Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: IQchallenged on April 22, 2006, 08:05:57 AM
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And do I need one?
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nope you will not need one (at first). The charge pump is a macro that runs all the time in Mach.
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What does it do, And what is it used for?
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It can do anything that you like... I just made a program here : http://machsupport.com/forum/index.php?topic=509.0 to make 125% the max Feed override
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Ooops Brian I think you mean a Macropump ;-)
The charge pump thing is a circuit Mariss at Geckodrive designed to allow an extra safety feature in cnc programs.
The circuit is a one shot circuit that turns on a relay if and ONLY if a 12.5Khz signal is seen on the input. Mach puts out this signal if you can use it.
If the software or the pc crashes then the relay is de-energised, which can cut power to your drives etc.
Also avoids any clunking and motors turning on at bootup.
If you want to play safe then yes you need it.
Wayne...
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You know you are right ;D I don't know why I was thinking macro pump...
thank you for setting me straight
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maybe you were just all "pumped" up about your mill hehehe
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Ooops Brian I think you mean a Macropump ;-)
The charge pump thing is a circuit Mariss at Geckodrive designed to allow an extra safety feature in cnc programs.
The circuit is a one shot circuit that turns on a relay if and ONLY if a 12.5Khz signal is seen on the input. Mach puts out this signal if you can use it.
If the software or the pc crashes then the relay is de-energised, which can cut power to your drives etc.
Also avoids any clunking and motors turning on at bootup.
If you want to play safe then yes you need it.
Wayne...
I just now realized that I had failed to carefully read this post. Thanks Wayne. That's an explanation I think I can work with. I don't know precisely what it means but I think I have a good enough idea of how to check into it. I'm only now to the point (in my build) where I am able to power up my system and watch my three motors run while clamped to a table. I haven't built my chassis yet. I've noticed that when I power up I always hear a clunk. Just one little clunk. I have no idea what it is but I think maybe this is what you're referring to. I hope you're not saying this is harmful.
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Ooops Brian I think you mean a Macropump ;-)
The charge pump thing is a circuit Mariss at Geckodrive designed to allow an extra safety feature in cnc programs.
The circuit is a one shot circuit that turns on a relay if and ONLY if a 12.5Khz signal is seen on the input. Mach puts out this signal if you can use it.
If the software or the pc crashes then the relay is de-energised, which can cut power to your drives etc.
Also avoids any clunking and motors turning on at bootup.
If you want to play safe then yes you need it.
Wayne...
"signal is seen on the input" It will help me a lot when I get the jargon figured out. When you say "input" are you talking about data that I send from my keyboard to Mach?
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no not quite... The charge pump is a small circuit designed by Mariss Freimanis of Geckodrive which has an input. This input is connected to an output on the printer port which has been assigned as the Charge Pump signal.
When Mach is running and not in an error state this output has a 12.5kHz pulse appearing on it.
The circuit mentioned above, monitors this signal and if it dissapears for any reason opens a relay, this relays contacts would normally be part of the external E-stop chain. So if it opens your drives etc could be disabled.
Wayne...
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Is the charge pump circuit schematic available anywhere ? I saw it once, several months back on the artsoft site, but I can not find it now when I need it.
Thanks,
Joel
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Here you go!
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Awsome, thanks for the FAST replay....
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And do I need one?
Depends what system you've got and how it's set up but in my opinion anything that is connected to the parallel port of a PC needs one or something similar. If you can remember the days when a printer was actually connected to these ports everytime you switched the computer on the printer would burst into life for a few seconds then go quiet again. This was due to port testing being done as the PC got ready to do work. So if you now connect a bit of drive circuitry and a motor to the same port then the likely hood is it will also burst in to life in an un predictable manner every reboot of the PC. The other big problem is PC crashes, during this time everything or nothing maybe being whizzed out the printer port and obviously again the motors may act in a dangerously unpredictable manner. The gents above have described how the charge pump works quite well so I'd just add this. There is a part of the mach software that ensures there is a 12.5KHz signal on a pin of the parallel port whilst it has control of the PC and the port the chances of this 12.5KHz signal appearing during reboot or PC crash is v v unlikely so it is a safe way of ensuring your motors only receive a signal to move when Mach has control.