Smart.Faceplate shows the three values of a control loop together: the process value, the setpoint and the controller output, with the mode of the loop. It is the component an operator opens to change a setpoint or an output.
Nothing requested yet.
requestSetpoint() raises an event and does not change the value. The application sends the write to the control system, and the faceplate updates when the new value is reported. Until then the requested value is shown next to the confirmed value, for example 430.0 → 445.0, and the marker on the bar is drawn hollow.
This confirmation step is the difference between a faceplate and a slider. If the write is rejected by an interlock or the connection is down, the faceplate keeps showing the confirmed value and the request is dropped after pendingTimeout.
A reading whose quality is not good is marked as such, in the quality badge and in aria-valuetext, so a stale value is not presented as a current one.
The compact property hides the trend, the description and the column captions, for a strip of loops along the bottom of an overview screen.