Sharp JW-20CM User Manual page 42

(2) Communication timing
· For communication with slave stations, either of "synchronous" and "asynchronous" can be selected
for operation with the master station PC.
· When "synchronous" is selected, the JW-20CM communicates with synchronize with operation (one
scan) of the master station PC.
· When "asynchronous" is selected, the JW-20CM communicates with slave stations regardless of
operation of the master station PC. Therefore, even if communication of all stave stations is not
completed, the JW-20CM starts data exchange with the master station and PC.
8
Remarks
The slave station will not performs the zero-cross operation even if the master station PC is
"set zero-cross (zero-cross switch 07367 at OFF)".
JW-20CM
Communication control port
RAM ROM
S
I
RAM
O
CTC Communication
control
CPU
Processing of JW-20CM
Data exchange with
data memory
Remote I/O
communication processing
NO
Communication
complete?
YES
Bus/interface port
ROM RAM
Buffer
memory
CTC
Interface
CPU
SIO
Processing of PC side
Check PC
hardware
Zero-cross
synchronization
I/O processing
NO Remote
communication
complete?
YES
Data exchange with
remote I/O master
station RAM
PC operation
8 4
·
PC
Data
Bus bonding
memory