I'll try and answer this for the third time.....The Beagle is trying to help.
I use a 7i92/776 combo and this is my wiring setup.
Stepper Drv________Driver (7i76)
PUL+ _____________STEPx+
PUL- _____________ STEPx-
DIR+ _____________ DIRx+
DIR- _____________ DIRx-
Bootlace ferrules make wiring so much more easier and neater, not a requirement but it makes life easier when you need to disconnect and reconnect terminals.
With regrads to grounds:
All my PSU DC Neg terminals are not connected to each other
All my PSU AC Grounds are connected to a single nut & bolt connected to the chassis aka STAR Configuration (nothing to do with 3 phase motors). As this is what the regs in my area say.
The only AC mains wiring advice you get off the internet that should be followed is to check your local regs and check with a local Electrician if you aren't 110% sure.
Stepper settings should be available on the data sheet for your stepper motor. If you have no luck ask your supplier, don't assume that the driver is setup correctly.
If you look at the data sheet for your stepper driver it has some good info regarding wiring.
www.omc-stepperonline.com/download/DM542T.pdf
Unfortunately it's a bit spares on the timing values.
Here are some conservative values that might help.
DIRSETUP = 20000
DIRHOLD = 20000
STEPLEN = 5000
STEPSPACE = 5000
Oh and finally with 8 micro stepps you will have 1600 steps/rev ie: (360/1.

*8 = 1600........I wasn't sure whether 1800 was a typo or not.