Pulse counter reset

Hi, im using an ip4 pulse counter module to measure flow rate of a substance for a project, have written my code but can't find how to reset the counter in the manual. Can see which bit should reset each channel but am struggling to successfully put this in to my program.

http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1794-um016_-en-p.pdf

The control bit StartMeasurement starts the measurement of the time period and will reset on the leading edge.

Regards,

is this the BT..../ST bit, because if so ive tried toggling that and it has no effect on the measurement, it just remains at a constant value, even when I alter the amount of pulses im putting through it

and also what would I do if I wanted to reset the counter not the measurement?