Inch/Metric Switchover Function - Siemens SINUMERIK 840C Installation Instructions Manual

12 Functional Descriptions

12.36.4 Inch/metric switchover function

12.36.4 Inch/metric switchover function
Regarding NCK under section Parameter, Setting data there is a softkey reading "Inch/metric
switchover" which, when pressed, sends an I code to the MMC application Services which
then fades in the following sub-dialog window (as a safety confirmation) if the corresponding
files exist (necessary to load to the NCK). If in fact the files do not exist, an error message is
generated advising that the files must first be created in the MDD (machine data dialog).
Fig.: Switchover function
Here in the sub-dialog, the user can switch back and forth between the inch and metric
setting. The display shows the current setting and indicates the new setting. The text for the
output fields can be configured by the user (see section Configurability of the switchover). The
dialog can be stopped by pressing the Recall key.
The following actions are executed when the user presses the softkey "OK":
1. The converted data files the names of which are listed in the configuration file (CONFIG)
are sent to the NCK via data transfer.
2. After a successfully completed loading process the services send the I code as task to the
NCK which then converts the TOA and ZOA data according to a specified calculation
method. The conversion can be controlled via a parameter value and the direction of
conversion in the configuration data file.
3. When the NCK has completed the conversion of the TOA and ZOA data, the services
activate a "Power ON reset" signal provided that this function was defined in the
configuration.
The switchover is activated by the NCK via an I code and ends with the acknowledgement of
this I code except for when it is followed by a required Power ON. Since it cannot be permitted
that machine data are changed during a given process, it is necessary that the NCK makes
certain that the I code is sent only in a specific status of all channels and that this status be
continued until the end of the switchover function.
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SINUMERIK 840C (IA)