This is a live video feed of a Counter Timer Tach module sitting on my desk.
Check out the other videos to see how to configure the tach – this video is just a live demo.
Our Tach input signal is shown here – it’s toggling too fast for our display resolution
… but you can see the rate we dialed in here – I’m going to change that to 30
– and you can see the result on the screen here.
We have the Tach Setup as a 2Hi1Lo Output mode.
That is – Output 2 will be active if the signal goes above our high set point, and
output 1 will become active if the signal goes below our lower set value.
Hence the name – 2Hi1Lo.
For this example we have a lower set point of 20 – that’s set point 1 is 20 – press
the MODE ke and we see that set point 2 is at 40 with 30 being right in the middle, of
course.
Let’s try it: If we increase the rate above the Output 2
set point of 40, then sure enough output 2 becomes active and you have a little LED indicator
here showing that also.
If we drop back down he goes inactive.
If we go below 20, then output 1 becomes active.
Note that “active” in this demo is low – that’s because these are both NPN outputs
or sinking outputs.
Let’s get our rate back up to 30.
The Tach responds and all the outputs go inactive.
What happens if we activate the RESET signal?
Let’s try that – we’ll force the reset signal – you can see the little indicator
here on the tach indicating that the RESET1 is active.
The Tach shuts down.
If we release the RESET signal the indicator goes away and the tach starts right back up
again.
Lets try one more thing, Since the PC is generating the signal - which we can’t actually see
here – its somewhat unstable.
It’s a function of all of the interrupts and background tasks running on the PC, so
it is not exactly 30Hz.
In fact, in order to get this demo to run, we actually had to turn on Averaging.
The Counter Timer Tach is averaging 8 samples, before making a decision.
Let’s go turn that off and see what happens.
Hold down the MODE key for 3 seconds – that will get us into the configuration mode – and
then press the mode key several times to bring up the averaging parameter.
There it is - the averaging parameter is currently set at 3.
That means it averages 8 points before making a decision.
Let’s change that – a 2 would be 4 points, a 1 would be 2 points and a zero is no points.
Let’s see what happens.
Lock it in by pressing the MODE key, press the MODE key again for 3 seconds to flip us
back into the operating mode and now we are running.
We’re at 30, our set points are 20 and 30.
As we get close to the 40 set point though – let’s put it at 39 or 38 – you can
see we get these intermittent responses.
It’s actually varying up beyond 40 cycles per second – that’s how un-reliable the
PC signal is.
Let’s come down near 20 … we’ll put him near 21 – and sure enough – output
1 is telling us that the low end is just as unreliable.
So you can see how important it was to have averaging turned on – that’s a really
handy feature to have in this Counter Timer Tach module.
There are four different Tachometer modes to choose from, so take a look at the manual
to see which one fits your needs.
That’s all there is to using a Tachometer.
Be sure to check out the other videos in this series to get the most out of your Counter
Timer Tach.
And as always, please send us any topics you would like to see covered – or - any other
comments for that matter – we appreciate the feedback!