tachometer input

Thread Starter


Joined Apr 6, 2005
Hi to everyone. This is still part of the tachometer, main concern is the input. The tachometer that i am studying has actually four possible variations of input.

I need help to analyze this part of the circuit though I have already obtained some of the output waveform of this part of the circuit (one going to the flipflop and another going to the microprocessor). I basically need to know why my output reading on the tachomter reading varies for every other input.

To give you some details, i place a signal gen at the input 25 Hz to be exact, the output that i read at pin 6 and flipflop is 1500 rpm (that is s=f*60 for a contact input). But when i used a voltage input, the reading is about 2000 plus or minus and is varying at every pulse sent.

The four input i am talking to is voltage input, open collector input, magnetic input and the contact input.

Switches are set in the following manner:
sw1 sw2 sw3
magnetic input on on off
open collector off off off
contact input off off on
voltage input on off off

How do you think the circuit is behaving after this settings. Most especially how could you relate the varying output in the display as compared to the contact input which sends an output in the formula i stated above.

Thanks to anyone who could help. I just need some further classifications on this circuit...