Author Topic: Ethercat variable latency  (Read 1195 times)

hypnotize

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Ethercat variable latency
« on: November 13, 2018, 09:11:12 AM »
Hi
I am using the AdvancedHMI C# project. Just started a new project, added an ethercat adapter, and i can see the variable in the PLC. The problem is there is a 10 second delay from the real value of the variable, until I see it on the HMI.
I use port 851, there is just a regular cable between the PLC and the PC.

What could be the issue of this latency/ delay?

Thanks

Archie

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Re: Ethercat variable latency
« Reply #1 on: November 13, 2018, 09:27:07 AM »
Do you have TwinCAT installed on the same PC that you are running the HMI? If so, either uninstall it or Stop the TwinCAT system. The AMS router interferes with the AdvancedHMI TwinCAT driver.

hypnotize

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Re: Ethercat variable latency
« Reply #2 on: November 13, 2018, 05:30:09 PM »
Hi
I use the same PC to program the PLC with Twincat  3 and it also runs the HMI. How can I program both and run and debug the advancedhmi software? I don't want to stop the Twincat all the time...

Archie

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Re: Ethercat variable latency
« Reply #3 on: November 13, 2018, 05:34:02 PM »
Unfortunately it is not possible. There is a bug in the TwinCAT router that has been there for many years that will reroute response packets to a different port other than the one the request came from. Beckhoff would not allow their DLL to be distributed with an open source project nor would they divulge the information on how it worked. So the AdvancedHMI driver is based strictly on the TCP/IP stack and does not use the router which is the cause of this limitation.