http://www.aaa3.net/how-to-scale-viewport/

AUTO CAD ploting?
I need to print my site plan in 1″:50′.when i set the scale when in the viewport it just shows me a peace of my drawing because is to big to fit in the page.Could you please give me instrution how to set up the scale correct or the page?I have printer that prints 8.5 by 11 so I want to print few pages and then tape them together.please help
It sounds to me like you have everything right. Remember that you will only be able to print 425’ x 550’ (assuming no borders) at a time on an 8.5 x 11 sheet, using 1:50 scale. If your drawing is larger than 425’ x 550’ (and I am because you stated that you want to print on to multiple sheets) then all you have to do is input the scale 1:50 not 50:1,double click in the viewport and pan to the corner of your drawing and print that portion. Now double click in the viewport and pan to the next section.
*Be very careful to not accidentally zoom in or out while you are panning the drawing by moving the mouse wheel.*
Hope this helps
Autocad Fields that Show Viewport Scale