how can I connect LabView with a PLC S7-300?

[Nura]

Hi Folks
I want to build industrial equipments like tanks/heaters/valves/motor or mixer/RTD/Level sensor in LabVIEW
i could find tanks/RTD but i couldnt find the rest.
After building these things i want to control the action of this total process by PLC Siemens S7 200
i dont have any idea about this thing
Let me know how it can be controlled whether by using RS 232/ RS 485 or OPC server
if so is OPC server is a software...where can i download or where can i buy
If any body could help me i will be happy

[preston_johnson]

consider

www.ni.com/opc

www.opcfoundation.org

[Nura]

I have S7200 PLC and its OPC server to interface LABVIEW
Should i program anything in LabVIEW
or just build and interface the PLC

[Ryan.S]

First, you can use ServerExplorer to see if the OPC server runs properly with the PLC. It's easy to use and test.

Then, in LabVIEW you can find some examples that show how to use datasocket to connect to OPC server.  

[Nura]

Its all fine and thanks for your reply Ryan

but i just want to know should i connect the stuffs in Block diagram of labview

and i couldnt find any exampleds like that

i wil have opc server in a day

i have built tanks and pipes in labview but i didnt even connect the block diagram

i just want to open and close the valves if the level reaches certain and so as the temperature

how to compile this project..

i have no clue regarding this stuff..

so only i am disturbing you like this guys

thanks and will be happy if you (anyone) reply in detail

thanks again

[Ryan.S]

In LabVIEW "Find Examples", search "opc", you will get several examples that show how to use datasocket to connect opc server.

The only thing you need to care is the URL. The format is like this: opc:/ServerMachineName/OPCServerName/ItemName. Those examples show in detail how to construct the URL.

[Nura]

yes ryan i could see examples about OPC but i dont have any clue on that stuff

i have the OPC PC access for s7 200 right now

but i dont know how to start ...i dont have any knowledge on this

i just want to do this project and leave off. so  let me know what should i do to control the flow of tanks simulated in labview by PLC

pleaseeeeeeeee...........reply me as soon as possible

many thanks

[Ryan.S]

The example "NI Demo OPC Client.vi" clearly describes how to do it.

You can use a probe to get the URL connected to Datasocket open.vi. It's "opc:/National Instruments.OPCDemo/sine:0.0..8.0:3.0?updaterate=100". 

National Instruments.OPCDemo is a demo opc server running on your machine. "sine:0.0..8.0:3.0" is a simulated item. You can ignore "?updaterate=100" 

So, use your opc server name and the item name here, which can be found in the ServerExplorer.

Which part can't you understand in this example?

[Nura]

yes i have programmed plc

when i access the program in PC access the value is bad

the same is when i test with the server explorer also

but the program is running properly  with external inputs

what can i do ryan

my program and my pca file for ur verification

[Justin_M]

Hi Nura,

Are you still using the OPC server?  Is it up and running?  I would first make sure that the OPC server is working correctly, and then go from there.  I know you said you haven't really used an OPC server before, but there is lots of information online that should help you through it.  Take a look at the following link for a starting point:

Connecting LabVIEW to an OPC Server through a DataSocket Connection

Thanks,

Justin M.
National Instruments