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F commands in MDI <explained>

Posted: Thu Mar 29, 2018 2:38 pm
by Dave_C
After finishing my Mill conversion I ordered a new computer (refurbished actually) and when I got the new computer I downloaded complete new software versions from the Centroid web page. Upon installation, I saw there were some changes even though I had downloaded my version sometime around the first part of Dec 2017.

I then set up all my settings in the wizard just by looking at the screens on the laptop that I had been running the machine with and the install went absolutely flawless. Or so I thought!

I've ran a full part and posted the picture and it ran as it should!

Today I wanted to grease my ball screws so I started up the mill, homed it out and went to MDI to make a move in X from the Home position to the opposite end of the table. I typed in X0 F10 expecting the table to move at 10 IPM but instead it moved at rapid speed! I tried it several times and no mater what I type, it moves at rapid speed instead of the commanded F speed.

I've made the same moves before I updated the software so what did I miss on this go around? Is there some over ride that keeps the F commands from working? It ran fine when I ran my part!

The differences I see in the new software:

You can set the default X1 move (Parm 40)
You can choose a password or omit one alltogether
On the VCP the feed rate over ride is a + or - and not the rotatory button. (works much faster)

There is a rapid feedrate over ride button! ( I don't know what this one does) My over ride is set to 100% of feedrate and the the display shows 100% feedrate. So somehow I think I have this in some over ride mode even for F commands.

Dave C.

Edited to add Report:

Re: F commands in MDI

Posted: Thu Mar 29, 2018 2:57 pm
by Centroid_Tech
If you only type X0 F10, you forgot to type G1 which is the linear feed G code. By default, when you go into MDI, it's in rapid or G0 mode. Once you add a G1 in MDI, it will stay in that mode as it's modal.

Re: F commands in MDI

Posted: Thu Mar 29, 2018 3:42 pm
by Dave_C
Ok, This just proves one thing. I'm getting to old to do this! :oops:

I suppose it's a good thing I don't have to testify in court how this works because I would have sworn I did not enter the G1 command before but then I may be thinking of how I've used Mach 3 for years.

Oh well, just another day!

Dave C.

Re: F commands in MDI

Posted: Thu Mar 29, 2018 4:20 pm
by Centroid_Tech
Just remember that as long as you enter the G1 the first time, you do not have to enter it again while in MDI unless you command a G0 as it's modal. You could just add a new F command. If you exit out of MDI and go back into it, it will default back to G0 mode so you need to make sure to enter the G1 command.