Hi,
Do you know what figures should be in step pulse and dir pulse and g's ?
The pulse width will be determined by the motion controller so don't worry about that setting, it used to be appropriate with
a parallel port. The g's is another measure of acceleration. So put 1000 mm/sec/sec in the max accel box and the g's
box should be populated by Mach...you don't need to set it.
Just looking at the servo settings on the driver and p1-44 is currently set to 16...do i change that to 5000?
p1-45 is set to 10 do I change that 10 1000?
Thats what I recommend, but they are your servos, you put what you like there. The two numbers form a ratio.
The formula is on page 6-8.
In your circumstance you have an input pulse stream of 2000, F1 and you a Position command of 10000, F2.
according to the formula if N (P1-44)= 5000 and M(P1-45) = 1000 that will be achieved.
You could make N=45 and M=8
Or N=5 and M=1
Or N=120 and M=24
Or N=15550 and M=3100.......you get the idea, the two numbers form a ratio. Its called electronic gearing.
What is happening in effect with N/M = 5 then each input pulse gets expanded to five pulses. Thus 2000 input pulses
will become 10000 Position Command pulses and that will cause to servo to revolve once.
machine weighs 1 ton x can go back and fourth that fast but it is to fast for the long y axis
Those servos are 1 hp each.....why did you buy such hugely powerful and fast servos if you don't need it?
I suggest that if you don't require such high speed then set Machs max velocity to that you are comfortable with,
say 5m/min ....the setting would be 5000 (given the units are mm).
I suggested an acceleration setting of 1000 mm/sec/sec to start with. That is already higher than most hobby machines
but way WAY
WAY less than those servos are capable of. Production machines would commonly have settings
of 10,000 mm/sec/sec up to maybe 50,000 mm/sec/sec, that is somewhere between 1g and 5g. REALLY
REALLY SCARY
FAST. I don't suggest that you go that high but for machining speed and CV following accuracy you want to be as
high as the rigidity of your machine will tolerate. I think its a given that your machine will flop around like a fish LONG
before the servos max out!
adjusting the settings right up did make the machine rock but looks like will have too much movement vibration at higher speed and probably cause inaccuracy
Flexure or lack of rigidity in your machine will cause inaccuracy. The servos may set up a vibration , that what all those
settings are for, PID gains, notch filter settings etc. You have only just scratched the surface....those servos are
EXTREMELY CAPABLE You need to tune the servos to get near maximum performance from them and THEN dial
them back until your machine stops flexing and wobbling. From your description you will have to dial them back to
about 10% of what they are truly capable of.
Craig
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