Re: EMC-ok and then
Posted by
Jon Elson
on 1999-10-28 12:34:27 UTC
Jan wrote:
but not as easy as on some commercial CNC systems. I started with an Allen-Bradley 7320, a 1978-vintage control
built around a proprietary 16-bit minicomputer. It was obviously designed with the programmers locked in the same
room as the machinists, and very candid interchange between them. At ANY time, no matter what it was doing,
right in the middle of a helical interpolation with cutter diameter and length compensation, you could hit cycle stop, which would
interrupt the cut in progress, hit jog retract, and select an axis and jog direction buttons, retracting the tool so you could change a tool, (I think even change the tool offsets) and then hit cycle start, and it would pick up at the exact place the cut was interrupted!
I thought this was fabulous, and knew how hard it must have been to program this in assembly language to fit in about 8K
words on a 16-bit mini.
Also, you could hit cycle stop or block-by-block to interrupt immediately or at the end of the current block, and then
hit buttons to skip backwards or forwards one block, or continuously as long as you held the button down, or to search
for a specific block number, or skip to a 'search address' (a letter O word, instead of an N word), or to beginning or end
of program. Then, you could just resume from there with cycle start. If you wanted to re-drill a hole, or re-run a
cutting pass, it made things quite easy. You DID have to watch out carefully for offset compensations coming in and out,
and to be sure the G01/G02 modes were the right one for the cut.
EMC certainly makes this a bit more cumbersome, but the latest versions always read through a program from the beginning,
so that if you start from the middle of a program, it finds out what modes are in effect, and what position the machine
needs to be in for the start of the selected block. This can relieve a bunch of frustration and errors when the block
you want to restart from contains a special offset or mode that you are not looking for.
program from the middle, the 'Edit' pull-down menu allows you to edit the program in a very simple way, and the
edit mode contains a 'button' to 'mark program start'. When you select a block and mark it for program start,
it causes EMC to read through the entire program up to that point, then sets the machine to the position and state
it would be in if it had physically executed to that point from the beginning, and then begins executing from that point.
(It would be nice to have a 'skip backwards one block' command, but this makes the motion look-ahead very
difficult.)
Jon
> From: "Jan" <postmaster@...>Yes, I've asked Fred about this numerous times. He has made some significant progress toward making it possible,
>
> Hello all,
>
> EMC-ok:
> Nice to state that EMC works great. O.K. to be honest for the stepper-module, I got a STG-card but at this time of writing no servo's to plug onto it, so I can't talk about the other motion modules. But my believe in Fred's programming-art is growing every time I work with EMC so servos are the next thing to ask at Santa- class. Thanks Fred.
>
> and then:
> we want to do more with it.
> At this moment I'm looking to interrupt (pause and resume) a running program when a bit (S3-S7) on the paraport is going low or high. handsome if we could do this for example to wait for an automatic toolchange or in my case to wait for a welding task (connecting two plastics together) is finished.
but not as easy as on some commercial CNC systems. I started with an Allen-Bradley 7320, a 1978-vintage control
built around a proprietary 16-bit minicomputer. It was obviously designed with the programmers locked in the same
room as the machinists, and very candid interchange between them. At ANY time, no matter what it was doing,
right in the middle of a helical interpolation with cutter diameter and length compensation, you could hit cycle stop, which would
interrupt the cut in progress, hit jog retract, and select an axis and jog direction buttons, retracting the tool so you could change a tool, (I think even change the tool offsets) and then hit cycle start, and it would pick up at the exact place the cut was interrupted!
I thought this was fabulous, and knew how hard it must have been to program this in assembly language to fit in about 8K
words on a 16-bit mini.
Also, you could hit cycle stop or block-by-block to interrupt immediately or at the end of the current block, and then
hit buttons to skip backwards or forwards one block, or continuously as long as you held the button down, or to search
for a specific block number, or skip to a 'search address' (a letter O word, instead of an N word), or to beginning or end
of program. Then, you could just resume from there with cycle start. If you wanted to re-drill a hole, or re-run a
cutting pass, it made things quite easy. You DID have to watch out carefully for offset compensations coming in and out,
and to be sure the G01/G02 modes were the right one for the cut.
EMC certainly makes this a bit more cumbersome, but the latest versions always read through a program from the beginning,
so that if you start from the middle of a program, it finds out what modes are in effect, and what position the machine
needs to be in for the start of the selected block. This can relieve a bunch of frustration and errors when the block
you want to restart from contains a special offset or mode that you are not looking for.
>To simply pause and resume, use the P key for pause, the S key to resume. If you need to go back and restart the
> Can someone point me what to change in the code or more preferable; Jan you mist something, just use S? Fred has included what you want already in his code.
program from the middle, the 'Edit' pull-down menu allows you to edit the program in a very simple way, and the
edit mode contains a 'button' to 'mark program start'. When you select a block and mark it for program start,
it causes EMC to read through the entire program up to that point, then sets the machine to the position and state
it would be in if it had physically executed to that point from the beginning, and then begins executing from that point.
(It would be nice to have a 'skip backwards one block' command, but this makes the motion look-ahead very
difficult.)
Jon