Problem with disappearing graphs in the module "X/Y Chart"

[Slawek_PL]

I have a problem witch module "X/Y Chart", because sporadically and only sometimes, after starting the program, the chart is cleaned while the program is running but before it's ending.
In addition, the chart cleaning in different runnings does not at the same time from the start.

In the attachments below two examples of what it looks like.

I am asking for any tips and suggestions, thanks very much.

 

[jrys257]

Hello,

There is a setting on x/y chart called Delete After. It clears the graph buffer at x number of data blocks. Set it to the maximum value and it should help. 

Best regards,
John

[Slawek_PL]

Hello,

thank you for the tip. Currently i have set 9600 blocks, I will try set higher value, but I have no idea how this value is determined / calculated? I will be grateful for any tips

[hw70]

Data transported from module outputs to module inputs is organized in blocks. A block of data can hold 1 to 1024² values (samples) since DASYLab 14/2016 (DASYLab 13 and older: 32768).

The XY chart clears the display after X blocks that were received on the inputs.

If the data source (the module that has outputs only) outputs data with (e.g.) 10 Hz and BS (block size) 1, you get each 0.1s one data block that holds one value.

If the XY chart is set to clean-up the display after 100 blocks, you can see the data of the last 10s -- 10 blocks per second (10Hz BS1), 100/10 = 10[s].

If the data source outputs data at 1000Hz and BS 1000, clean-up still after 100 blocks, you can see the data of the last 100s: 1000Hz BS 1000 --> 1 block/second. Clean-up after 100 blocks makes 100s time to observe the graph being painted.

You can use the module Data window to create "some big blocks" from "lots of small blocks"

You can place a Relay module in front of the XY chart to block any data being send to the XY chart -- that will make the XY chart "hold / freeze" the data displayed, because if no more data is added to the XY chart, the block count to clean-up the display cannot be reached.
Obviously, data that was blocked by the Relay is not added to the display, if the Relay lets data pass again.

[Slawek_PL]

Thank you very much for your thorough answer - it was very helpful and allowed me to solve the problem. Since the introduction of the changes, the charts have never been deleted, and over a dozen of them are generated daily (tests of the friction coefficient of friction materials)