Questions on using a moving gantry style mini-mill...

[JAZZCNC]

If you save the Offsets when closing or by Saving directly in work offsets then G55 will be saved but by default Mach on start up will load G54 so your safe.
If you want G55 or any other offset you'll have to call it with MDI or Thru G-code.

To use different Offset with in one G-code file you'll first need to create the offset and save it.

To see it work Try this.!!
By default your in G54 so set Zero work coordinate. Then Type G55 in MDI now jog away and set Zero again in different place.

Now in MDi Type G54 G0 x0 y0 and it will got back to zero you set for G54. Now type G55 G0 x0 y0 and it will go back to zero for G55.

So say you have one part you need to make but in two different materials. First set up the Zero Offsets for each material G54 & G55.
Then use copy and paste. The first part will most likely have G54 at the begining by default. So paste the code again for the second part and replace G54 with G55.

Now when code runs and gets to second run of part it will use the new Zero at G55.

If you want to keep thses offsets then go into Offests and save work offsets.
To be honest saving Offsets before starting job is a good habbit to get into because if Mach crashes or PC then you lose the offsets and have no way easy way to get back into position. This happens often with parallel port machines when being run hard.