Use the PIN block with input from a Discrete Input card Pulse Input channel to obtain a flow rate to use in control.
For example, suppose that you have a flow measurement device that represents the flow with a pulsed signal. Configure the PIN block to use the Pulse Input channel's FREQUENCY parameter (pulses in counts per second) to produce an analog floating point value based on the pulse rate which the PID block uses for control.
If you are using the pulse input for control, the FILTER value you select for the Pulse Input channel must be greater than the effective scan rate of the PIN block. The FILTER parameter Properties dialog contains information to help you select an appropriate value.
Remember to set the PULSE_VAL and TIME_UNITS parameters to obtain the correct value on the output (EU/TIME_UNITS format).