Unable to derive a logic for machine production count estimate

I have a current time-current graph of a machine. Based on the graph I can identify when the machine was on and when it was put to maintenance or tool change. I want to automatically identify the maintenance patterns and remove peak values from that. And with the remaining data (when the machine is on) I want to calculate the production count.

I have the cycle time of the product.

So basically my formula should be something like : Production Count = (Total time - Maintenance time) / Cycle time

I am stuck at removing the maintenance patterns from the graph.

The attached image below is the graph where machine has been on for sometime and then it undergoes maintenance :

Graph with half on time and half maintenance

The attached image below is the graph where machine does not undergo maintenance at all :

No maintenance

I want to program the above in PHP. I can import the csv file in php and interpret the data, but am unable to derive a logic for the above. I can identify the maintenance pattern when I see it on the graph as shown above, however programitically I do not understand how to achieve the same.

I have tried setting a thresh hold value, below which the data is ignored however this approach is not accurate as when the machine is on, it often fluctuates below and above the threshold value.