OPC client with Lazarus

[vinceducat]

Hi i want to know if someone developpe an OPC client With Lazarus.

[felipemdc]

What is OPC?

[ahmetnurideniz]

opc is  device programing on com port or lan port may be plc(programing locig control)
i want to develop it. but i don't know enought freepascal and lazarus programing.
if you use simens plc you can test libnodave components. it has delphi and pascal version. may be it can port for lazarus.

[Guzzi]

You will find a OPC Client Tool Kit for Delphi and Lazarus at:
http://www.dopc.kassl.de
It is not free, you have to pay for it.

[avra]

There is a lot of free Delphi OPC server/client code here:
http://www.opcconnect.com/delphi.php

Maybe with latest COM/DCOM advances in Lazarus, conversion would be possible with some manual effort. Anyway if you decide to try it then I suggest using SVN Laz+FPC versions.

[mig-31]

I think it will be better to release server/client for OPC UA. It is multi-platform . Do not need COM/DCOM.
Anyway mostly it better use MODBUS TCP to communicate with PCL and HMI devices. PascalScada project support it.

[avra]

I think it will be better to release server/client for OPC UA. It is multi-platform . Do not need COM/DCOM.

OPC UA specification is not free and available only to members. There isn't any free implementation even for Delphi. The day it shows for either Delphi or Lazarus will make me very happy. Till then, OPC DA is quite fine and working with current OPC servers.

Anyway mostly it better use MODBUS TCP to communicate with PCL and HMI devices. PascalScada project support it.

That is all right if your device is also talking MODBUS. Although MODBUS is one of most widely used protocols there are thousands of others, and if you make your application OPC client instead of just MODBUS client, then you will be able to talk to almost any device (not just ones with MODBUS) since OPC servers exist for virtually all of them.

[jl]

It has been 2 years and lots of new solutions are using OPC UA, just want to check with you guys if there's any endeavor on OPC-UA Client along the likes of the opcdelphi project?  Thanks in advance. 

[avra]

It has been 2 years and lots of new solutions are using OPC UA, just want to check with you guys if there's any endeavor on OPC-UA Client along the likes of the opcdelphi project?

There isn't FPC/LAZ solution yet. The good thing is that that there is now an open source solution in C at http://open62541.org. The bad thing is that no one with free time seams to be interested enough to convert it into Pascal. There is another C solution at http://www.openopcua.org, but unfortunately author allowed using it only as a library from Pascal - which makes it a worse candidate.

[avra]

https://sourceforge.net/projects/myopcclient/?source=directory

OPC components now exist for Lazarus, too. Unfortunately GPL.

[jl]

https://sourceforge.net/projects/myopcclient/?source=directory

OPC components now exist for Lazarus, too. Unfortunately GPL.

It's only OPC DA, still no UA.

[avra]

It's only OPC DA, still no UA.

I am happy anyway, because I will be able to get rid of D7 in few of my old projects. Unfortunately because of GPL I will not be able to use the component, but since OPCDA headers are not under GPL I can use just them. It will save me some time at least.

UPDATE: Just changed server from Kassl to Matrikon which I had on my dev machine and Test1 demo works.

[ZbynekZ]

It is possible to develop OPC client in Lazarus with QuickOPC, http://www.quickopc.com. It is a commercial product. For Windows only. Supports OPC DA, OPC A&E, and OPC Unified Architecture (data, and Alarms&Conditions, currently). Some more info: http://kb.quickopc.com/First_experiences_using_QuickOPC_with_Free_Pascal_(Lazarus) .

Disclaimer: This is a self-promotion.

[Daren453]

Did you have issues with opcconnect on the encoding? If so can you tell me the work-around?

Thanks,
Daren

[LacaK]

I have created pascal wrapper to open source http://open62541.org.
You can look at http://lacak.users.sourceforge.net/ for headers and Windows DLL

There are also implementations of other industrial communication protocols like Modbus TCP or EtherNet/IP