Axis motor load meters?

[davesnd]

Is it possible without analog inputs to get the value of the voltage being sent to each axis and use it to drive a graph bar on screen giving the operator some kind of idea what is happening with the tool when it is cutting? The Diagnostic screen gives the numbers in the watch windows screen - how can I capture those values every second or two and use them to drive a graph bar? This would be particularly valueable when deep hole drilling with very expensive insert drill heads - you could see when the tool was getting dull or if you had lost the edge on an insert from looking at the load meter. Maybe I need to get a better motion card which has analog in - but being a cheapskate I want to try and make what I have work.

[Al_The_Man]

Normally it is the spindle load that is monitored, giving an indication of load current , some systems take it one step further and the feedrate is reduced when a spindle load is exceeded.
VFD's and most servo drives have an analogue output that is a direct ratio of drive current, this could be taken to an analogue input quite easily.
If you do not have analogue inputs, it gets trickier, although you could get a separate 3 digit digital display from Red Lion or other suppliers as a cheap fix.
Al.

[Karl_T]

You could collect your analog data with a small separate computer program and data aquisition setup. A quick search found this:
http://www.oceancontrols.com.au/data...ition/isee.htm
I see it has example visual basic programs. Write your data to disk.

Then read the data into camsoft. You can do whatever you want.

I've done this sort of project before. The problem you run into is file sharing violation. Make sure the aquiring program closes the file after writing and do it at a certain CPU clock time. Then the reading program (Camsoft in this case) has to read and close the file at a different time.

This would be WAY over my head, but there is a lot of information in the camsoft manual about communicating with outside programs with all sorts of windows calls, dll, etc.

You might ask the great folks at camsoft help about this. I bet its already been done.

Karl

P.S. I surfed the web a bit more... If i were doing this project, I'd get this:
http://www.dataq.com/products/startkit/di148.htm

[keithorr]

A Galil card can have many masters and many slaves. Two apps on the same computer can run concurrently.
An app to save values to a text file would be easy using the Galil command TT (tell torque).
I can write a small application for you with either numbers to a text file or something visual if you need eye candy. The output could also compare values per part to show increased loads with a trend line output and a trip value to hold up further production until a dull tool is replaced.

The analog in daughter boards do not sample as fast as reading the voltage out, and there is discrepancy in analog values. The method is very susceptible to noise from wiring/environment or unstable power sources. Analog input values are completely dependent on the quality of the power source used as the reference. Using a 16bit daughter board to collect information you notice a lot of dancing around in the values which has little to do with what you system is actually doing.
Since your system is always hunting for the best possible outcome the voltage output to your drives is always changing. Your sample data would need to be dampened to show an average trend (value/time period) rather than a simple update every xx ms.

[Karl_T]

...An app to save values to a text file would be easy using the Galil command TT (tell torque).
...

KEWL! There's always another function i didn't know about. Try this in timer.fil

COMMAND MG_TTA 'get torque on A axis
RESPONSE \999 'response to variable 999
\998={(.2*\999)+(.8*\998)} ' exponential smoothing of .2
BAR 1;\998;12


you'll have to set up a bar on the screen and initialize the variables in startup.fil You can use different exponential smoothing values; the two numbers add to 1.

[keithorr]

using variable 998 when it's empty the first cycle? (.2*10)+.(8*0) =2
you'll always be behind the buoy

[Karl_T]

using variable 998 when it's empty the first cycle? (.2*10)+.(8*0) =2
you'll always be behind the buoy

Exponential smoothing is a proven way to smooth noisy data for machine control and statistics. The best exponent depends on many things. A value of .2 will take about 5 cycles to react but give a lot of smoothing. A value of .6, for example, will react quickly but give a lot less smoothing.

My best guess, in this situation, would be to read TT once per second and a reaction after 5 seconds is plenty fast.

karl

[davesnd]

brilliant! thanks guys - now I have functioning load meters on z & x on both of my camsoft lathes. I didn't use the smoothing thing - jumpy is ok with me - I even got carried away and made the bar change colour! from green below 80% to yellow at 80% and red at 90%