Siemens SINUMERIK 840D sl Function Manual page 338

G2: Velocities, setpoint / actual value systems, closed-loop control
7.4 Setpoint/actual-value system
If the axis is not referenced (at least in the current control measuring system), then the related
monitoring is not active if MD36510 = 0 or if neither of the two measuring systems in the axis
is active/available.
Types of actual-value acquisition
The used encoder type must be defined through the following machine data:
MD30240 $MA_ENC_TYPE (type of actual-value acquisition (actual position value))
Simulation axes
The speed control loop of an axis can be simulated for test purposes.
The axis "traverses" with a following error, similar to a real axis.
A simulation axis is defined by setting the two following machine data to "0":
MD30130 $MA_CTRLOUT_TYPE[n] (output value of setpoint)
MD30240 $MA_ENC_TYPE[n] (type of actual-value acquisition)
As soon as the standard machine data has been loaded, the axes become simulation axes.
The setpoint and actual value can be set to the reference point value with reference point
approach.
The machine data:
MD30350 $MA_SIMU_AX_VDI_OUTPUT (output of axis signals with simulation axes)
can be used to define whether the axis-specific interface signals are to be output on the PLC
during the simulation.
Actual-value correction
If actual-value corrections performed by the NC on the encoder selected for position control
do not influence the actual value of another encoder defined in the same axis, then this encoder
is to be declared as "independent" via the following machine data:
MD30242 $MA_ENC_IS_INDEPENDENT
Actual-value corrections include the following:
● Modulo treatment
● Reference point approach
● Measuring system comparison
● PRESET
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Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions