We have configured a Pi to invoke buzzers that we can set off to announce the start and end of operator break times. They can be invoked from the command line, and I’m wondering how I can get Ignition to basically act like the keyboard that types in those commands.
We have used a Pi connection to have Ignition listen to the output of a particular port, but is it possible to connect to a port that receives text that gets executed as a command?
Use one of the many Modbus tcp libraries on your pi with python to form a modbus tcp device and use the ignition driver to trigger coils on modbus that trigger python call to subprocess.run().
I like to use cheap Click/Click Plus PLCs from Automation Direct for stuff like this. However, you certainly can use a RPi as @David_Stone just detailed.
MQTT could be another option, like Node-Red.
You can also comfortably use IFM IO-link masters for REST API control and access to io link devices directly. In fact you get normal IO with this method too. Saves having to put them in an enclosure.