I'm trying to measure the frequency of a pulse train from a hall effect mounted up in my homemade anemometer, a.k.a. "The UFO", with WinScope. I can see the pulse train just fine and there's a hold button that allows me to trap a set of pulses and do the math, but I seem to remember from years gone by using the trigger to get a stable display while a pulse train was still running.

WinScope has a trigger on/off button with adjacent pos or neg buttons and a trigger level slide, but I've tried all possible variations of the above and it just keeps running free across the screen .....

It's been a quarter century or more since I last twisted the knobs on a scope so it's entirely possible I'm doing something stupid. If anyone can point me to whatever it is I'd sure like to know!

Thanx,

SP

 

I have no experience with Winscope. If the oscope has a "normal" trigger mode and also a "trigger hold-off" adjustment then these two features can often bring stability to the scope display.

You can check the manual for examples of using these two features.

hgmjr

 

Thanx for your thoughts hgmjr. There's 2 "delay" sliders, a fine and a coarse, that may perform the hold off function, and I've fiddled with those too.

I'm wondering if the problem is the low frequencies I'm looking at. 40hz or less so far. Could be I'm asking too much from free software. With a max 50msec sweep below 20hz the pulse won't even fit on the screen ....

SP

 

Well, I don't have any signals going into WinScope on this computer, but I have v2.51 installed.

On the menu bar, the 8th button from the left is trigger positive, and the 10th button from the left is trigger negative. The button between the two is trigger off.

Then there's the "Trg" trigger level slider on the far right. If you have trigger positive or trigger negative selected, you'll see the trigger level tic mark on the far left slide up and down when you move the trigger level slider.

 

I'm with ya at v2.51 Sarge and using the very same buttons with no joy. I am getting what I need with the hold button tho. As long as the wind has the UFO spinning fast enough to get over 20hz I can use the cursor to measure the beginning and end of a pulse. Simple subtraction from there.

I don't know where I'll put it but a used scope is on the list.

SP