59
4-2
PC Programs
The PC program maintains two data flow directions.
•
PC to Position Control Unit (PCU) command and parameter transmission
uses the Intelligent I/O Write instruction WRIT(87). Commands and param-
eters are differentiated by address inside the PCU.
•
Position Control Unit to PC status reception uses the Intelligent I/O Read
instruction READ(88).
ÉÉÉÉ
ÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉ
ÉÉÉÉ
ÉÉÉÉ
ÉÉÉÉ
ÉÉÉÉÉ
ÉÉÉÉ
ÉÉÉÉ
IN word n + 1
OUT
word n
Command(1)
Command(2)
Command(m)
Flag(1)
Flag(2)
Flag(3)
Flag(l)
Flag(1)
Flag(2)
Flag(l)
Status flag
reception
READ(88)
WRIT(87)
Command
transmission
I/O words
Common RAM
Command
analysis
Status flag
logic
PC
DM area
AR area
Position Control Unit
Data (2)
Data (n)
Data (1)
Commands
ÉÉÉÉ
ÉÉÉÉ
Data
addresses
100 to 999
addresses
000 to 052
ÉÉÉÉ
ÉÉÉÉ
RAM
EEPROM
•
One or more commands stored in the DM area of the PC are transmitted in
a stream to the Position Control Unit, where they are executed sequentially.
The Position Control Unit functions according to the commands sent.
•
Data (parameters) stored in the DM area are transmitted to the PCU and
stored in RAM. Commands can then be used to transfer RAM contents to
EEPROM.
•
For status flag reception, flag allocations are determined by the Position
Control Unit; therefore, the same status flags are transferred to the AR area
each time the Intelligent I/O Read instruction is executed.
•
Because command transmission and status reception rely on the Intelligent
I/O Read and Write instructions, a standard PC program can be developed.
The use of such a standard program is strongly recommended.
PC Programs
Section 4-2
