HMI trend view but not cyclical, using a trigger

Hi,

I  want to have a trigger bit to store a measurement result and show it on a graph. Lets say 100 of the most recent values will be shown. I can store the 100 values in an Array and would like to just create a graph from that. Seems impossible with the built in tools.

Trend view seems like the right tool for the job... or is it?
It seems like it is meant for cyclical data logging. I cannot add a new value by pressing a button.
There is this "Trend type" "Bit-triggered real-time" but this involves some weird communication of requesting trends and looking at specific bits - so not what the name suggests and not useable.

The f(x) trend view also expects cyclical data and does not accept arrays.

There was an application example:
Creating an f(x) Trend View for Comfort Panels and WinCC Runtime Advanced
https://support.industry.siemens.com/cs/ww/en/view/109481693

My requirement seems simple enough - display the recent measurement history.
For example the length of a part that was measured by a probe. How can I do it?

Hi AutoGen_6815244,

I'm afraid that if you are using WinCC Advanced and you want to show in a graph for example the last 100 values of a variable it will not be possible. Keep in mind that WinCC Advanced is still the HMI like a panel but on a PC, so it has more limitations than WinCC for SCADA (WinCC Professional) where you can dynamize absolutely everything in the curve viewer and therefore you could implement what you are looking for.

What it does allow you to do is to show the history of all the variables stored in the curve viewer, but not individually and by a specific number.

Hi,

I was able to log data... unfortunately displaying the graph is not great.

- Although I selected the trend style to be "Points" it is displayed as a line. When I zoom in, only then I can see individual dots.

- The graph does not refresh itself when new values are added. I have to go away from the screen and then back again to see a change. Not great for monitoring a process.

- It seems to log a lot of points ... even when I have only logged once. I am not sure what is happening. I dont know if selecting the "time axis" to be visible makes this difference. More points are displayed when time goes by... even without actually logging any new points.


I don't know if some VBA scripts or something is able to display measurement results on a graph as they are measured and the graph is updating.

Now I have been messing around with the TrendControl VBA script that Siemens has created and documented and I have very mild progress. Link in the first post.

It is meant to take an Array of X axis values, and an Array of Y axis values from the PLC, send them to the HMI and VBA script inside the HMI converts the values into a compatible CSV file that you can show on a Trend f(x) chart. This CSV file is placed on a SD card inside the HMI.

I am able to get the data from my arrays into the CSV file and sometimes even display the points on the chart. But updating it is not happening.

First of all the scripts are different in the Siemens provided PDF and in the Siemens provided sample program.

Why must it be so complicated and frustrating?

The only thing that seems to update the chart is:
- Power off and Power on for the HMI
- Go to a page where the Trend f(x) is .... its blank.
- Press the "Update Trend" button that runs the VBA script... still nothing happens but system messages indicate that something is happening.
- Go away from the page... Come back to the page.... and voila... chart is updated.

EDIT: I got it to work somewhat by removing the sections.

If Err.Number <> Then Exit function

So if an error occurs when deleting old file, creating new file, writing to new file... the function is cancelled... perhaps too soon.

Another part in the VBA code that was perhaps problematic was 

OpenAllLogs
Do While SmartTags("LogsAreClosed") = True 'Wait until all logs are opened

Loop

 It works by mapping a system event nr "80019 - All logs have been closed successfully" to a HMI tag "LogsAreClosed"
The system event has an "Incoming" event under which I can create a "SetBit" behavior.

So if the script loops when LogsAreClosed ... it will only stop looping when the logs are NOT Closed... meaning they are opened.

There is no opposite system event... so no "logs are opened" and using the "LogsAreClosed" in this inverted way might not actually work.
If the LogsAreClosed bit remains Set and nothing resets it, this loop goes on forever.

So I removed this part and it works.
Also ... the button that runs the VBA code is also doing an "Activate screen" event... activating the same screen it is on refreshes the screen and loads the new data.

So nothing updates automatically, you still have to press a button, it takes some time to close the logs, delete the old file, write a new file with new values, open the logs again and refresh the page. Pretty bad for an HMI that costs that much to have no basic functionality to display measurement values.