How can I configure Mach3 for motor enable with step??

[air-man001]

Hi, everyone....

I want  "MACH3" to do this:

If ( Step Signal ) exist then EnableSignal = 0
If ( Step Signal ) not exist then EnableSignal =1


thank you.

[BR549]

I don't think you can. Mach is a buffered system. The step signals are not available to monitor. Even if they were Machs monitoring is WAY to slow to do what you want.

Just a thought, (;-) TP

[Tweakie.CNC]

I would be relatively easy to do this externally to Mach with one TTL gate and a couple of components but……….

Imagine cutting a near horizontal line which may have 100,000 horizontal step pulses but only 2 vertical step pulses. If the federate was slow the vertical step pulses may only occur every 5 seconds or so.
What sort of time frame would you choose to say that the vertical axis was inactive so it is OK to release the enable signal ?

Perhaps if you could give us some more detail of the reason or application for this a reasonable solution could be found.

Tweakie.

[air-man001]

First .. Thank you BR549 and Tweakie.CNC .

Dear Tweakie.CNC ...  you ask me more detail ..

I will make CNC mill machine .. and used the famous Circuit of Tom McGuire




as you see if step signal come to 4516 , the 4028 "Sequentially" will open the MOSFETs, ok.

but if there is no step signal,will be one of the MOSFETs still open therefore its temperature increases and damage.




the components:

24 volt power source (adapter of an old printer) 500mA
IC's: 4516 and 4028
stepper : 24 volt, 5 Wires
MOSFET : 6N60A
Diode : 1N4007
Zener : 8 volt
Capacitor : 220 micro farad , 35V

[ASC]

I think its definitely possible but I'm not sure if the switch from on to off will happen fast enough to prevent the loss of some steps.  If overheating prevention is your only reason for doing this, wouldn't it be easier to heat sink and actively cool the mosfets?  A little air moving across the chip makes a world of difference.

[Tweakie.CNC]

Tom's excellent work should not be dismissed but control has moved on leaps and bounds with the introduction of cheap stepper motor controller chips from, for example, Toshiba et al.
These chips can incorporate microstepping, automatic current reduction when idle and provision to combat mid band resonance amongst many other refinements over the basic, home constructed driver using discrete components.
It may even be cheaper to purchase the TB6560 and associated components, copy Toshiba's recommended circuit and build your own controller that way. Alternately the multi axis imported boards from China which use the TB6560's may be an even better solution.

If you have ever seen the difference between a stepper controller operating in full or half step mode compared with a stepper motor operating in 1/8th step mode you will know exactly what I mean.

Tweakie.