CANbus - PC - HMI connection

I'm having a problem getting a clear answer to what should be a rather simple question!

Basically I have a CANbus network, and I need to connect it to a PC running HMI software (Citect or Wonderware for example).

Now Ive identified some PCI canbus cards (softing), and I can even find PC based HMIs ready fitted with CANbus cards (advantech), but, when I talk to the HMI software suppliers of the HMI hardware suppliers neither can give me a clear answer if they have available drivers for the other!

OPC would appear to be the clear answer, yes most HMI software packages support OPC, but I cant get a clear answer if the PCI cards support it.

Truth is I've had limited experience with OPC, I understand that the concept is you run a server which communicates with the field devices and the HMI software is a client... but does the server need a driver for the PCI card?, is this server software something free or do I need to buy that as well?, should the PCI card manufacturers be providing the server?

The PLC itself comes with an OPC server however I cant see how this will help I imagine the server is designed to work via the PLCs USB or Serial port, so it may be of use for desktop development but not for the field.

As far as PCI cards are concerned Softing looks to be the leading player, but the local supplier just wants to tell us how they have done great projects in the past using this hardware and isn't actually answering the question!

In simple terms what I need is a list of the hardware and software components I need to turn a CANbus network into something readable by the HMI software... preferably without paying through the nose for it!

The HMI will be an OPC Client, not an OPC Server - except for when the HMI provides its tags to another HMI Client buy itself being an OPC Server. The last ting is a bit unusual so you can ignore it.

The OPC Server must be supplied by the same vendor that sells the PCI card for CAN bus.
It seems that Softing do not prive an OPC server for its CAN PCI card. So you must find anothr vendor.
It looks like this vendor has both the hardware and software you need:
http://www.peak-system.com/PCAN-PCI.207.0.html?&L=1
http://www.peak-system.com/CAN-OPC-server.260.0.html?&L=1
There may be other vendors, this was just the first one I found by googling for "CAN OPC server".

Now you got me confused.

bgkdavis said:

The PLC itself comes with an OPC server

Click to expand...

Is the PLC reading writing the CAN devices, or is the PC HMI reading and writing the CAN devices, or what ?
You cant have two devices controlling the same thing.

What PLC is it ?
What communication interfaces does it have ?

If what you need to do, is to see the i/o that is controlled by the PLC, then you need an OPC server for the PLC, not the CAN bus.

I cant see how the OPC server software for the PLC helps, and I've not bothered wasting time looking at it, its probably intended for USB or serial connection use, its not as if the PLC comes with a CANbus card, and its not as if a OPC server specifically for the PLC helps me talk to the other CAN devices on the network.

Surely the make/model of the PLC is irrelevant as long as the PLC talks the appropriate Fieldbus language, I didn't mention the EMU or any other active CANbus devices on this network, because at the end of the day what I need is a HMI solution that can talk to CANbus without paying through the nose for it!

Repeat the question:

JesperMP said:

Is the PLC reading writing the CAN devices, or is the PC HMI reading and writing the CAN devices, or what ?

Click to expand...

Yes the PLC is reading writing to CAN devices and the HMI needs to read write to CAN devices including the PLC, some CAN devices will only be addressed by PLC and the PLC only addressed by HMI, but the EMU for example will be addressed by both the PLC and HMI........ At the end of the day its a multi master CAN network!

Surely the complexities of cross communication on the actual network is irrelevant to getting Wonderware to talk to a Canbus network! am I really missing the point here!

CAN bus is in principle multi-master.
But I doubt that you really need/want to connect directly to the i/o, bypassing the controlling PLC. The most typical way to do it is to read status values from the PLC, and then send setpoints and commands to the PLC. The PLC then controls the i/o based on the commands and setpoints.
This is a quite common task, and means you have to coordinate the exchange of data between PLC and HMI with the PLC programmer. And you need an OPC server for the PLC.

If you really want to connect directly to the i/o via CAN from your PC, then look at the links I provided already, or do your own search for CAN PC hardware with OPC Server.

The Peak cards and OPC server solution do indeed appear to fill the gap, and that's pretty much what I was finding hard to get a straight answer on, not all CAN PCI cards supply a OPC server and few HMI package's support PCI CAN Cards

With the Peak cards and the explicit statement that the Fastwel OPC server software supports them I can now see see a clear communication chain, ie

IO - PLC & EMU - CAN - Peak PCI Card - Fastwel OPC server - HMI

If anyone else has any other PCI/OPC or HMI with native PCI driver solutions then Id like to look into these as well.

The actual vagaries of the CAN network topology are an issue for a later date, this project is the first time I've done to a fieldbus implementation on a truck, and your right, normally I would avoid having the HMI directly address the IO, but in this application I have an EMU to deal with plus GPS and a security tracking system all working as active CAN masters (and I cant reprogram these) before I even start adding the payload control system.


Thanks