In general:
Determination of a physical variable of a process and further use at another point. This is generally a feedback control, but may also be data collection, for example.
In control technology:
In closed loop structures the signal flow path leading from the output to the input. Likewise, the action it imparts and its technical design R. are also stated (DIN 19 226).
The task of the feedback in feedback controls is to check that the actual value and the setpoint match in a control circuit using the output signal.A measuring device is normally necessary for this.
Depending on the type of feedback signal required, a distinction is made between
Mechanical feedback:
using mechanical elements, such as linkages, measuring spindles or feedback springs.
Hydraulic feedback:
which uses a fluid signal, normally the pressure.
Electric feedback:
from electric signals, which are generally taken from a mechanical (fluid) variable using appropriate measuring devices. However, it can also be determined based on algorithms from mathematical models.
Another characteristic used to distinguish between feedbacks is the physical variable that is to be fed back. In fluid technology, this is primarily the location (path), force (pressure), velocity, acceleration, amongst other things.