Hi,
Mach4 can handle six coordinated axes, but each of those axes could have as many a six motors, one master and five slaves.
Thus Mach4 could in theory drive 36 motors simultaneously, in six coordinated groups.
In a more normal machine you might have five axes, one with a slave, thus six motors, which would allow scope for another thirty OOB axes, arranged
in groups of six. Thus OB1 is master with up to five slaves. OB2 is master with up to five slaves etc.
All the motors of OB1, master and slaves will operate simultaneously, as will all the motors of OB2, but OB1 and OB2 are NOT coordinated with each other.
This make Mach fairly capable, but most motion control boards cannot do all of that. For instance my ESS has six Step/Dir motor pairs, say four coordinated
axes and two OB axes. The ESS can drive a spindle with Step/Dir which is counted then as one of the six available motor channels. If however it is run as PWM and On/Off
then it is not counted as one of the six motors, nor in fact is it counted as an OB axis. It is if you like a seventh axis but with curtailed control.
To my knowledge there is no Mach4 motion controller that can do anything like the number of motor that mach is capable of. I think it may be possible to have many
more OB motors with Ethercat, which of course does not require a motion board at all. Ethercat can address up to 100 nodes, say 90 motors and 10 IO nodes, should
be enough for most purposes!
Craig