How to start Hal in interactive mode

Hi

The tutorial I am attempting to follow says
cd linuxcnc
halrun
halcmd: this last line is meant to show the interactive command line.

But when I run halrun it responds:
halrun: Realtime already running. Use 'halrun -U' to stop existing realtime session.

there is no sign it is in command mode and the command
loadrt siggen
generates this error: -bash: loadrt: command not found

Is this because I have linuxcnc running?
Don't know were to go from here.
Jim
(a idiot proof pin is only as good as your idiot)

Edit: This is a continuation of a earlier post Here about retrofitting my Crusader II control on an Alliant 42vc Mill.

yes, If you need to run a hal command while Linuxcnc is running you can do it from the Halshow window (found in the machine drop down menu in Axis).

You can run halcmd when LinuxCNC is running, but not halrun:

halcmd loadrt siggen

Halrun is not needed when LinuxCNC is already running because its task
is to setup the real time environment (and LinuxCNC has already done this)

The advantage of halcmd over the halshow window is that you have the
command line history and editing features of the shell and that halcmd can be
used in shell scripts.

Thanks Guys

That helps a bunch.

Jim

Andy

What I am trying to do now is run HalScope during a linuxcnc session and tune the servos, ferror, P, FF1, FF2
But I am a knob on and don't know how to capture a axis move on the scope.

Jim

In axis on the pull down menu for Machine, there is an option to open Hal Scope.
You may want to read up on the manuals for Hal Scope.
The first time you open it it will open the configuration window. I usually set it to trace 4 signals sampling in the servo thread, which is plenty for most servo tuning.
You'll also want to click on Configuration in the Machine pull down menu of Axis as well. This is where you can input your changes to P, I, D, FF1, FF2... for testing and then save them permanently to your ini file.
There are several servo tuning tutorials specific to Linuxcnc. Search them out they can be quite helpful.

Todd
I've been reading BJT's servo tuning page and the Hal Manual about HalScope. But I am missing the idea of, do your run a short move program or how do you produce the data you want to chart. Some where someone mentioned you cant get it jogging.
So as usual I am lost.

Jim

JT
What settings for the "trigger" do you use?
Jim