flowmeter with pulsed output

I've read most of the posts regarding flow meters. I think I am over looking something. I am programming a Proface touch screen that has logic capabilities. There is a TM075-N-P flow meter by Great Plains installed. This device provides a pulsed output. The device states 37-370 Hz, 1100 K factor and 2 - 20 gallons per minute.
What I am trying to figure out is how do I calculate the GPM based on this data? I am not sure what the K factor means? If I use the digital output to a HSC and count the value to 1 minute, how do I know the gallons?

The K-factor is the number of pulses per gallon - it's got to be in the manual (?). So if you measure the number of pulses in a minute, divide by the K factor, that should be gal/min.

Pulses in one minute [pulses/min]​

Q [GPM] = ---------------------------------

K-factor [pulses/gal]​

Thanks. I figured it had to be easy.

A HSC is probably not needed in your application.
at 20 gallons / min thats 1 gallon / 3 seconds a standard input would even handle 1/10 of a gallon pulse rate