Access or read amperage going to the motors
I'm working on a CNC mill which was retrofitted with LinuxCNC (someone else did it).
It uses a Motenc Lite board, connected to the original VFDs and motors ("Red cap" Fanuc 5,5 Kw, I think it is a 3S model).
There is basically no documentation from who did it, plus I am a rookie on LinuxCNC.
What I need is to access/read the electrical current going to the motors.
I checked the outputs from the motenc and could not find a connection from the board to the VFD. In fact, the VFD does not appear at all in HAL or Classicladder.
Couldn't find any topic related.
Look through all the HAL files to find where (depending on LinuxCNC version) either motion.spindle-speed* or spindle.0.speed* is linked.
There is a choice of spindle speed outputs, rpm or rps, absolute or signed. But one of them will be connected, Follow it through.
But what about the X, Y and Z motors?
For X, for example, Xoutput fluctuates between -1 and 1, depending on the feed. What is confusing me is that Xoutput is connected to a DAC pin, but it is already analog.
And what unit is Xoutput?
You could use "Xoutput" to refer to spindle speed in, though that would be wilfully eccentric.
But, guessing at likely options, it sounds like the signal from the PID to the drive. It could easily be volts, rpm, or -1 to 1 or -100% to 100% duty cycle.
From what you say, it goes to a DAC. you say that it is analogue, but it isn't, it is probably a flaoting point number, bit in HAL it's a binary, digital, number.
bierluiz wrote: But I am still confused in HAL. There should be an output in the Motenc card which sends the signal to the VFD right?
Yes, there will be a HAL input pin (that accepts a value set by another HAL pin, such as spindle.0.velocity-cmd, and converts that to an analogue voltage (or a PWM) on the Motenc output pin.
bierluiz wrote: When you say motion.spindle-speed, do you mean only the actual spindle of the machine, or the ones for the axes motors are also called "spindle"?
You mentioned a VFD, so I assumed that you were talking about a spindle.
The pins created by the motion component are here: