I have an application where I need to measure 2 gas flows with flow meters giving pulses for a certain gas quantity. These pulses can be quite seldom (one per hour or even less) if the gas flow is low.
Also, I need to measure the rpm of 2 motors, where the pulses are much faster (several per second).
Since the gas flow meters have an error that depends on the flow rate, I would like to use a timer to measure the time between the last 2 pulses and in DAQFactory compute the corresponding flow rate.
Now, my question concerns the timer clock and divisor settings. As I understand, using a divisor clock setting, counter0 will become unavailable (which is, by the way, not very clear from the manual). Since I need 2 timers and 2 counters, I will hence need to use a clock without divisor. But then, the lowest frequency i found would be 4 MHz. With a 32 bit timer, this gives a maximum time between overflows of 1074 seconds or 18 minutes, which is not enough in my application.
Is there any way of handling the 4 signals with one U3? Or would the only solution be the use of two units?
Any suggestions are appreaciated!