Mesa 7i96s | Gmoccapy | Spindeldrehzahl regelt nicht

You don't seem to have anything connecting spindle-speed out to the mesa card?

You have wired the spindle-enable to an SSR, but the analogue spindle speed value would normally go to a PWM.

net spindle-vel-cmd-rpm => hm2_7i96s.0.pwmgen.00.value

See this post for examples:
forum.linuxcnc.org/10-advanced-configura...7i96s-analog-spindle

The format of a "net command" is

net signal pin (pin, (pin, ...))

ie a signal name (which has no special meaning, and can be anything you choose) and one or more pin names (which do have meanings, are exported by HAL components, and must exist at the time the net command is issued)

You can only have one output / writer pin per net, but as many inputs / readers as necessary.

Nets can be split over multiple lines, and over multiple HAL files.

So, in your case,
net spindle-vel-cmd-rpm <= spindle.0.speed-out
Is creating a signal called spindle-vel-cmd-rpm which is getting a value from the motion module which is the commanded spindle speed in rpm, but this signal is not being connected to an output pin.

One way to get a full list of all the pins and parameters on your specific system is to add the commands "show pin" and "show param" to the HAL file after all the "loadrt" statements. Then start LinuxCNC from the command line.

To get the default pins of just the Mesa card you can run an interactive halui session (really useful for debugging)
With linuxcnc _not_ running:
If you want to actually run the card and chek inputs/outputs then you need to load, link and start a realtime thread too.

Then you can play about with "setp" and "show" to set and read pin and parameter vaues.

Use "exit" to get out when finished.