[Larken]

Lately i had a customer in Arizona with a big machine shop who was having problem. He was running Viper 200's on a big mill conversion.
He had hired someone to come in about a year ago and retrofit the machine with Mach3 and the drives. I remember talking to this guy back then with a problem where he could jog the machine fine but when he ran a file, the drives would trip-out on the first rapid. If he got by the first rapid then the cutting would run ok. We checked acceleration, tuning etc.
Lately i got a call from the owner asking me for help . He got a new guy who knew Mach better and we found the problem.
We did some tests and i had him watch the drives as the program ran. He told me he saw the power lights flick on the Viper drive as the program started to run.
The Problem was, the origional guy had wired the BOB to use one of the output lines to switch the main power to the drives with a Relay. His idea was to have Mach3 Kill the drives if any error or limit was detected.
Mach3 toggles those lines evertime it starts a file. Once we bypassed that relay , everything ran fine.

The bottom line is, don't get carried away with having Mach3 (or any controller) control the power to the system. (Remember HAL in the movie in "2001 a Space Odyssey" ?)

Larry K

[Al_The_Man]

Larry, I would not completely agree with that in the general sense, I think it is a good idea to monitor the health of any controller and ideally place the result in the E-stop string somewhere as is done in most industrial systems, In the Galil and Acroloop cards I use, both have means of monitoring the internal watchdog timer and use this to disable critical power if the system is not running.
I would have thought that this would be especially important in systems such as Mach where the loop is closed externally?
Maybe this is a glitch in the Mach S/W if it does not maintain a specific output when it should?
Maybe using the charge pump to monitor the PC would have been a better choice, if this was not already done?
Al.

[Larken]

Al
For sure your right on a controller like a Galil, where that i/o has been tested specifically for turning off the power.
But the output line on Mach3 is a generic output controlled by possibly an Mcode and is probably best to turn on coolant or a mister.

Mach3 has a Chargepump output, that would have worked better, but still that would cause the drives to be shut down every time the operator stopped the machine with the reset input (not made for Emergency stop).

Larry

[Al_The_Man]

It is my impression that Mach originally intended that the charge pump detected when Mach was booting up or shutting down and held the drives off?
From my limited experience with Mach it appeared that the Charge pump was active the whole time Mach was running, so I used this in the E-stop as a precaution but did not notice any reset?
To me, the bottom line is that there should be a power shut down when ever a critical part of the system fails, such as PC crash etc.
Al.