# HMI Networking

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Thread Starter

#### Sivasekar

I need to send data from a VAX/VMS based HMI system to a NT based HMI(Cimplicity). Both systems will be running simulatneously and controlling separate sections of the plant. Only some 100 tag data to be sent from VMS to NT based HMI. Both are connected by ethernet.

Any Hardware or software solution?

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#### Arvind Sharma

An immediate solution that occurs to me would be to collect data from your VMX system and convert it to a neutral file format i.e a basic ASCII flat file text data file. You could install a message delivering system such as Email or Peer to Peer file sharing system that takes the data once every few minutes or seconds (depending on the granularity you seek) and transfers it to the NT system. A script on the NT invokes the NT OLE or DDE and transfers the flat file data into your NT SCADA/HMI.
Another method would be to find out a protocol that establishes communication between VMX and NT file system ( Pathworks rings a bell in this scenario but I could be wrong).
You could transfer batch data directly and avoid any messaging service.
When your solution requires sending across data in this manner, then I would seriously recommend rethinking the architecture of the process control system. You might work out a way to send across data on a disparate network such as yours, only to end up complicating the scenario wherein troubleshooting/debugging would turn out to be a nightmare for future engineering efforts. I have been a culprit and a victim of such scenarios.

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#### Mike

There's a program called BASEstar which runs on the VAX. It can run as a DDE server and I think OPC server as well, so it can handle communications between the two HMIs. You also might need something called Wonderware Extensions to allow Cimplicity to talk to BASEstar.

Mike

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#### Arvind Sharma

An immediate solution that occurs to me would be to collect data from your VMX system and convert it to a neutral file format i.e a basic ASCII flat file text data file. You could install a message delivering system such as Email or Peer to Peer file sharing system that takes the data once every few minutes or seconds (depending on the granularity you seek) and transfers it to the NT system. A script on the NT invokes the NT OLE or DDE and transfers the flat file data into your NT SCADA/HMI. Another method would be to find out a protocol that establishes communication between VMX and NT file system ( Pathworks rings a bell in this scenario but I could be wrong). You could transfer batch data directly and avoid any messaging service. When your solution requires sending across data in this manner, then I would seriously recommend rethinking the architecture of the process control system. You might work out a way to send across data on a disparate network such as yours, only to end up complicating the scenario wherein troubleshooting/debugging would turn out to be a nightmare for future engineering efforts. I have been a culprit and a victim of such scenarios.

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#### James Wilk

I've had to do the same thing about 2 years ago (but from the HMI to the Vax system.) The best and cheapest way, maybe, is to have the Vax system create a text file (containing the data you need) and ftp it over to your node periodically. Create a template of how the data will be saved (comma delimited?). Script the Cimplicity HMI to read the data and import it into any tags / functions, etc within your HMI. I am not an expert on Cimplicity so I cant tell you what functions will import text data or what the best method.

I did this project about 2 years ago and it is still working and it was pretty cheap to do (didnt have to buy any software / hardware) and it didnt take too long.

Good Luck,

[email protected]

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#### Chriscimhmi

Contact Paul Mentz [email protected] at Neddam Software Technolgies 518-782-9164
http://www.neddam.com/, they have deep experience in interfacing the CIM HMI & VAX worlds and may already have the solution canned for you. Great people, awesome support & hmi/db/comm/api talents there.

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#### Pete Sage

There are a couple of methods that may work.

If your VAX system can act as a Modbus Slave - then you could use CIMPLICITY Modbus Ethernet or Modbus RTU communications module to poll the data periodically. Converesely if the VAX only has Modbus Master capability CIMPLICITY 5.0 has both a Modbus Ethernet and Modbus RTU slave (essentially you map Modbus Address to HMI Points in a configuration file) and this would be a good mechanism to move data to CIMPLICITY from the VAX.

I wouldn't recommend using DDE as a network transport as it isn't one of the more reliable ways to move data around.

I would guess that if the VAX had an OPC Server you wouldn't be asking these questions.

If none of the out-of-the-box solutions work there's a variety of things you can try with scripting. You could have the VAX periodically FTP a file over to the HMI. Then have a periodic event in the Event Editor to run a script to read the file and put the value into CIMPLICITY points. If your file was simply Tag,Value (and you don't have to worry about special characters in strings, etc) a simple script would be like:

Sub Main()
open "d:\data.csv" for input as #1
on error goto exiter
top:
input #1, p$, v$
PointSet p$,v$
goto top
exiter:
close #1
End Sub

The real world implementation is a little more complicated because you need to worry about the file not being completely transferred when you try to open it, etc. I can imagine a number of schemes to do this, like ftping two files (where the presence of the second indicates the first has been transferred)

Let me know if you need more help.

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#### S.Sivasekar

Pete,
Thanks for your good reply. I found out that my customer is using old Cimplicity HMI based on VMS.

I searched around for a OPC and couldn't identify one. Since both sides are Cimplicity is there any common protocol like Point Bridge can be used.

Thanks

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