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Author Topic: Communication across subnets  (Read 7703 times)

LukeWhite

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Communication across subnets
« on: March 21, 2012, 09:22:57 AM »
I'm afraid I already know the answer to this, but is there any kind of workaround to enable NetEdit3 (and ultimately DSData Server) to communicate with ECOM100 modules across subnets? 

My situation is this, I have purchased two pre-packaged machine downtime monitors built on Automation Direct PLC's.  They communicate back to an Excel spreadsheet used for setup and data logging.  The link to Excel is set up through DSData Server.  I currently have one monitor in a building with a 10.1.131.--- address, and one in another building with a 10.1.141.--- address.  My computer that is intended to monitor these systems is in the 10.1.131 building and can't see the system in the 10.1.141 building.  I can ping the ECOM module and I can access the modules web page from that computer, but I can't figure out a way to see it from within NetEdit or DSData Server.  I had to connect to the module directly with a crossover Ethernet cable in order to set the IP address.

In hindsight, this may be a question for the DSData Server forum, but I have a feeling that if I can't see it from within NetEdit, I won't be able to see it from within DSData Server.  If this needs to be moved, moderators please do so, or I can re-post in that forum.

Hopefully there is a solution for this.  We are considering standardizing on this brand of downtime monitor for our plant, but if it can't communicate across subnets back to a central computer, then it is of limited use to us.  Had I known of this limitation in advance, I probably would not have purchased this system. 

MikeS

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Re: Communication across subnets
« Reply #1 on: March 21, 2012, 03:02:16 PM »
the crux of the problem is that NetEdit uses broadcasts to populate the list of devices, but switches, routers, and similar network devices do not allow broadcast packets to pass through. that's why you cant see the ecoms on the far subnet with NetEdit.

the dsdata server's link wizard uses a similar approach to find ecoms that you can build a link to, BUT, since you can ping the ecoms on the far subnet you can manually construct a link in the link editor (not the wizard), so you should be able to get dsdata to work.

you used NetEdit to give the ecom that will live on the far subnet an IP address with the cross-over cable, right? what do you need NetEdit to do now that the IP address is set ?
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franji1

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Re: Communication across subnets
« Reply #2 on: March 21, 2012, 05:37:19 PM »
NetEdit is a configuration tool - it works in a mode where you will be on the same physical subnet to do the configuration.  It is not able to find an ECOM with an ip address of 255.255.255.255 across subnets.

Most of the other "runtime" (like the CommServer of DSData) can utilize TCP/IP addressing once it's configured.  But even the CommServer of DSData has that "configuration mode" when you are FIRST setting up the comm link (similar to NetEdit).  Hence, it must ALSO be on the same physical subnet to use the LINK WIZARD.  HOWEVER, as Mike said, if you already know the IP Address (i.e. it's already configured), SKIP the wizard and hard-code the link parms via the normal Link Editor dialog/tabs.  You may need to tweak the timeouts and/or retries if you are dealing with multiple layered subnets where the IP bandwidth can get a little "heavy".

LukeWhite

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Re: Communication across subnets
« Reply #3 on: March 22, 2012, 07:43:52 AM »
Thank you guys for the help! 

I was able to get it working late yesterday afternoon.  The point about manually setting up the link in DSData Server was the key. 

MikeS

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Re: Communication across subnets
« Reply #4 on: March 22, 2012, 08:29:43 AM »
excellent
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RhodneyTodd

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Re: Communication across subnets
« Reply #5 on: January 21, 2013, 02:14:55 AM »
Yeah, the manual setup also worked for me just fine. Thanks guys for solving my problem also.  ;D
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