If your printer cuts off part of your image something is wrong with your page setup or page layout tab. 

Setting up a page size in the driver – Use custom size and make the width of your page layout the width of the roll and the length should be how ever much space your LONGEST side needs to layout on the page.  (NOTE: if you have  a 24 x30 on a 24 inch roll it will use the printers built in margins and cut some of your image off.  ALSO if you are printing a 20x30, page set up on a 24 inch roll should be width 24 , length 30.25 to adjust for the printers built in margins and allow the whole image to be printed without clipping). 

Photoshop has limitations on length of print up to 90 inches.  If your image is sized beyond the limitations of photoshop print through a different software (RIP Software will go beyond 90 inches ONyx, Imageprint)

If you have finished this troubleshooting and still have issues, check your cable and connectivity settings