Hi there. New UGS user here. I’m trying to get my head around the GRBL and UGS and am making progress. I wrote a Gcode program to machine a 1"square just to see how my accuracy was. I’m working in inches. I stuck the F20 in there and a G20 and then wrote the lines of code. When I hit send the machine takes off like a rocket and then slows down for the second line of the square. I have subbed different feed rates and they do go faster and slower, but not right at the beginning of the program. My question is this. Where do I stick a feed rate to get all the movements to go that slow. Do I need a feed rate for each line? Secondly, If I stick an F10 in there it read at F7.5 in the command window. I tried an F 15 and it read 12.5. Why would it change? I’m coming from Mach3 where you can do most anything.:-). Thanks for any help you can provide.
G0 is a rapid move and does not utilize the F word. Feed rate is determined by a grbl parameter.
G1,G2,G3 motion commands accept a feed rate (F word). If your feed rate doesn’t change you only need one valid command with the F word per g-code file.
G0 X5 (X axis feed rate is determined by grbl $110 parameter)
G1 Y5 F20 (Y feed rate is determined by the F word)
G1 X3 (X feed rate is 20 - F word applies to all axes and is modal - once set doesn’t change unless requested by another motion command)
If you want grbl to report inches you need to set $13=1
Thanks LarryM, that did the trick. I guess I was typing G0’s when I should have been G1’s for this kind of thing. I did the $13 change during the set up, so that was functioning OK.