Siemens SINUMERIK 840Di sl Programming Manual page 538

Glossary
Machining channel
Via a channel structure, parallel sequences of movements, such as positioning a loading
gantry during machining, can shorten unproductive times. Here, a CNC channel must be
regarded as a separate CNC control system with decoding, block preparation and
interpolation.
Macro techniques
Grouping of a set of instructions under a single identifier. The identifier in the program refers
to the grouped set of instructions.
Main block
A block prefixed by ":" containing all the parameters required to start execution of a -> parts
program.
Main program
Parts program identified by a number or identifier in which further main programs,
subroutines or -> cycles may be called.
Mains
The term "network" describes the connection of several S7-300 and other terminal devices,
e.g. a programming device, via -> interconnecting cables. A data exchange takes place over
the network between the connected devices.
MDI
Control operating mode: Manual Data Automatic. In MDA mode, it is possible to enter
individual program blocks or sequences of blocks without reference to a main program or
subroutine and to then execute them immediately via the NC start key.
Messages
All messages programmed in the parts program and -> alarms recognized by the system are
output on the operator panel in plain text with the date and time and a symbol indicating the
cancel criterion. The display is divided into alarms and messages.
Metric system
Standardized measuring system: for lengths in millimeters (mm), meters (m), etc.
Mirroring
Mirroring reverses the signs of the coordinate values of a contour, with respect to an axis. It
is possible to mirror with respect to more than one axis at a time.
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Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
Fundamentals