Got a bunch of issues with FEEDHOLD.
So I added a Stop, Cycle/Start and FeedHold switch to my panel. Started playing around with these to insure they work.
First, issue- Feed Hold is ineffective at quickly stopping the feed. Read up on the forum and sure enough, it's gonna keep right on rolling until the buffer on CSLabs is finished. Actually, it seems more like its going to just coast to a stop some time in the future. But let me finish.
I started to mess around with 3 different Mach 3 Installations.
Mach 3 On Desktop that nothing has been really confirgured at all. Not on any machine.
If you run a program, hit FeedHold, it shows a delay and pretends to stop at the point that it coast to a stop. Press start, it pretends to continue on from that point.
Mach 3 on an actual Knee Mill using an actual parrallel port.
If you run a program, hit FeedHold, it has a significant delay before coming to a stop. Press Start and it backs up to the last known point which is the last line in the G-Code program. Works Okay as long as an arc wasn't being executed when you hit the feedhold.
Mach 3 on the Haas using an external motion controller (cslabs)
If you run a program, hit feedhold, it has a "very" significant delay before coming to a stop. Press Start and it goes to the next point in the G-Code file. Thats a straight line tool path right across the part.
I get a feeling I already know the answers to my questions but would like to hear it. My guess, in desktop mode, works like a champ. On actual machine with parallel port, a semi fix was added to back up and hope for best. On an external controller, all is lost because there is no "packet control" on what was sent, received and whats remaining.
I have been searching this topic and am quite surprised it has not been more vocal. The cycle/Start and Feed/Hold are the most used hard switches on a VMC. Admitteldy, I have had Mach 3 on my knee mill for 3+ years and never really paid attention to this. On the VMC, its different because I have a Z that is very fast and I have a bunch of different tools with different tool lengths. Number one thing I use the Feed/Hold for is Z moves on the first run. I like to hit it just short of contact and do a quick check on the distance to go. Saves a lot of unexpected (operator/programmer error) crashes and lets you do the first run with moderately fast moves. Thats not going to happen on the way it works now. Actually, the way it works now seems to completely make the Feed/Hold about as dangerous as it gets. Unresponsive and unpredictable.
Really hoping someone has insight. Have seen suggestions to use older version of Mach. I'm open to that but would also like to have a clue of what issues I will be facing right out the gate.