RS232/RS485 to OPC Server experience?

Hello World!!

I look for experience of engineers using RS232/485 to OPC server converters. I'm interested to know what you used/tried and your experience in stability and ease in configuration.

In my situation I will maybe use it to transfer tag data to a process data historian.


Cheers,

Jeroen Groeneveld
Arnhem, Netherlands

RS232 and RS485 are electrical definitions of serial data connections.
ALlmost all data communications is done serially, and a large part is by RS232 or RS485.

An OPC Server is a piece of software that acts as an interface to a data communication protocol. It can be ANY kind of protocol, there just have to be a OPC server for it.

You need to specify a little bit more about what hardware and/or which point-to-point protocol or bus standard you are interested in. (examples: Modbus, Profibus, Devicenet, Ethernet/IP etc. etc.).

Hello Jesper,

Thanks for your reply.

The situation is this:
I want to collect data from a device (Enraf) and send this data to a process data historian (OsiSoft PI). Since the distance between the Enraf device and the process data historian is to much to use a serial line (modbus) I consider to convert this modbus signal to OPC. With a remote OPC connection I can easily extract this data with the excisting netnode and transfer it to the process data historian. (The advantage is we don't have to buy a new interface since we can use the excisting one)

I hope you don't look now.

Regards,
Jeroen

Hello Jeroen;
So, basically, you seem to be looking for a Modbus(serial) OPC server package. There are many products that can be found in the market. from Matricon, Parijat, Kepware, and probably many others. Look it up on Google.
However, when you say server, you also require a client to establish communication. A server makes data available; a client requests specific data from the server's "menu" (think of it as ordering in a restaurant: a client selects specific info from the server's menu).

So, on the computer you choose to install your OPC server to collect data over your Modbus link, you will need to install the OPC client (presumably a software bundle from PI), organize the data exchange between server and client, and then transfer the collected data to your application (you did not mention specifics, but it seems natural to assume TCP/IP).

For further info, you will need to give us more specific details on your project.

Hope this helps,
Daniel Chartier

Thanks Daniel,


That's right, I'm looking for a Modbus(serial) OPC server package.
I already found more then a few prodect excist so that's why I came up with the question "does anybody has RS232/RS485 to OPC Server experience?"

Let me paint the picture for you a bit more detailed:

Enraf/Modbus (A) -> PC with OPC Server (B) -> Netnode PI with OPC interface (C) -> PI Server (D)

A & B are located in one physical room. C is located near some DCS systems using already OPC data collection. D is located somewhere in a server room.

So device A sends data by RS232/Modbus to PC B where the data is made available in the OPC server. The OPC client is installed at PI Netnode C somewhere on the TCP/IP network (a remote OPC connection will be established using OPCENUM). This netnode C sends the collected data to the PI server D.

So basicly I like to know if someone has good/positive experience with a Modbus(serial) OPC server package.


Jeroen Groeneveld

Serial OPC is slow

We tried OPC once. OPC was too slow. We removed the OPC server wrote the client to access the machinery using only the serial protocol and were happy.

Hello Peter,

Thank you for your input! I'm interested in your specific situation: > Can you tell me how many tags you tried to get over the OPC server you used.
> Can you tell me something about the manufacturer or name of the package you used?
> What was the Serial connection speed you used?


Regards,
Jeroen Groeneveld

Modbus OPC server

Jeroen,

Try these people, I use their ABTCP activeX controls.

http://www.automatedsolutions.com/products/opcmodbus.asp

Lantronix Xpress DR

I would suggest using the Lantronix DR-IAP. This device is a ethernet to serial converter. There is a driver for this device to convert ther ethernet signals to modbus compatible signals at the device end. Than you just use the included software. Their tech support is excellent and they have an free online live support option that helped me find some easily overlooked problems quickly.

www.lantronix.com

Jeroen Groeneveld said:

Since the distance between the Enraf device and the process data historian is to much to use a serial line (modbus) I consider to convert this modbus signal to OPC.

Click to expand...

Jeroen,

It seems that you have two tasks to solve:

1. To connect to the Enraf device in order to bring the data OsiSoft data collector. Because OsiSoft is an OPC client, you want to use an OPC server to make the connection. Thats OK.

2. Because the distance is too long for RS232, you want to go to RS485. You can do this with two RS232/RS485 serial converters. To change the electrical level from RS232 to RS485 has nothing to do with OPC.
Enraf/Modbus (A) -> RS232/RS485 converter -> RS485 cable -> RS485/RS232 converter -> PC with OPC server and OsiSoft (D)

You can also use your approach of making a combination of a local OPC server connection that brings the data onto the company network.

Hello Jesper,

Maybe I created some confusion about the RS232 and RS485.
My intention is to use only the the RS232 since the pc with the OPC server will be near the Enraf closet anyway (max. 5 m distance).

There was a moment in a project where we had multiple rs232 signals we could combine to one rs485.

beerchug