Siemens SINUMERIK 840D sl Programming Manual page 649

Backup battery
A backup battery ensures that the → user program is stored retentively in the → CPU along
with specified data areas and bit memory, timers, and counters.
Back-up memory
The backup memory enables buffering of memory areas of the -> CPU without a buffer
battery. Buffering can be performed for a configurable number of times, counters, markers
and data bytes.
Basic axis
Axis whose setpoint or actual value position forms the basis of the calculation of a
compensation value.
Basic Coordinate System
Cartesian coordinate system which is mapped by transformation onto the machine
coordinate system.
In the -> parts program, the programmer uses the axis names of the basic coordinate
system. The basic coordinate system exists in parallel to the -> machine coordinate system
when no -> transformation is active. The difference between the systems relates to the axis
identifiers.
Baud rate
Rate of data transfer (Bit/s).
Block
"Block" is the term given to any files required for creating and processing programs.
Block search
For debugging purposes or following a program abort, the "Block search" function can be
used to select any location in the part program at which the program is to be started or
resumed.
Booting
Loading the system program after power on.
Bus connector
A bus connector is an S7-300 accessory part which is supplied together with the -> I/O
modules. The bus connector expands the -> S7-300 bus from the -> CPU or an I/O module
to the neighboring I/O module.
Job planning
Programming Manual, 03/2006 Edition, 6FC5398-2BP10-1BA0
Glossary
Glossary-3