Rise Time measures how quickly your espresso machine gets up to temperature. Typically you measure the time it takes to get to within 90% of the target temperature.
Bang Bang controllers usually have a lower rise time but take longer to achieve a stable temperature
Peak Overshoot indicates how far above the target temperature the espresso machine heats up to. You want to minimize this measurement.
The offset looks at the average temperature after the control system has stabilized and compares it to the target temperature.
Settingling time is how long it takes the control system to get and stay within 10% of the target
Bang-Bang Parameters
"Bang Bang" Controls look only at the current temperature and the setpoint. If the temperature is below the setpoint, the heater turns on. If the temperature is above the setpoint, it turns off.