OPC server for modbus RTU

apetkov5 · Jan 25, 2013

Dear all,

I nead OPC server that will be able to connect several modbus rtu devices (slaves) trough RS-232 and collect datas from it.

First device is connected to COM 1
Second device is connected to COM 2
Third.....

After that I will connect SCADA to this OPC and get collected data....

I have tried Matrikon OPC for modbus, but when downloaded i can not start installation ? so I nead some other OPC to install it...

What is best OPC server for mine situation ?

Best regards!

Mark- · Jan 25, 2013

Hello,

We have one that might work for you.

apetkov5 · Jan 26, 2013

Hi,

can you sugest me what to use and where to find it

Best regards!

Mark- · Jan 26, 2013

Hello,

> can you sugest me what to use and where to find it

Yes, go to the website linked under my name, and look for MODOPC.

diat150 · Jan 26, 2013

apetkov5 said:
Dear all,

I nead OPC server that will be able to connect several modbus rtu devices (slaves) trough RS-232 and collect datas from it.

First device is connected to COM 1
Second device is connected to COM 2
Third.....

After that I will connect SCADA to this OPC and get collected data....

I have tried Matrikon OPC for modbus, but when downloaded i can not start installation ? so I nead some other OPC to install it...

What is best OPC server for mine situation ?

Best regards!

what scada system? most have some sort of serial modbus driver included.

ramzy2277 · Jan 27, 2013

thanks mark,

also i got a question since this is my first OPC interface to make, but i already made the IO list for the DCS now my question how these tags will be refelected on SCADA, do i have to make similar IO list on SCADA, or the OPC interface will take care of that....plz i need ur advise urgently....

Mark- · Jan 27, 2013

Hello,

It depends on how the OPC server is implemented. The OPC specification does not cover tagnames.

Generally an item in an OPC server has a tagname and an item ID. The item ID is the ‘source’ address in the device the server is reading/writing. The tagname and item ID can be the same.

The OPC client connects to the server via the tagname.

Again, it depends on how the OPC sever is implemented.

apetkov5 · Jan 27, 2013

diat150 said:
what scada system? most have some sort of serial modbus driver included.

"scada" system is wincc flexible 2008 sp2.
It has modbus driver included, but i can configure just one connection. I can connect it to device connected to COM 1 on computer, but i can not connect it to another device that is connected to COM 2 on same computer...

Mark Buskell · Jan 27, 2013

Check out automatedsolutions.com. I have been using their products for a number of years now.

diat150 · Jan 27, 2013

apetkov5 said:
"scada" system is wincc flexible 2008 sp2.
It has modbus driver included, but i can configure just one connection. I can connect it to device connected to COM 1 on computer, but i can not connect it to another device that is connected to COM 2 on same computer...

have you thought about buying a port server like a digi or lantronix? it would be cheaper to buy one or 2 of those and then use the included modbus tcp driver in the software package. Most people are going away from using serial ports on a pc for scada.

Mark- · Jan 27, 2013

Hello,

>... it would be cheaper to buy one or 2 of those...

Cheaper than $29.00 for a MODBUS OPC DA server?

apetkov5 · Jan 27, 2013

Mark- said:
Hello,

>... it would be cheaper to buy one or 2 of those...

Cheaper than $29.00 for a MODBUS OPC DA server?

if it works my accountant will be very very happy

apetkov5 · Jan 27, 2013

diat150 said:
have you thought about buying a port server like a digi or lantronix? it would be cheaper to buy one or 2 of those and then use the included modbus tcp driver in the software package. Most people are going away from using serial ports on a pc for scada.

well, it will be not directly connected to "real" serial ports...

modbus device, with rs-232 port, will be connected to transparent gprs modem.

gprs modem will be connected to pc with fixed ip adress.

pc run programm called port redirector, that make virtual com ports...

scada engine will be connected to that virtual com ports. (over the opc)

Mark- · Jan 27, 2013

Hello,

Based on your last description, I assume each device has a unique slave ID.

If so, then in MODOPC, I would set up the ports to use the RS-485 driver. Then it will poll each device in order. The port redirector should not know any difference. Configure it for the one serial port.

Otherwise, in MODOPC if you set up each slave device as using a 232 serial port, MODOPC will attempt to poll all the devices concurrently. And I think that would be trouble, depending on several factors.

apetkov5 · Jan 27, 2013

Mark- said:
Hello,

Based on your last description, I assume each device has a unique slave ID.

If so, then in MODOPC, I would set up the ports to use the RS-485 driver. Then it will poll each device in order. The port redirector should not know any difference. Configure it for the one serial port.

Otherwise, in MODOPC if you set up each slave device as using a 232 serial port, MODOPC will attempt to poll all the devices concurrently. And I think that would be trouble, depending on several factors.

seams logical.... i will try to do it.

so shall i do next:
- configure just one port in comport redirector (serial port is defined only by tcp port)
- each gprs modem to connect to defined ip adress and just one defined port (defined tcp port that replicator put to serial port)
- set each device different modbus slave adress (device one: 1, device two: 2,....)

or you mean something else?

OPC server for modbus RTU

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