Messages

331

General Mach Discussion / Re: Low voltage on 'step' pin

« on: March 05, 2015, 03:14:42 AM »

I've been measuring with an digital ohm meter which I know isn't the right tool for measuring PWM.  That said, 50% pulse @ 5V reads at 2.5V;  20% High @ 1V, etc.  It's not perfect but it's what I have on hand and it does give some idea as to what's running through the wires.

I suspect you're actually reading the output of the low pass filter fed by the PWM rather than the PWM itself. Imagine though, what your meter would say if you set your PWM at around 0.01% duty cycle?

What's the difference between PWM and Step Signal?

PWM is a signal of fixed frequency with a variable duty cycle. A step signal is a signal of fixed pulse width with a variable frequency. Almost the complete opposites of each other. Like I've said above, trying to measure the voltage of a step signal is like trying to measure the voltage of a PWM without the filter and with a vanishingly small duty cycle.

Anyway - the point is that you should not expect to see a changing voltage on a step signal with a multi-meter. That said it sounds like you're onto it with the 2nd port. Hopefully that'll sort things.

332

General Mach Discussion / Re: Low voltage on 'step' pin

« on: March 04, 2015, 11:29:47 AM »

Not sure I can help but here's a couple of thoughts as I read through your posts.

Powering a BOB from the charge pump signal? You sure you can do that? I never use the chargepump signal but I'd have thought the BOB would require more current than a pin can source.

You don't say what you're measuring the voltages with but your step signal can't be measured with a multi-meter for example. It will always read either near 0V or near 5V depending on your active setting in Mach regardless of whether you're actually stepping or not i.e. it won't change.

Don't confuse a step signal with PWM - they're completely different beasts.

333

General Mach Discussion / Re: Master vs Slave axis pulsing difference on Mach3

« on: March 04, 2015, 06:04:11 AM »

That is a shame Ian, would have loved another reason to beat Brian over the head with regarding V066

Can you not just beat him anyway? 

Pierre - no worries - thanks for the update and hope you find the reason for your waves.

334

General Mach Discussion / Re: Master vs Slave axis pulsing difference on Mach3

« on: March 04, 2015, 05:07:47 AM »

Just loaded up R3.043.066 and tried again with steps/per at 160 and running flat out at 9433 mm/min. (Kernel is actually pulsing at 25.1572 kHz at that speed). Pulses are spot on.

Can you describe your recorder in more detail because I find it curious that two pulsing engines (SS and PP) are apparently giving you the same strange results.

Ian

335

General Mach Discussion / Re: Master vs Slave axis pulsing difference on Mach3

« on: March 03, 2015, 01:46:20 PM »

Hi Pierre

I'm not seeing this here. I'm monitoring my 25kHz PP kernel on a logic analyser at a sample rate of 24MHz i.e. resolving to approx 42 ns (nanoseconds) and slave pulsing on B & C is absolutely identical to X and Y.

There is ONE artefact: after a direction change the first slave pulse lags the master pulse by approx 40us (microseconds). Second and subsequent pulses though are exactly synchronized (within my 42ns resolution anyway).

Ian

336

General Mach Discussion / Re: The 64bit decision...I'd like to hear your opinion

« on: January 08, 2015, 08:52:41 AM »

Hi Brian - I think some weird communication by text thing must have happened.

IMO You've asked a perfectly reasonable question. I'm not aware of anything I've said that could have caused an issue but if I've done so inadvertently I apologize.

It wasn't my intention either to criticize the Proma or the ESS - actually I can't see where I have but just to be clear, I wouldn't do because I've never used either.

I've just tried to explain that it's just a matter of fact that when using ANY external motion controller, Mach has no involvement in controlling the Z axis in response to ANY THC. The only situation where Mach could be a candidate for "blame" is if you're using the PP driver.

337

General Mach Discussion / Re: The 64bit decision...I'd like to hear your opinion

« on: January 08, 2015, 07:48:15 AM »

Brian - I think you may have missed my answer.

338

General Mach Discussion / Re: The 64bit decision...I'd like to hear your opinion

« on: January 08, 2015, 06:58:52 AM »

Please Stirling,
If you have the knowledge and insight then explain to me a problem that nobody has been able to answer. If a program is running and the THC up or down command is given Mach3 will not move Z. Sometimes if I pause the program then resume it will work the rest of the code. 9 out of 10 times tho it doesn't work to the point where I don't even expect it to! I would love to have somebody tell me what is wrong! Thanks, Brian

The thing is that you appear from your earlier posts to be using a Proma and an ESS. Therefore Z movement has absolutely nothing to do with Mach. Simply put, the Proma should be sending the appropriate Up/Down commands to the ESS and the ESS should be sending out the appropriate pulses to the drivers. The only connection with Mach is that the ESS should just be telling Mach where it is every "now and then" so that Mach can update the DROs etc.

So just to be clear. Any erratic behavior you're experiencing is down to either the Proma or/and the ESS. Not Mach.

339

General Mach Discussion / Re: The 64bit decision...I'd like to hear your opinion

« on: January 07, 2015, 07:26:37 AM »

I'm somewhat new to Mach3 so I don't know all the specifics. But from my experience and research it seems the built in Mach3 THC logic is erratic and somewhat difficult to get to work reliably. So, in reading info on other brand THC it seems that the ones with a dedicated plugin would be the most responsive and reliable. I also look for a system that is built and supported by a real person that I can talk English to if I have issues.

My two-penneth if I may.

I've been building THCs for quite a few years now and in my experience Mach's parallel port THC functionality is neither erratic nor unreliable. I actually think it's very good. What ARE erratic and unreliable are SOME of the THC's out there. However, these THC's will be every bit as erratic and unreliable regardless of whether you use the PP or an external controller.

340

VB and the development of wizards / Re: Calculating workpiece angle through probing? (Missing arcus functions)

« on: November 28, 2014, 10:07:26 AM »

atn works just fine as long as you remember it's in RADIANS not degrees.
Hence Tweakie's 180/4*Atn(1) (or of course 45/atn(1))