I currently use a script in WinCC advanced SP1 to log data from S7-1200 and S7-300 PLC's to a csv.

This works great but I can only log data at a maximum speed of 10 samples per second (100ms between samples). This is a limitation of the settings in wincc. I have also investigated using an OPC server (National instruments) but although you can request a high sample rate, the effective sample rate also seems to be limited to 100ms between samples.

I have played with the idea of logging 1 second's worth of data at high resolution (every 20ms) to a data block in the plc, then transmitting the contents of the data block every second to the HMI for data logging. However, synchronisation of the operation is not easy.

any help would be great

thanks.

any help would be great

thanks.

It is possible to archive data faster than limits of SCADA but by using system functions.THIS is an instance.Those options are NOT available for smaller CPUs as far as I know!

Instructions:
The smallest archiving cycle in WinCC Tag Logging is 500ms. There is no way of reducing this archiving cycle time through settings in WinCC Tag Logging. Shorter archiving cycles can be achieved through process-controlled archiving.

There are the following options for this:

• "AR_SEND" (SFB37)
  In an S7-400 CPU you can implement the "AR_SEND" (SFB37) block for process-controlled archiving in WinCC. With this method the archive data is collected in the controller and then transferred to WinCC as raw data. A conversion DLL on the WinCC side interprets the data sent and enters it in the WinCC archives. You must also interconnect AR_SEND block appropriately in the controller. In WinCC you only have to assign parameters, no programming is required. Information on how to use "AR_SEND" is also available in Entry ID 23629327 and Entry ID 23629424.
• ODK for user-specific processing of raw data
  Also with this method the data is collected in the controller and transferred to WinCC as raw data. The data is processed and archived using a conversion DLL. The "AR_SEND" (SFB37) block is not available for smaller controllers (S7-300). You have to program this function yourself. The WinCC option "WinCC Open Development Kit" (ODK) provides information on how you can process the raw data received in WinCC using your own conversion DLL.