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MELSEC-Q
11 INSTRUCTIONS AND FUNCTIONS
Specifying communication control parameters
Control table format definition
Element position
Item
Description
%(0)
Processing code
Specify the processing code.
%(1)
DC control, control
by signals
Specify the DC control method in the lower byte
and the signal control method in the higher byte.
%(2)
Dummy data
The specification is not necessary (work area
used by the system).
Processing Code 18
%(3)
Receive buffer
Specify the size of the receive buffer.
Reading communication control parameters
Control table format definition
Element position
Item
Description
%(0)
Processing code
Specify the processing code.
%(1)
DC control, control
by signals
Read the status of DC control into the lower
byte and the status of the control by signals into
the higher byte.
%(2)
Dummy data
This data has no meaning (work area used by
the system).
Processing Code 19
%(3)
Receive buffer
Read the size of the receive buffer.
• It is possible to set or read communication control parameters of an open
communication channel using these codes.
• Specify 18 for the processing code in order to set communication control
parameters.
Specify 19 for the processing code in order to read communication control
parameters.
• Specify the control by signals in the following manner, using the higher 8 bits of
%(1).
1
2
3
0
(Bits marked with X are ignored.)
RS (RTS) control
DTR (ER) control (ignored in RS-422)
CS (CTS) control (ignored in RS-232C)
DSR (DR) control (ignored in RS-422)
1: Control
enabled
0: Control
disabled
1: The CS control is enabled in case of RS-232C regardless of the specified data.
1
• Specify the DC control in the following manner, using the 1st and 3rd bits in the
lower 8 bits of %(1).
1
2
3
0
(Bits marked with X are ignored.)
DC1/DC3 reception control
DC1/DC3 transmission control
1: Control
enabled
0: Control
disabled