This is getting confusing ?
The OP original post
"My question is, do I just count the pulse per hour and multiply by 378.541 to get liters per hour based on the number of pulses?"
Then
"I am looking for totalizer result."
These are two totally different things
A totalizer accumulates total amount either a continuous accumulation or perhaps over a period of a shift.
Litres per hour is a running flowrate perhaps used to control the flow via a PID or other flow control method.
Which one is it?.
For flow you need to count over a period of time the more pulses per unit i.e. litres/gallons & the shorter time gives you a more accurate flow rate at that sample time, the shorter the sample time the better for instantaneous reading of flowrate for example sampling at 1 hour means the actual flow if varying could in proctice be 99.99 gallons short of actual flow as the last pulse at 100 g/hr could be 1 second after the sample snapshotIf the .
For totaliser again the more pulses per unit gives better accuracy if for example a batching process or shift total.
Here is an example:
If you accumulate the pulses over say a shift of 8 hours & the average flow per hour was 100 gallons then again you could miss the last pulse so the reading could be 100 gal out.
However, if you use say 1 pulse per gallon at 100 gallons per hour then over a shift of 8 hours & the last pulse is missed it would only be one or two gallons out.
As steve bailey has posted for a totalizer every pulse add 100 to the total.
But depending on the max flowrate reduce the volume per pulse so if using standard Inputs then the time between pulses needs to be double that of the max scan time to ensure reading of every pulse.
Again an example is if your PLC has a max scan time of 100ms then the ideal max pulses per second needs to be about 5 to ensure every pulse is caught (or use high speed inputs/interrupts).
Based on max flowrate of 100 gals/h that is 1 gal is a pulse every 36 seconds so you could easily make it 1 pulse per 1gal that would mean a pulse every 0.36 secs per pulse or 360ms.