I have had a problem with Mach3 for years now in that sometimes at the end of a program the feed rate override goes to maximum (1500%).  What this means is the next time I run the program, the feed rate is not correct.  I can manually cancel the feed rate override with the Reset Button or reboot Mach3 or manually type in the desired feed rate.  What I want to do is put a feed rate override command at the beginning and the end of all my programs in an attempt to overcome this annoying problem.  I note that there is an OEM Code for Feed Rate Override Cancel Button (1014) but I don't know how to integrate this as a command into my programs.

If this can be done it will solve another annoying problem of Spindle speed going to a initial speed higher than the commanded speed which can also be corrected with a manual press of the Override Reset Button.

What I have in mind is:

M3 S500 (Spindle goes to 640rpm)
Issue Reset Command here (Spindle drops back to 500rpm)
Perform cutting tasks until Program End
Issue Reset Command here (to cancel any spurious Feedrate Override that may occur)
M30
%

Is there an easy way to do this?

Thanks

Chrisjh

Do you have any custom macros using # variables, if you do you may be overwriting some of the system variables and causing the override problem.

Graham

Hi Graeme,

I found the problem with random Feed Rate Overrides.  It was my code!

I was calling CSS (G96) along with Feed/Rev (G95).  This appears to confuse Mach3.  I deleted the G96 call and the problem went away.

However, the problem of spindle speed has always existed on both my mill and lathe.  I have overcome this bug in Mach3 by issuing the following sequence:

M3 S500 (The spindle starts and settles at 640rpm)
G04 P2 (Stabilize RPM)
S500 (the spindle slows to the correct speed of 500rpm)

What I was hoping for was a solution to the spindle speed issue by substituting a "reset" command in lieu of the second S500 command.  I guess that it is not that important as I already have a work around for it.

However, it would be nice to understand why Mach3 behaves like it does with initial spindle speed.

Regards

Chrisjh

You could add your fix code to the M3.m1s macro and then every time you call M3 in your program it will correct the spindle speed, I believe the problem has been sorted in Version 4.

Graham