[rixed]

Out of curiosity, since I'm interested in industrial monitoring: would you mind telling a bit more about the monitoring infrastructure, esp. how often are those metrics collected and what data protocols are involved in the process?

[generatorguy]

I only know from my own experience and I’m essentially self taught, so I don’t know what industry norms are only what has worked for me and my customers.

The instruments and controlled devices are wired to a PLC such as Allen Bradley control logix or Schneider electric m580. The PLC generally reads the inputs, executes the program, and updates the outputs every 10ms. HMI software running on a computer such as inductive automation ignition, vtscada, wonderware, citect, etc reads data from the PLC to display to the operator and record for history. Protocols are often modbus or common industrial protocol (CIP) which is also called, or some flavor of it, the ridiculous name of Ethernet/IP, but that’s the kind of shit you get in industrial automation.

I generally set the HMI software to record my 2500 values once per second.

During testing it is common to use a data acquisition system that can sample even much faster than the PLC runs, eg 1 kHz.