Hi,
I tried to connect C80 PLC with a network switch. On that time it is not communicating with that network switch(Indication on network switch and PLC is not blinking and connected my laptop to network switch and pinged). When im connecting laptop to network switch, the port indication on network switch and laptop is blinking.
Same cable used to connect between network switch and PLC connected to my laptop from PLC eth port and pinged, its communicating. What is the reason for this?? Can i get a Solution from anyone??
Hi,
please check if you are using a “normal” patch cable and NOT a cross-over cable.
Stephan
The cable should be irrelevant in this case as the C80 does support Auto MDI/MDIX
When connecting a switch or hub to the Ethernet port of the C80 the link should work without any issue.
Have you checked if you use the Ethernet port or did you accidentially use the Powerlink port ?
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i tried same connection with cable i used to transfer program. that time also same.
Connected in ETH Port
The cable you used to transfer the program ? So you already transferred over Ethernet ?
Are you using a managed or unmanaged switch?
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Hi,
does the switch have 2 LEDs, often called “link” and “act” (activity)?
And
- if “yes”, are both LEDs off? Or is the “link” LED on, but “act” doesn’t flash?
- if “no” (only one LED), is this LED off or permanently on (no blinking)?
I’m asking, because normally switch LEDs are indicating 2 different states:
1.) the physical link state on layer 1 (is a ethernet connection detected?)
2.) the layer 2 communication state (if packets are going through the port, a combined LED, or, in case of two LEDs, the “act” LED is blinking)
The physical link state is detected by simple voltage pulses, without layer 2 data transfer (auto negotiation, so the detection of the cable type and the communication speed, is part of this layer 1 procedure).
The activity LED, or the flashing of a combined LED, signals that layer 2 data is transferred (most often, only if data is received by the switch port), so the 2 devices are communicating.
If 1.) fails, most often the cause is some defective cable or interface, or the auto-neg procedure fails for whatever reason (for example because of some fixed speed settings in one or both devices, that don’t match).
If 2.) fails, one reason could be that the switch “want’s to see some incoming data on it’s interface” first, to learn the physical address of the device behind (the MAC address), or some filters / setup inside the switch prohibits the data transmission… in such a case, it can be helpful to “force” some outgoing data from the device to the switch, in our case for example by sending a ping from the PLC to some other device (it’s not neccessary that the ping receiver really exists, but sending a ping from the PLC will end up in a layer 2 packet sent to the switch).
Of course the’re many other possibilities why the layer 2 communication could fail, especially if it’s a managed or a “smart” switch.
Best regards!
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Yes, i already transferred through ETH. When im trying to establish connection through switch only its happening. Can connect directly to PC and communicate with PLC through ETH.
using unmanaged Switch
Im using unmanaged switch, both LEDs are not blinking. While pinging packets Sent:4 and Recieved:3.
Ok, now I’m confused: I understood that the communication with the PLC isn’t possible at all, but you’re receiving ping responses?
Are more devices connected to the switch then the PLC and the notebook, is there maybe a IP address conflict (another device uses the same IP address as the PLC)?