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Author Topic: Understanding Mach3 pulses  (Read 1373 times)

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Re: Understanding Mach3 pulses
« Reply #10 on: May 22, 2018, 06:29:02 AM »
Let us hope that the next 15 years are just as 'unproductive'  ;D
Re: Understanding Mach3 pulses
« Reply #11 on: May 22, 2018, 07:43:19 AM »
 ;)

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Re: Understanding Mach3 pulses
« Reply #12 on: June 01, 2018, 06:10:02 AM »
Going back to Ger21's post,  I fully understand that the pulses will probably not be 'clean' pulses, but as you say, the pulse width can be set in Mach3.  So, assuming that a 20 uS pulse is selected, that 'dirty' pulse may consist of several square wave oscillations followed by a low voltage level before the next pulse is sent?  Also, assuming that the pulse is read only on the first rising wave form, would it be advantageous that the first rising pulse as well as incrementing the count also initiates a 'wait' sequence of, say 18 uS before it attempts to read the next pulse?
Re: Understanding Mach3 pulses
« Reply #13 on: June 01, 2018, 06:26:22 AM »
Hi,
have you looked at the pulse stream with a scope? Its not a perfectly regular pulse train like you'd get from a signal generator
but neither do you have to go to such lengths to recover it. Provide you amplified and limited to 0-5V TTL levels then a Schmitt Trigger will retrieve
the signal without difficulty.

Unless your dead set keen on using logic ICs I'd use an Arduino as your counter and binary to BCD and 7-seg decode/latch.

Craig
My wife left with my best friend...
     and I miss him!

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Re: Understanding Mach3 pulses
« Reply #14 on: June 01, 2018, 07:41:00 AM »
I started on the logic IC route simply because I have no experience with microprocessors.  I designed the PCB for the schematic included earlier and had it professionally made.  I have also purchased the ICs, displays and discrete components which, when added together, the cost is significant.  There is an online pcb programme (free) that I used for the PCB design and it is called Circuitmaker.  All of the designs become open source and the relevant circuit is simply called 'CNC OSD' if you should want to view it. The circuit shewn is for one channel only and can be extended to suit the number required as they are all independent.

I will be using a microprocessor for rounding up the number of pulses per millimetre to two decimal places but the unit that I am using (Genie20) is a PIC based chip that is programmed using graphical flowcharts and the code is then generated automatically.   The programming is done in the 'Genie design studio' by New Wave Concepts and is again, free.

Unfortunately, their is no schmidt trigger facility in the programme and so that is why I was considering using the 'wait' function to debounce the pulse.