Bosch CL300 - Page 47

Operation
FlexibleAutomation
3−3
3 Operation
3.1 Program Execution
The CL300 user program can be executed in cyclic, interrupt−controlled and time−
controlled manner.
Detailed descriptions of individual program execution steps are given in Chapter 5
Software Description".
3.2 Organizational Structure
The user program is stored in the CL300 RAM, EPROM or EEPROM.
The program memory is a plug−in module in the central processing unit.
The individual CL300 components communicate via 2 bus systems:
D System Bus
D Peripheral Bus
The system bus services the R301 Computer Interface Modules and other intelligent
system modules.
The peripheral bus is the real controller bus for data transfer between peripheral
modules (input/output modules, intelligent peripheral modules) and the central
processing unit.
The central processing unit is organized in bits and words. It has two separate proc
essors for high−speed bit and word processing. The instructions in the user pro
gram and the signal states of the input images contained in the user program are
read,processed, and executed by the central processing unit which subsequently
drives the respective outputs. Following each program end EP, the state of the in
puts/outputs in the process image is updated. For fast acquisition of important sig
nals, the central processing units can directly access the input/output signals. This
operation can be user−determined by a special interface command type.