GRBL Settings

I'm setting the different parameters in GRBL (9j) and have a question about these setttings...

$110=500.000 (x max rate, mm/min)
$111=500.000 (y max rate, mm/min)
$112=500.000 (z max rate, mm/min)
$120=10.000 (x accel, mm/sec^2)
$121=10.000 (y accel, mm/sec^2)
$122=10.000 (z accel, mm/sec^2)
$130=200.000 (x max travel, mm)
$131=200.000 (y max travel, mm)
$132=200.000 (z max travel, mm)

My X&Y are 1/2"-10 5 start lead screws and my Z is a 16TPI lead screw. I would, at first, like to set very, very conservative acceleration rates. I'm not sure what the x max, y max and z max settings control. Is the x max travel, y max travel, and z max travel settings defining my workspace?

Tnx,