Sharp JW-20CM - Manual (Page 42)

8 · 4
(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.
SIO
RAM RAM
RAM
ROM ROM
CTC CTC
Buffer
memory
PC
Interface
CPU
S
I
O
JW-20CM
Data
memory
Communication control port Bus/interface port
Communication lines
Modem
Bus bonding
Communication
control
CPU
NO
YES
NO
YES
Processing of JW-20CM Processing of PC side
Data exchange with
data memory
Remote I/O
communication processing
Communication
complete?
Check PC
hardware
Zero-cross
synchronization
I/O processing
Remote
communication
complete?
Data exchange with
remote I/O master
station RAM
PC operation
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)”.
Remarks