How calculate pump working hours in micrologix 1400 base on boolean status

I have a pump with ON off status in PLC micrologix 1400
my question is how I can calculate working hours base on ON/off status
How I can use the timer and add time value each time that pump is on or off

Look up the RTO instruction.

This is how I do it. I just display the long integer with an implied decimal point. In this example the pump has 3080.35 hours.

I like that... clean and simple

Okie's example is great, I personally use two cascading counters triggered off of a RTO.DN bit. Counter 1 counts 0-32767, and when it reaches 32767 it increments the second counter and resets itself. The total is then calculated as:

Counter1.ACC + (32767 * Counter2.ACC)

This gives a max of 1,073,709,056 counts, which if your pump lasts that many hours, you've definitely gotten your money's worth. If you really needed more than that you could implement a third counter. I've used this logic frequently for number of starts, flow totalizing, and running hours. Number of start and flow totalizing bypass the RTO, just the start/flow total pulse bit into a one-shot, straight into the counters.

Again, Okie's example is probably a bit more elegant, but I frankly haven't experimented with long integer (LINT) data yet. This was my workaround for the limitation of 0-32767.

I use this method. You would reset your X100 counter however you wish. It has always worked well for me, and can be put into an HMI with relative ease.
Also, the timer base would be 1.0 for the RTO. I set it to 0.01 for fast testing purposes.