Ethernet noise reduction strategies

[rmore]

I have an HMI on a peice of equipment that routinely crashes (at least once per day) whenever the Ehternet cable is plugged in. I suspect noise from nearly equipment is corrupting the WinCE based HMI. Are there any strategies for reducing the noise coming into an ethernet port? I breifly looked for filters however was not able to find anything, other than isolators. This is a test site for a product we are releasing soon and I would like to have some potential solutions and advise at hand for customers who may experience issues such as this.

As always, ny advise is much appreciated.

 

[IRstuff]

What category is the cable?

Have you considered an optical interface?

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[itsmoked]

That's fairly interesting since typically the only connection between the two communications locations is something like a 1000 puff capacitor to the chassis.

What kind of machine is the HMI being connected too and what is the separation distance between the two?

How do you know the HMI is crashing?

Have you figured out why the HMI is crashing? Does it crash if you have the HMI completely ignoring any signalling on the Ethernet?

Is the HMI in a conductive enclosure?

Is the HMI mechanically grounded to something?

Where is the power for the HMI originating?


Keith Cress
kcress -

http://www.flaminsystems.com

 

[xnuke]

I had an HMI that was crashing whenever I plugged in the Ethernet cable. The unit just locked up every time, with no ability to respond to input. The problem was a massive amount of broadcast network traffic from some PCs on the same network, and the HMI Ethernet couldn't handle being exposed to it. The PCs weren't supposed to be sending those broadcasts, but they were. My IT department identified the problem using the Wireshark application, then went to those PCs and corrected the issue. Have you looked at the network traffic?

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[itsmoked]

That's what I'm getting at too. I suspect it's a SW issue and not a noise issue but with so little info there's nowhere to start.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[rmore]

First of all, thanks for all the responses so far. Let me clarify my request. I am looking for strategies in helping reduce the effects of marginal ethernet connections to our product (trying to keep the number of phone calls down for future installations), and advice for potential customers who experience problems that go away when the ethernet connection is removed. So far, you have given me great feedback that will defintely make it into our manual. I would have never thought of high network traffic, for instance.

As for my own situation, we installed an ethernet isolator going into the HMI yesterday. Withen a few minutes, we had a situation. I forgot to tell the installer to turn off power to the HMI before doing the install, so it was my immediate hope that connecting to a live panel caused the issue. I rebooted the HMI remotely, and last night it ran all night without an issue. Up until then, with the ethernet installed, it had been crashing every night at around end of the last shift. So far, my hopes are sustained. Time will tell.

I am assuming that the ethernet installation is less than ideal, and, as a test site, it's likely to reflect reality for some of our future customers. With that in mind, I am having them keep the cable routing the same for now so I can test the effects of the isolator, as well as, any other hardware that might positively effect the situation (any ideas). Once we run out of ideas, I will have them reroute the cable.

I hope that clarifies the post a little, and again, thanks for the feedback, and keep it coming.

Now in response to itsmoked's generous query

<<<<<<<<<<<<<<<<<<<
That's fairly interesting since typically the only connection between the two communications locations is something like a 1000 puff capacitor to the chassis.

What kind of machine is the HMI being connected too and what is the separation distance between the two? PLC, located inches away in the same enclosure via a 6 ft serial to din cable

How do you know the HMI is crashing? WINCE error window from the operating system

Have you figured out why the HMI is crashing? Does it crash if you have the HMI completely ignoring any signalling on the Ethernet?Disconnecting cable appears to resolve issue

Is the HMI in a conductive enclosure?No, Nema 4X plastic enclosure

Is the HMI mechanically grounded to something?Only at the 120V input to the HMI/color]

Where is the power for the HMI originating?Local 120V sourced from step-down transformer connected to 460V mains in a seperate eclosure
<<<<<<<<<<<<<<<<<<<<<<

 

[djs]

WINCE error window from the operating system

So it looks like the OS (Win CE) has the issue. It could be an isolation issue. Are you using a shielded Ethernet cable?