36 Rev. 08/2018
7.1 Manual and Automatic Operation
Adjusting the opening of the throttle or the openings for the gas supply in the gas mixer can be
carried out via the stepper motor driver in two operating modes:
– Manual operation
– Automatic operation
Manual and automatic operation can be switched via the Manual/Auto switch or via the MICT. In
this case, the MICT overwrites the switch position on the device. You can block the switch-over
feature of the Manual/Auto switch based on particular setting in the MICT. If the status LEDs
Manual or Auto are lighted up, this indicates the operation mode the stepper motor driver is
currently in.
Manual Operation
In manual operation, the external input signals of the master control are ignored. You can use
the two buttons Open and Close to modify the position of the throttle and the openings of the
gas supply for the gas mixer. The stepper motor driver must also be in manual operation for
configuration via the MICT and for transferring settings to the device.
Risk of destruction!
In manual operation, the signals of the master control are not analyzed. If
you make any adjustments in the manual mode with the gas engine
running, make sure that these settings do not endanger the correct
operation of the gas engine.
Automatic Operation
In automatic operation, the stepper motor driver evaluates the external input signals of the
control unit connected. The buttons Open and Close are deactivated. The device cannot be
configured via the MICT. In automatic operation, the MICT can only be used to display the data
and to create log files.
7.2 Reference Run
After the device is switched on or was reset, the VariStep3 stepper motor driver initiates a
reference run. This means that the stepper motor determines its current position. In automatic
mode, the stepper motor subsequently approaches the position defined by the master control.
In manual mode the device connected initially remains in the following position:
– Gas mixer remains in the open position.
– Throttles remain in the closed position.
During reference run, the Offline output is low impedance and the corresponding LED lights up.
The signals of the inputs are not analyzed. A reference run can also be triggered via the MICT.
7 Functions
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