Help understanding fundamentals of linuxcnc

Will something like this make the gmocappy jog button move a stepper motor?

net    encoder-counts    <=   hm2_7i95.0.encoder.00.count
net    encoder-counts    =>   joint.0.jog-counts

gmoccappy has its own methods. See Chapter 5 in its docs
linuxcnc.org/docs/stable/html/gui/gmoccapy.html

Will something like this make the gmocappy jog button move a stepper motor?

The jog buttons in the Gmoccpy GUI will work right out of the box once you have your basic configuration set up. 

 

That will make an encoder work as a MPG
if:

1. Jogging is enabled for joint 0

2. A non zero  joint jog scale is used

3. The machine is not homed
( AFAIK joint jog pins only work before homing
and axis jog pins only work after homing )

 

How is it possible that gmocappy jog buttons work after basic configuration? I Don't see any hal pin connections that make the jog buttons work?

P.s i know they somehow do work, but how and why do they work right out of the box after basic config? This is mostly to help my understanding of linuxcnc

Linuxcnc uses the NML messaging system for interprocess communications
The Linuxcnc python library uses NML
Gmoccappy uses the python library so no pins required 

I hope I have not confused things with my very hardware/hal oriented
view. As Aciera mentioned GUIs typically use the python API for interfacing
with LinuxCNC rather than hal. So you will not see any jog related hal pins
used in the hal file

Note that if you want a MPG using an external hardware encoder 
its better to use hal rather than the python API as its real time
and not dependent on the user interface response time.  This is also true
of physical buttons.

rodw wrote:

gmoccappy has its own methods. See Chapter 5 in its docs
linuxcnc.org/docs/stable/html/gui/gmoccapy.html

 

The only thing I understood from the manual, is that it probably has something to do with these pins : To connect encoders, the following pins are exported:

• gmoccapy.jog.jog-velocity.counts (s32 IN) - Jog velocity
• gmoccapy.jog.jog-velocity.count-enable (bit IN) - Must be True, to enable counts
  
  
  net    encoder-counts    <=   hm2_7i95.0.encoder.00.count
  net    encoder-counts    =>   gmoccapy.jog.jog-velocity.counts 
  
  Am I on the right direction? Or am I misunderstanding things? My thought process is that the statement above connects the stepper motor encoder count(which is connected to the mesa board), to the gmoccapy jog counts. Therefore when you press the jog button -> count increases/decreases -> stepper motor moves

I think you have two types of jogging mixed up.

gmoccapy can jog with a screen button/arrow like most GUis

This is quite different than using an external encoder
to jog.

PCW wrote:

This is quite different than using an external encoder
to jog.

I could never work out why Gmocappy added jogging pins. Using external hardware, this is the correct method
linuxcnc.org/docs/stable/html/examples/mpg.html