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Author Topic: Mach4 Spindle At Speed, Spindle Zero Problem  (Read 9109 times)

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Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #60 on: October 21, 2017, 05:06:18 PM »
Hi Craig,

The reason why we couldnt use ISIG_SPINDLE_AT_SPEED is because they assigned it to something but didnt complete the code for it.

Why do u assign a name to a function? because it does something, if it doesnt do anything then why did u assign a name to it? user can use any input(which we did, we used input62) to implement this function.

I assume that they had this idea to implement it to Mach4 but for some reason they didnt, and the extension Rob is talking about is a new version of Mach4 in which Spindle at speed is defined ;)

It has to be like this, when u select Spindle At Speed from the menu and assign it to a pin number, Mach should automatically see it and wait for that signal to turn HIGH after Cycle Start pressed and if not it should display a message which asks user if he/she wants to go on without spindle running.

I was saying this from the beginning and that is the reason why we couldnt use the ISIG_SPINDLE_AT_SPEED and ISIG_SPINDLE_AT_ZERO because they assigned to some function but function is not defined within Mach4 and software does not let user to define that function.

Spindle at speed signal is the best and cheapest way to make the machine know that spindle is at commanded speed, most of the VFDs providing this function, if u dont use it u have to buy a spindle which has encoder installed or u have to install a encoder or rpm sensor to the shaft of the spindle, first one is expensive and second one is dangerous so best and industrial way of knowing that the spindle is at commanded speed is using this function and it must be implemented to industrial version.

Regards,

Hakan

Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #61 on: October 21, 2017, 06:00:34 PM »
Hi Hakan,
Quote
I was saying this from the beginning and that is the reason why we couldnt use the ISIG_SPINDLE_AT_SPEED and ISIG_SPINDLE_AT_ZERO because they assigned to some function but function is not defined within Mach4 and software does not let user to define that function.
Rubbish! The SIGNAL is defined the ACTION is not. The modern programming paradigm is the an object and its action are separate. You create what ever function
you require to achieve the behaviour you want and then you LINK the OBJECT (input signal ISIG_SPINDLE_AT_SPEED) to your desired ACTION ( your function)
In this case we used a particular API call to make our function (mc.SignalWait()) but unfortunately that particular API has limited input range but otherwise
preforms perfectly. If we chose to use a different way to make our function that didn't use that particular API call the we could have used ISIG_SPINDLE_AT_SPEED
throughout.

Quote
Spindle at speed signal is the best and cheapest way to make the machine know that spindle is at commanded speed, most of the VFDs providing this function, if u dont use it u have to buy a spindle which has encoder installed or u have to install a encoder or rpm sensor to the shaft of the spindle, first one is expensive and second one is dangerous so best and industrial way of knowing that the spindle is at commanded speed is using this function and it must be implemented to industrial version.
Certainly using the At Speed or Is Stopped signals provided by VFD is cheap and easy...look you've done it yourself. My VFD and its hardly unique, a Delta, synthesises
and encoder output which can be read by Mach. Its built in...no cost involved. Yes if you require exact and/or physically confirmed rotation then you'll need a tacho
or similar. The At Speed signal cannot determine if the rotor is spinning except indirectly and so would fail a safety test which might be required of a coolant pump
or a lift motor. Such applications require a tacho or indexer, safety requires it and is in effect leaglly mandated by Codes of Practice and various National Standards.

My spindle can use the 'Wait on Spindle to Stabilise' and 'Percentage' functions already in Mach4 for exactly that purpose. You may recall early in the piece I advised you
that you could use either of two methods to achieve what you wanted. You chose to go with the  At Speed/Is Stopped route whereas the other method reqired
you program your VFD to produce a pulse output and have Mach use its inbuilt functions to read and act on it.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #62 on: October 21, 2017, 06:25:48 PM »
Hi Craig,

U know these programming things better than me so i trust your word on it ;)

Quote
whereas the other method reqired you program your VFD to produce a pulse output and have Mach use its inbuilt functions to read and act on it.

How did u program your VFD to produce pulse output?

Regards,

Hakan
Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #63 on: October 21, 2017, 07:13:24 PM »
Hi Hakan,
the output is called 'Digital Frequency Meter' or DFM and has a programmable parameter per attached.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #64 on: October 21, 2017, 07:44:13 PM »
Hi Hakan,
this is pulse output that is equal or at least proportional to the output frequency of the VFD. As you know an induction machine will not rotate at
the frequency on its terminals but at some slower speed determined by the slip. With a good installation and motor the slip is seldom more than a few
percent of the input frequency. This signal is a fair representation of spindle speed.

If however the spindle is stalled for whatever reason the frequency would still be applied to the stator but the rotor would not turn. The output signal
would indicate wrongly that the spindle is rotating. The machine would very likely fault out 'current overload'. The essential point is that the pulse signal
is a reasonable estimate of spindle speed except under fault conditions and potentially inaccurate at start up conditions. If you called for the frequency
to ramp up too much faster than the spindle can accelerate and yet be within its fault current limit the output signal may get to 50Hz say while the spindle
is still trying to accelerate and is spinning at only 40Hz.

Most recent VFDs offer sensorless vector control, the VFD very cleverly uses current fluctuations to guess at the rotor actual speed and position. As such they
can be thought of as a servo. They can't achieve position control and their accurate speed control has a span of 10:1 or thereabouts. Of course a servo with
a proper encoder blows them into the weeds but none the less a very clever use of the digital signal processing power available to manufacturers. My Delta
does sensorles vector control but doesn't provide a derived rotor speed pulse, just the input frequency as above.

The signals At Speed and Is Stopped suffer the same problem, they represent whether the applied frequency is at speed or stopped but it can't actually tell
what the rotor is doing. If it was a matter of safety that the motor was rotating then would would need a device to measure it like an encoder. Even a sensorless
vector control VFD is still a derived measurement and wouldn't satisfy me in a lift application for instance.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #65 on: October 22, 2017, 05:03:52 AM »
Hi Craig,

My VFD is also a Delta VFD-E series and it is sensorless vector control, i couldnt find DFM in the user manual but in my VFD it is called MO1 and MCM i guess, i am using that terminal to get the spindle at speed signal.

From your description i think they are basically the same thing right? VFD is guessing the rpm by the frequency so the result of your way and my way is same.

Regards,

Hakan
Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #66 on: October 22, 2017, 12:24:29 PM »
Hi Hakan,
my VFD is a B series unit. It has the Multifunction Opto Outputs as well, but they are just digital IO, they do not switch on and off that fast
to my knowledge. The DFM and DCM terminals are separate and dedicated to that one job.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #67 on: October 22, 2017, 12:41:32 PM »
Hi Hakan,
just downloaded the Delta E series manual and it doesn't appear to have apulse output.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #68 on: October 22, 2017, 05:04:39 PM »

I couldnt see that either Craig,

but we solved the problem anyway so its ok.

Regards,

Hakan
Re: Mach4 Spindle At Speed, Spindle Zero Problem
« Reply #69 on: October 22, 2017, 11:05:51 PM »
Hi Hakan,
yes you've already got the basis of a solution and the code to do it.

If you had or wanted to adding an indexing unit need not be that hard. This little Hall effect sensor requires 5V, 0V and output all for $2.03 NZD. Add a little
button magnet for another dollar and you're done.
http://nz.element14.com/honeywell/ss411p/sensor-hall-effect-bipolar-to/dp/1784734

Craig
My wife left with my best friend...
     and I miss him!