(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.

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Modem

Communication

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

JW-20CM

 

 

 

 

 

 

 

 

 

 

 

 

 

PC

Communication control port

 

 

 

 

Bus/interface port

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RAM

 

ROM

 

 

 

ROM

 

 

RAM

 

 

 

 

 

 

 

 

 

 

 

 

S

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Buffer

 

 

 

Data

 

 

I

 

 

 

 

 

 

 

 

RAM

 

 

 

 

 

 

 

 

 

 

 

Bus bonding

 

 

 

O

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

memory

 

memory

 

 

 

 

CTC

 

Communication

 

 

 

CTC

 

 

Interface

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CPU

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CPU

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SIO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Processing of JW-20CM

Processing of PC side

Check PC hardware

Zero-cross

synchronization

8

I/O processing

NORemote communication

complete?

YES

Data exchange with data memory

Remote I/O communication processing

Data exchange with remote I/O master station RAM

PC operation

NO Communication complete?

YES

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)”.

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