Mis placed thred
PCW wrote: - Should the default and resting PWM voltage not be 0V?
It is, if you measure STEP4+ relative to ground
Note that STEP4+ will be at +5V before LinuxCNC starts so you need to have a
separate spindle enable (you can avoid this issue by using STEP- and inverting the
PWM pin in HAL)
- For me I am using it to drive a spindle servo - Should I offset my spindles 'stop' voltage so that it thinks -5v is 0V?
No need, this is a wiring issue
- Or should linuxcnc use it's 'offset' function to adjust this internally
- PWM type=2 (up and down) does not seem to work on this. Maybe because of the -5v at stop issue above it can't go lower for reverse.
PWM type 2 does work (but probably not in the way you think)
For normal PWM (type 1) the PWM value is the same for positive and negative but the DIR pin changes (this is called sign-magnitude PWM)
When the I read the flashed firmware on the 7i96 these are the pins it says. I had mine wired up to the +pwm and -PWM.
Reading voltage across +PWM to pin 1 on TB2 (GND) does indeed start at 0 and go positive.
Should the direction be wired similar then as in Dir+ to GND. Or should this be pin 4 and 5 as in the screen shot?
How the exact wiring is done depends on what the PWM pin connects to
Normally you would only use one PWM or DIR pin and the common ground
unless you need differential signals, Note that in no case should you wire
the PWM/DIR or STEP/DIR pins to a common pin on the drive