Setpoint/Actual-Value System; General Information - Siemens SINUMERIK 840D Function Manual

2.4

Setpoint/actual-value system

2.4.1

General information

Control loop
A control loop with the following structure can be configured for every closed-loop controlled
axis/spindle:
Figure 2-1
Setpoint output
A setpoint telegram can be output for each axis/spindle. The setpoint output to the regulator is
done on the controller.
Actual-value acquisition
A maximum of two measuring systems can be connected for each axis/spindle, e.g. a direct
measuring system for machining processes with high accuracy requirements and an indirect
measuring system for high-speed positioning tasks.
The number of encoders used is recorded in the machine data:
MD30200 $MA_NUM_ENCS (number of encoders)
In the case of two actual-value branches, the actual value is acquired for both branches.
The active measuring system is always used for position control, absolute value calculation and
display. If both measuring systems are activated at the same time by the PLC interface,
positioning measuring system 1 is chosen internally by the controller.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
G2: Velocities, setpoint / actual value systems, closed-loop control
Block diagram of a control loop
2.4 Setpoint/actual-value system
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