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 Post subject: About imported digital counters.
PostPosted: Sun Sep 03, 2017 6:03 pm 
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Joined: Thu Oct 26, 2006 7:11 pm
Posts: 1293
Location: Maryland
I received the preset digital counters I ordered from Ebay. When I hooked them up, the fun began. It's really quite simple, power in, count input, reset input, relay output. Cut and dry simple.

But with fire on board, the counter, didn't count with a TWT input signal (that's Two Wires Touching). Nothing, nada, the PV count showed 0000.

There is a chain of settings to go through and well some didn't make sense in their Chino-merican language. Digging through the one page data sheet, I realized that there is a prescale function. Let's just say you have a slotted disk interrupter, and it passes 12 holes per product inch. Yup, you can set the counter for 1 inch and will scale the input pulses by 12 to give a 1 inch output count. A great feature but the prescale was set at 1000. It would take 1000 input pulses to register a one count. After I set the prescale to 1.000 I got counts, way too many counts, like noise pulses going ape.

All the way in the bottom corner of the data sheet it shows a switch input with a 1uF capacitor from the input to ground for debouncing. Well, I guess that's fair, since most industrial inputs, like PE, proximity and hall effect sensors are solid state with no bounce. A permanent capacitor would limit the high end counting speed, but a switch input could care less about the capacitor since it is already a slow speed input device! I only wish they had made that more obvious instead of a page of timing drawings for differential inputs that likely nobody will ever use.

This the curse of computers. It cost's little to add a ton of features in software but undocumented they are gotcha's

So, at the end of the day, they work as expected and for $19 ea, they really are a deal, even with their funny papers data sheets.



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Len

“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
"I must be on the way to success since I already have the junk". (Me)
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 Post subject: Re: About imported digital counters.
PostPosted: Wed Sep 06, 2017 11:35 am 

Joined: Mon Dec 06, 2004 1:01 am
Posts: 294
Location: Tennessee
Last year I bought rf frequency counter from ebay. range is from 30hz to 2.5 Ghz, it also displays PL or DPL tones if any. The device has 1 button on it and comes with no instructions. Just press the button, key up a radio next to it and you have th TX freq with PL/DPL tones, auto shut off. even came with the required 9v battery all this for $18..


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