device. |
Commission the connection in a controlled sequence
- Identify the installed DL205 Ethernet interface and read its supported link modes in its documentation.
- Check the hub's documented speed and duplex capabilities. Use the reported standard 100 Mbps hub only when the interface and all attached devices can establish a compatible link.
- Connect the PLC and one other device first. Check power and link indicators, then verify that their IP settings permit communication.
- Add remaining devices one at a time. After each addition, test the required PLC communication and watch for loss of link or degraded behavior.
- Record the interface model, hub model, link behavior, and network settings that pass testing so a later replacement can be matched to the working arrangement.
Verify the network before returning it to service
Test the communication the machine actually needs, not just the presence of a link light. Confirm that the programming or application device can reach the PLC, that required data updates reliably, and that communication remains stable with the expected connected devices. If the installation fails, isolate the cause by testing the cable path, one device at a time, and the documented link settings instead of changing several variables together.
Do not treat a successful link test as proof that the network is suitable for every traffic load or application. A hub shares the medium, so assess the actual network behavior under normal operation before relying on it for production.
FAQ
Can I use a standard 100 Mbps hub with a DL205?
A standard 100 Mbps hub worked in one reported DL205 installation. Check the exact Ethernet interface and all attached devices for compatible link modes before using one.
Does a hub configure the DL205 IP address?
No. A hub repeats Ethernet traffic; it does not assign or correct IP settings. Configure and verify addressing on the PLC interface and the communicating devices.
Can I replace the hub with a switch?
A switch may be a practical alternative, but confirm compatibility with the DL205 interface and other devices, then test the required communication before returning the network to service.
Stop and contact AutomationDirect through its official support channel if the interface documentation does not resolve link compatibility or communication remains unreliable after checking cabling, link modes, and IP settings. Have the DL205 Ethernet interface model, hub model, and observed link behavior ready.