Siemens SINUMERIK 828D Function Manual page 355

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 have 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
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
G2: Velocities, setpoint / actual value systems, closed-loop control
7.4 Setpoint/actual-value system
355