I am working on raspberry pi 3. I am using node-red-contrib-modbus and Mysql for my project. I read my data from Modbus Energy meter by USB RS485 converter. I want calculate Power in every hour, daily, week and month but I can't improve my project because of modbus poll rate even I try to write many function. The problem is the modbus poll rate. Example: modbus poll rate every 1 minute. if I try to do math in function. I still can't get any value because of it because it poll in every minute. any guys know how to compare old values with new values after using (node-red contrib-modbus) noded and function or how to calculate it in every hour, daily, and week.