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Author Topic: Lathe - set max RPM for CSS?  (Read 12165 times)

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Offline Hood

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Re: Lathe - set max RPM for CSS?
« Reply #20 on: January 25, 2012, 02:37:31 PM »
G97S***  should turn it back off.
Not sure what you are asking with the other questions.
 To my mind the only really useful CSS is when in G95 as it wiil, or rather should if it was working, keep the chip load constant whilst at the same time keep the surface speed constant.

Hood
Re: Lathe - set max RPM for CSS?
« Reply #21 on: January 25, 2012, 03:30:36 PM »
Intuitively, I expected G94, G95 and G96 to be mutually exclusive modes - any one of the three.
OK. I can wrap my head around 4 mode combinations:
G94 xor G95 and then G96 xor G97

but I still can't get G97 to turn G96 off.....
G97 is accepted by itself on the MDI line w/o error, but the G96 mode indicator does not change.
I've noticed that the mode line can lag state changes, so I looked up LED 107 which is CSS mode.

here is my test sequence results so far:
G96 S400 - LED 107 goes on, mode line shows G96
G97 - led 107 stays on, mode line still says G96

start over and try this:
G96 S400 - LED 107 goes on, mode line shows G96
G97 s400 - led 107 goes off, mode line still says G96

the try this:
G96 S400 - LED 107 goes on, mode line shows G96
G97 S0 - led 107 goes off, AND mode line changes back to G97

I am confused as to what is really happening...


G97 S0 seems to turn off G96 but not just a plain G97 - that leads to more questions:
it seems that maybe G97 requires an s word? 

Since G97 is not in the mach lathe gcode document, I can't look up what the correct syntax is.
Is
1) G97 S00 a single Gcode prep command that takes a S word and the S word has to equal 0 to get G96 turned off?
OR
2) is G97 S0 two separate things in one block? i.e. a pre-gcode G97 command that turns it back to constant RPM mode and the S0 independently sets the target RPM to 0?

if 1), then what is the logic of needing to set G97 RPM to 0...?
If 2) then, I'd expect G97 w/o a sword to work (does not seem to for me).

I hate having to reverse engineer mach due to a simple absence of current documentation....  :'(

Dave
Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com

Offline Hood

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Re: Lathe - set max RPM for CSS?
« Reply #22 on: January 25, 2012, 04:17:02 PM »
Doing the G97 only you should get an error message, it requires the S word, did you not get that?. The G96 seems to hang in the mode line until you do some other command after the G97S**, can be anything such as M5 or a G1 or whatever, I suspect calling a G97S0 is the same as calling the G97S** and a M5 after so that will be why it changes with the G97S0.

Hood
Re: Lathe - set max RPM for CSS?
« Reply #23 on: January 31, 2012, 01:15:23 PM »
Given that G48, G96 and G97 are not in the mach turn 1.84 manual gcode section, I've tried to gather the info I could find re these codes to create a draft addendum.

I've attached the single page and would appreciate any review comments to make it correct.

Dave
Author of the MachStdMill Extensions for Mach3
www.CalypsoVentures.com

Offline Hood

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Re: Lathe - set max RPM for CSS?
« Reply #24 on: January 31, 2012, 05:46:51 PM »
I would say G48 without S word is pointless as your spindle would be limited to max by Mach anyway.

I would say that a feed called whilst in G96 and no spindle feedback (spindle not turning) should throw an error and axis should not move. It seems to at the moment but then again if in G95 and a feed is called and no spindle feedback is seen it will still move. Shouldnt do IMO but does, well at least I think it does, not at machine to test to be 100% certain.
Hood