Hi, as per the graph screenshot shown by you, it shows the Data Count: 3. This could mean the following:
1. The code typed by you has some errors. -> The code shared by you does not contain any errors
2. The variable name to plot data is wrong. -> You can verify the variable name from the hardware configuration. Please not that this is case sensitive. Once you update the code please re-upload the code.
Let me know if this solves the issue for you.