Re: [CAD_CAM_EDM_DRO] CNC Controller board less than $495 ?

These are made by several companies, the ones I import are 2M542, made
by JMC whose AC brushless servo motors I import.
A similar one (if not the same one) is also made by for example leadshine.

Google 2M542.
I dont think there is any difference, imo, between one manufacturer and
the other.
These are the ideal controller for smaller steppers, in the Nema 23 /
2-4 Nm range, upto 48 V.

Max voltage 50 V
+ Just use a 48V PSU, easily available, or something as near it as possible
Lower voltage like 24 V just gives less top speed

Good parts (pros):
+Does not activate from back emf
Means it can be backdriven (used manually or by lateh in a
geartrain/leasdcrew) without problems
+Has soft start
Does not gulp enormous current at start up
+ Is silent in use
Steppers dont hiss - noise reduction circuitry kicks in when at standstill
+Has differential wiring - less noise sensisitive.
+Can be connected single ended if the controller (or bob) does not have
differential wiring

First three steps are very important.
Differential can also be very important (mostly is not).

+Has adjustable microsteps
I just set everything at 10 microsteps, which is the ideal compromise

Note:
Steppers are accurate to a full step technically (1/2 step (maybe 1/4
step)).
They are somewhat springy - they try to get to any microstep, but the
torque goes down as more microsteps are added.
A microstep is not accuracy.

Bigger steppers are not better.
-They have more induction = less top speed, less rpm (more torque)
-If you need more torque, gear small steppers at 1:3.
-If you need more speed, go to servos.

In general, my advice is always to use small steppers at 1:3 gearing.
You get better results.

On 24/02/2015 14:35, 'Keith Burton' kb@... [CAD_CAM_EDM_DRO]
wrote:

> Found Pokeys on web easily but not 542 series stepper drivers. A link
> would be appreciated.
>
> Keith

--
-hanermo (cnc designs)