7i83, Spindle control & hal explanation

With regards to this topic:
forum.linuxcnc.org/38-general-linuxcnc-q...le-control-with-dyn4

Maybe I was asking the wrong question.

Can someone explain how these 3 components would work together for open loop spindle control.

I'm hoping to use a +\-10 control voltage to the spindle/servo drive.
Max fwd is 4000 rpm and max rev is 4000 rpm. For the time being I would to run without the encoder, as I need to order and have delivered the cable to run between the driver & 7i76. The mill has been down for a while.

As an experiment I fed spindle.0.speed-cmd-rps into hm2.7i92.0.7i83.1.5.analogout5 and monitored the voltage across a 2k resistor connected to the terminals. Using the following numbers in my ini I was able to get what I thought was the right voltages.

So I'm a bit confused.

if you want 10V for +4000 RPM and -10V for -4000 RPM I would expect
OUTPUT_MIN_LIMIT = -4000.0
OUTPUT_MAX_LIMIT = 4000.0
OUTPUT_SCALE = 4000

Assuming output scale sets the appropriate 7I83 scalemax parameter
( ini file tokens are largely arbitrary so its hard to know the meaning of
OUTPUT_SCALE without both the hal and ini files available)

Sorry my bad.

The cnc pc doesn't have network connection, apart from what is needed for the mesa comms.

I'll go and throw those numbers in and see what happens, cheers


Ok moving forward.

Using your numbers PCW and feeding spindle.0.speed-out rather than spindle.0.speed.cmd.rps the 7i83 is giving the expected voltages.
If I'm running open loop do I need a pid thread for the spindle ?

I know I probably wont get the best speed control, that would depend on the input voltage seen by the driver and how well it can regulate the speed.

Once again PCW many thanks.