Triggering 'LogTag' function in panel from CPU

Hello

My current project is using 2 encoders to plot a cam profile. I used the RV function of one encoder to trigger the logging of data from both encoders into an array in the CPU. This worked very well with the greatest error being around 3 microns but the array size becomes a big problem.

I have switched to logging the data within the panel in a data log but I can not find any way to trigger the 'LogTag' function from the CPU. I might be having a senior moment but I can't think how to induce any HMI function directly from the CPU.

I need to take logs at very regular intervals based on the position of one encoder. They could possibly be moving at an irregular velocity, possibly even stopping midway through the measuring process so constant logging would not be appropriate.

CPU 1211C AC/DC/Rly

SB 1221 DC 200Khz DI 4x5VDC

HMI KTP400 Comfort

I will need also to display the result in a trend and export as .CSV.

Help would be greatly appreciated.

Thank you

Andy

You can use the trace function in CPU 1200 after firmware version 4. I think it is the best for your scenario.
But the problem might be that you can only have two traces running on the CPU, once a recording is completed, you need to get it with TIAP and restart the trace again manually.

Usab

Hello

I was looking at the on change option rQx but it may be possible some results do not change. Regardless the tag table is restricted to 2048 tags but counts each record of an arrayas 1 tag, I have 10,000!

I suspected that there must be a simple solution and I think Usab just pointed it out. Today I managed to capture the data in an array and then address each result in turn and send it to a trend view. It works but on Monday I will be looking at the trace function.

Thank you Usab.

Andy

Ok so the trace function is not right for this project. Today I have tried capturing the data straight into f(x) Trend view but I was unable to do anything with the data, I need a .csv file and we don't have the package to do that.

Next I tried saving the data into the HMI data log in historical data. Great I can create a csv file and view it in trend but my csv file only has one entry. It appears to be overwriting the same entry. Also I don't appear to havecontrol over when the data is captured,it logs every 100ms.

I have started looking into a VB script to do what I need but I know less about VB than I do about Siemens!

Learning all the time....

So I managed to create a small VBA script by modifying an example I found and it works by writing the readings from 2 encoders straight into a csv file. Unfortunately it is too slow and once it has missed the trigger point it falls over.

There must be an easy solution to this but I can't find it with my limited knowledge of Siemens.

If you need the .csv file, trace is able to do it.

First you need to save the record and then you can export it as .csv

Usab

Usab

Thank you for your persistence. The trace function works very well but is reliant on having TIA Portal connected and running. Do you know if this can all be done in the HMI? It would be perfect if it can.

Andy

I have gone back to capturing in an array and now using VB script to transfer into CSV.

Almost working but does anybody know why when addressing the array 'SmartTags("scanData_capture{0,0}") works but if I use 'SmartTags("scanData_capture{counter,0}") it does not.

Very new to Visual Basic so even the basics are not obvious.

Thank you

Just found help that says the correct syntax is

SmartTags("scanData_capture")(count,0)

This still does not work. It says that scanData_capture is not a valid tag.