Morris,
The FG command could use a little tweaking, that's for sure. The trick is to write down the X,Y,Z where the machine was stopped, and insert a jog command just above it, with the same coordinates, and the Z set up at 1" or so. Then run the FG command and tell the machine to goto the line # where you put the new J3 command. From there, it will run over to the spot, and gracefully plunge into the work and resume cutting. One KEY factor here boys and girls is to remember to set your move speed in SB3 BEFORE you run the FG command. Since the program will not begin executing until the line number you specify, it is very likely that the machine will run at an undesireable speed, UNLESS you have coded a MS command after the starting line of the FG. If you don't start the FG command at a jog command line, then I can pretty much gaurantee that your router is going to move on an XZ or YZ plane and screw up your part. Perhaps a good suggestion for a future version of FG would be to take the line to start & behind the scenes, insert a J3 command and prompt the user for an appropriate safe Z height. This would eliminate the ramp of destruction moves...
When I used to run SB2, I was always losing steps (since I was just learning) and had to figure out how to get my 0,0 back in case of catastrophic failure. I never ran proxy switches on my machine, so everything is done by eye. If for some reason the machine craps out, zero the tool where it sits (Z2)...then in keyboard mode, move the tool back to your original 0,0 point or a known location. Sometimes I will bore a small hole into the spoilboard with the cutting tool at a known location from 0,0 and write it's location (EG - 12,12) on the spoilboard next to it in pencil. (This technique is for people without proximity switches by the way)...After you have moved the tool to your original 0,0 point, write down the X & Y position shown in the red DRO in SB2 or SB3. It will most likely be 2 negative numbers: -24, -12 etc. Then zero out the tool (Z2). Then FE to look at your file and scroll down until the code reads close to the location you wrote down, but in positive: M3,24.125,11.98,-.25 etc - Observe what is going on in the code, and see if that is where you need to be. Sometimes it is easier to create a new part file (using FE) and copy & paste up to a certain line & run in preview mode. SEE if it looks like the location where you left off. If it does, then go back to that area of the code (original file) and copy the line where you want to start. Hit enter for a blank line & paste it right above the line you want to start cutting. Change the M3 command to a J3, and any negative Z value to a positive. EG - M3,24,12,-.25 should be changed to: J3,24,12,1 - JUST ABOVE this line, enter in an appropriate speed, something like: MS,2,1. Then write down this line number (shown on bottom bar of SB Edit). Now run the FG command, enter in the line number where your NEW MS command is sitting, and click on 'Go'. It will cycle thru your code until it gets to the line you entered. It will highlight the line in SB3 where it will start. If this is the correct line, then click on 'Run From Here' and your back in biz. Don't forget to do a C2 if you think you lost Z position, before running the FG command...and, as with anything else, you should run the FG command in preview mode if you are not certain how it will work.
Hope I didn't make understanding the FG command even more difficult...
-B
