S5 948U CPU with IM308-C to WinCC Flex RT App

I have a rather unusual and confusing app in which I need to develop a PC Based HMI in WinCC Flexible to communicate with an S5 155 (948U CPU) via Profibus using an IM 308-C Profibus interface module in the PLC rack and a CP 5611 in the PC. The PLC also has an Interbus Controller and a CP 1430TF ethernet card in it for other functions.

Looking into the WinCC Flexible documentation is appears my four options for HMI development related to I/O area that can be transmitted and received are: tiny, small, middle, big. With "Big" having a limit of 128 Input Bytes and 64 Output Bytes.

I need more tags than this limitation allows. If I have more than this amount of data. Is this a maximum amount of data that can be transmitted per transmission? If I have more tags than this, will it still work and have to make multiple transmissions to exchange the full amount of data? Or will I have to use an OPC server to exchange a larger volume of data?

If anyone has experience with this sort of application, I would greatly appreciate the advice. I have managed to set-up an OPC server following an example from the Siemens Support Site, but I'm not really clear on the procedure to declare tags in the Simatic Net.DP OPC server and manipulate them via the OPC server. The Siemens documentation on the OPC server is not very clear at all, but I'm brand new to the OPC server world, so my ignorance may be a contributing factor also.

Thanks in advance.
Chris

CT782 said:

Looking into the WinCC Flexible documentation is appears my four options for HMI development related to I/O area that can be transmitted and received are: tiny, small, middle, big. With "Big" having a limit of 128 Input Bytes and 64 Output Bytes.

Click to expand...

Chris,

Is that right? I thought WinCC Flex went up to at least 2048 tags, whether the tags are declared as bits or double words, as I don't use WinCC Flex I can't confirm this.

We use WinCC with our S5 PLC's, the same processors as you are using as well, I believe, but we don't interface via an IM308C, we use a CP5431 FMS card, I don't think an IM308C can do what you want.

I have never set up a CP5431 from scratch, just modified and added tags, although I have set up a PC from scratch. I might be able to be some help though.

Paul

I am guessing here, I have never worked with an IM308C before.
The limitation must be in the IM308C. I think that you have setup the PC with CP5611 as a DP slave. If that is so, then every tag is an I/O address in the S5 PLCs, Win CC Flex cannot access the memory in the S5 PC directly, so it is limited to the max amount of I/O data.

You may be able to do something with tag multiplexing. With this I mean that you have to program the multiplexing in the PLC. Do not use the tag multiplexing in Win CC Flexible because this does not save any of the precious I/O data area.

If this is not enough for you, then you should consider to invest in some more comms hardware. Maybe an FMS capable card in the PLC like Paul mentions.
If Siemens dont have these anymore (their S5 support is evaporating rapidly these days) then try to contact INAT.

Paul/Jesper,

Thanks for the advice. After a lengthy discussion with Siemens tech support, I learned that, due to the fact the S5 has to address the HMI as a Master or Slave device with the slave being considered a 'virtual remote I/O station', I am limited to 244 bytes with an OPC server or 128 communicating direct.

Two days ago I discovered the INAT site. I discussed the application today with the U.S. contact for INAT. We are going to proceed with the INAT S5-TCP/IP CP and their OPC server as well. I've read most of the documentation on these products, and I believe it will do exactly what we need to do with less program modification than would be required with the PROFIBUS option.

I am confused somewhat on the 'Page Handling' by the SEND/RECIEVE functions in the S5. I understand you specify the base SSNR and offset for your SEND/REC function, but how does the data get into these 'pages'? Or am I way off base with how this works?

Thanks,

Hi CTC82.

Are you sure that you have to use send/recieve interface ?
Cant you poll from win CC Flexible directly via TCP/IP ?
It is 12-13 years ago that I worked a little with ethernet to an S5-135U, and I can remember nothing about it.