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Author Topic: Mach3 Turn all moves are rapid after feedhold  (Read 4266 times)

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Mach3 Turn all moves are rapid after feedhold
« on: October 01, 2009, 03:42:01 AM »
Wondering if anyone can advise why, after a Feedhold, and then restarting with Cycle Start, all G1 moves become rapids ?  At the moment I have overcome the problem by making the F command non modal so it's repeated in every line.  Perhaps this is a requirement for Mach ?  Any advice appreciated !

Offline Hood

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Re: Mach3 Turn all moves are rapid after feedhold
« Reply #1 on: October 01, 2009, 05:11:30 AM »
Don't have that problem myself but not sure if I have ever done a feedhold at a point where there is no F command.
Will go test and see what happens.
Are you using G94 or G95?



Hood

Offline Hood

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Re: Mach3 Turn all moves are rapid after feedhold
« Reply #2 on: October 01, 2009, 05:20:51 AM »
Just tested and no problems, had one line with a G1 Z** F** then all others were just X or/and Z moves with nothing else and it always resumed at the correct feedrate after a feedhold.
 If you want to attach your xml I will see if I can find a problem with a setting but to be honest I cant think of any at the moment.

Hood
Re: Mach3 Turn all moves are rapid after feedhold
« Reply #3 on: October 02, 2009, 02:18:42 AM »
Many thanks for taking the time to reply. I've been using G96 Feed per Revolution .xml is attached, appreciate if you could comment on it.  The other problem you may be able to advise on is spindle settings. I've tried many different settings to achieve the full 10 volt output to inverter, the problem being that this would drop back about 0.5 volts during rapid moves of X or Z axis and therefore spindle speed would also drop slightly. The settings here work but I also had to alter P.I.D. settings a fair bit as with the default settings it was taking about 40 seconds to get the programmed speed ! There is now some overshoot for a few seconds especially upon increasing spindle speed. Threading seems to work ok though. Many thanks, Nick
Re: Mach3 Turn all moves are rapid after feedhold
« Reply #4 on: October 02, 2009, 02:42:58 AM »
So you have the full picture, here is the offending g code. If you feedhold at any time during T0101 and resume then you will see the feed change from 0.2mm / Rev to 340mm / Rev !   (I expect I have done something very obviously wrong !)

Offline Hood

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Re: Mach3 Turn all moves are rapid after feedhold
« Reply #5 on: October 02, 2009, 09:42:08 AM »
I don't see anything wrong with your xml and in simulation it seems to work fine here.
 As a test can you remove the option to use Feedback in Spindle sync, its on General Config page and see if things work fine or are still screwed. Obviously threading wont work but just want to see if it makes any difference.

Hood
 
Re: Mach3 Turn all moves are rapid after feedhold
« Reply #6 on: October 05, 2009, 02:51:27 AM »
Thank you for looking at this for me.  As you suggested I've temporarily turned off the closed loop control and the problem goes away. I guess I will therefore have to continue with F in each line.

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Re: Mach3 Turn all moves are rapid after feedhold
« Reply #7 on: October 05, 2009, 03:00:26 AM »
Does your spindle rpm show steady in the DRO?
Do you get any messages in the ticker window when using sync?
Hood

Offline simpson36

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Re: Mach3 Turn all moves are rapid after feedhold
« Reply #8 on: October 05, 2009, 04:36:04 AM »
I've had this same issue after a feedhold. I use G95 and no spindle sync.

It is rare that I use feedhold witout following up with a stop, so it was not something that I dug into for a solution. I *think* I am using rev .028 on the mill,, but I would have to check to be sure.