Mitsubishi QD51 Programming Manual page 675

APPENDIX
Appendix 7.2.2 RS (RTS) control enabled
(BASIC program)
ZOPEN • • • •
ZRECEIVE • • • •
Data
reception result
ZRECEIVE • • • •
Data
reception result
ZRECEIVE • • • •
Data
reception result
ZCLOSE
App - 30
When the RS (RTS) control is enabled, RS (RTS) control signals of the target interface
are turned ON/OFF based on the size of the free area in the receive buffer specified by
the user, allowing the data transmission from the external device to the communication
module to be controlled and requested.
An RS (RTS) control signal is turned OFF when the free area in the receive buffer
becomes one-fourth or less of the total space as data received from the external
device is stored.
An RS (RTS) control signal is turned ON when the free area in the receive buffer
becomes three-fourths or more of the total space because of receive requests from the
BASIC program in the communication module.
A
D51H
Channel open 1
Receive buffer
The free area is
one-fourth or less.
The free area is
three-fourths or more.
3
Communication module
(OS)
RS control
signal
Data
RS control
signal
2
RS control
signal
Data
MELSEC-Q
ON
External device
OFF
ON
App - 30