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Entry type: FAQ Entry ID: 18410743, Entry date: 05/21/2012

When do you use program simulation or axis simulation with a Technology CPU?

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The Technology CPUs have two simulation modes:

  • Program simulation mode for real axes with connected drive
  • Axis simulation mode for real axes without drive

Program simulation mode
The purpose of the program simulation mode is to test the programmed sequences in the controller, as well as the interaction between different axes. The axis is not moved during this testing!

In program simulation mode all the drives must be connected and working properly. The axis setpoint values are calculated during program simulation, but they are not output to the drive. The actual values are set to equal the calculated setpoint values. The following error is always zero in this mode.

The program simulation can be activated on MC_Power (FB401) by the "Mode" parameter. There, you set the value 4 for the parameter to activate the program simulation mode.

Fig. 1: Setting the program simulation mode

Axis simulation mode
The purpose of the axis simulation mode is to simulate the dynamic behavior of the axis by means of a PT1 element with the sum time constant (T1 + T2).

Thus the axis is available to the user program in the basic functions without the output value being transmitted to the drive. You can also implement the axis simulation mode without a drive.

When you set the simulation status, the complete axis technology is retained and is also available again unchanged when you switch back to the normal mode status in the experts list.

With axis simulation it is not possible to simulate axes with enabled Safety Extended functions. If you nevertheless wish to use axis simulation, you must disable the Safety Extended functions in each TO axis concerned (configuration data in experts list: TypeOfAxis.TechnologicalData.driveSafetyExtendedFunctionsEnabled = NO).
If you use axis simulation when the Safety Integrated functions are enabled, various alarms occur in the Technology.

You must set the following parameters in the expert list to start axis simulation mode. Please note the original values in order to enter them again when you want to switch off the axis simulation mode.

TypeOfAxis configuration data Settings
SetPointDriverInfo.mode SIMULATION
SetPointDriverInfo.outputNumberOnDevice 0
NumberOfEncoders.Encoder_1.encoderIdentification SIMULATION
NumberOfEncoders.Encoder_1.DriverInfo.encoderNumberOnDevice 0
(as from S7 Technology V4.1)
Time constant T1
(as from S7 Technology V4.1)
Time constant T2

More information about the simulation modes is available in the S7 Technology Online Help under the keyword "Operating Modes".

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