What Exactly is the Acceleration Setting in Mach 3?

Seriously, I thought it was units per second per second, but I've had several people tell me I had it all wrong.  Recently I tested a machine (inch mode) at 100 in the acceleration setting and when I said I tested at 100iss they claimed that would be like deceleration of a hammer blow hitting a board. 

So what exactly does that figure in the motor tuning mean? 

You are correct it is Units per/sec/sec/. If you are setup in inches then it is Inchs per/sec/sec .

(;-) TP