Hi

I am setting up a WinCC professional V16 system that will read input data on Modbus from a bespoke device. It is likely that this device is compliant with the original Modicon specification.

Now, WinCC provides a driver for Modbus with only very few options for setup. It offers very little to customize the reply if I run into any issues. I have plenty of experience of Modbus from many years in the oil industry and am well aware of some of the peculiarities of some implementations. 

I spent some time searching around and discovered that Siemens offer a CSP (Communication Service Package) that provides a Modbus driver for WinCC. I had hoped this might provide a more configurable option but found the documentation somewhat lacking and am not sure if this can even be used by WinCC Professional. 

Having installed the driver into Tia Portal I can see no additional configuration to allow me to use it. I can see no difference in the configuration options that are available. In the Connection I still have the  same options for the Communications Driver (currently Modicon Modbus TCP/IP). 

I am thinking that maybe this has only added the driver for WinCC Advanced etc. as Professional already has a driver. 

My worry is that I may well face Endian issues as this is quite a common problem. Admittedly I can probably code around this but that is not my favored route.

Hello Brian;

The CSPs available for WinCC (TIA Portal) are not strictly speaking an upgrade of standard communication drivers, but extensions and tests of existing communication channels to include different controllers that were not covered in the original version of the driver.

https://support.industry.siemens.com/cs/ww/en/view/109739698

There are no additional mechanisms to deal with issues in the driver n the CSPs,, such as handling of endian problems, which can be frustrating. Most PLCs give a programmer the capacity of dealing with such issues, and that could be an alternative to using WinCC directly with your transmitter; collect the data inside the PLC with all required corrections and formatting, send the data to the WinCC Professional screens when it is ready.

This is generally the way we preferred handling such situations.

Hope this helps,

Daniel Chartier

Hmm. As I suspected. WinCC is not really the right tool for this job. I did not mention a PLC because there is not one, this is an embedded device that has a Modbus interface and I just need to collect some data.

I can easily use a little C Script to sort out the endian issue but it is not a pretty solution. Most mature Modbus drivers offer configuration options to deal with the common issues but it is an ageing protocol that is not mainstream anymore.  

Brian W

Just a quick not to end this. The WinCC Modbus driver did work but returned values that were endian swapped. A simple C Script was used to correct this. 

 Hi, can you share more details on your solution?