Mazak Micro Slant 15 Retrofit

smc.collins wrote:

  The 7i49 converts the resolver AC waves into a square wave encoder signal basically. It's handled with discreet logic at the board level. AFAICT linux CNC doesn't know the difference between encoder types at the signal processing level. 

The 7i49 actually passes the resolver angle digitally in to the driver as a number. The HAL driver converts that to a numerical angle and simulated encoder counts (but not, at any point, into a quadrature signal) 

 

smc.collins wrote:

I'd have to ask PCW, my gut tells ne that the resolver input gets slapped with clipping diodes to a square wave it then looks at the zero crossings, and converts that into a count cycle and calculates angles against a tpu in the asic.

but that's how automotive stuff handles those kinds of signals. 
 

The zero crossings don't tell you much,  it is the relative amplitudes of the two outputs that indicate the angle, and there is often only one electrical cycle per shaft rotation. It is necessary to measure analogue voltages. 

For a 5V excitation voltage the output at 0 degrees of shaft rotation might be a 5V p-p 10kHz signal on the S pair and a 0V p-p signal on C. 
Then at 45 degrees it would be a 3.53 V 10kHz signal on the S pair and also 3,53V p-p signal on the C pair. 
At 225 degrees rotation there would be a signal that looks identical to 45 degrees, but out of phase with the excitation voltage. If the voltages are sampled at the peak of the excitation signal then the measured amplitude would be -3.53 on both. 

The 7i49 manual says "The 7I49 uses a oversampling A-D followed by a tracking filter." 


 

Using mach3 to control a robot arm is utter waste of time.
Trying to use mach3 with resolvers is suicide.
Do not know how to explain that shorter.

Got some time last night to wire the encoders on both axis, found the drive enables and did some tests, but this is going te be tough, i can not remove the motors while doing initial tuning.
Have to figure out the encoder scale, that is easy, then try to figure out the correct directions, this is tricky as last night i did change the encoder direction and the Z axis moved over 70mm till i disabled the drives!
Not smart enabling those manually, 1.5KW motors on ballscrews can do a lot of damage.
If i get the chance, i will wire enables to Mesa 7i77 or 7i84 and do some tuning.
Also, the drives have switches labeled P, 0, V, pretty sure i have to set those to V now, they are in the P possition. Guessing those are for Position and Velocity mode....

tommylight wrote:

Not smart enabling those manually,

No, this certainly seems like a situation where you want an f-error to turn things off. Quickly. 
 

By manually, i do mean holding the enable wire by hand touching the ground!
I have a stinking sensation LinuxCNC is much faster at turning those off, i need to touch the wire, hear the motor screaming, remove the wire, in my youth i would think about 0.5 seconds, now probably a lot longer!
I was not sure those are the enable wires, now i know.
More fun tonight, hopefully, spent half day chasing and removing cables from the big plasma i am working on, lost about 2Kg jumping up and down the machine.