Giant 20' x 3' x 2' router build

[JAZZCNC]

this was the digital driver i think cnc4u have added recently, i have no idea if it is suitable or similar to the EM806 you recommend
Digital DSP Stepper Driver 7.2A, 80VDC or 60VAC CWD872

They are similair to the EM806 in that they use PID technology and can tune them selfs to the motors but they still lack the abilty to go in and tweak thru software in the avent of resonance problems. Now in practice it's likely won't have any troubles but if you do then you still can't do anything about it other than alter the Micro stepping which is less than ideal.
To be honest IMO Leadshine lead the way when it comes to this technology and the others are either cheap copy's or better quality copies playing catch up. My gut feeling is these drives are ok Copies of leadshine technology but can't use the Software option for legal reasons.

Don't get me wrong I'm not saying these drives are no good because I've not used them before but they don't give the same flexabilty or features as leadshine drives. That said, it could be said, they don't cost the same either so your not paying for the features either and if you don't need them why pay for them.? . . . Which is fine if you can be sure your not going to run into resonace problems but like I pointed out before if you do you'll wish you'd payed £15-20 more to be able to tune it out.!

Being in business I applaued your attitude regards supporting helpful business or people and Having help and advise on hand is also valuable but hey you have a Forum full of help and I've offered my number so you have experienced phone support if you need it so I wouldn't compromise my machine just to carry favor.! . . You can still support them by buying other items from them, like there motors which are Ok.

when you mention slaved motors are you talking about two motors on one axis or one motor driving the two screw like i am having?

I mean 2 motors working same Axis that need to run in sync. Imagine the carnage that happens when one motor stalls but other keeps going when 2 motors slaved to the same axis.!! . . . You need some way to tell the other motor to stop as well. The stall detect and it's fault signal provide this abilty.
While the stall detect is mostly of benefit to slaved motors it is also useful to stop the machine when using single motors on each axis in case one axis stalls. This can often save the job if a stall does happen and your not around or quick enough to E-stop the machine before too much damage is done.
(Often Stalls happen at higher feeds, like rapid speeds, when torque is at it's lowest. So you can recover from stall before damage is done because rapid move stalls tend to just mean positional loss and are not engaged in the cut or material.!)