Mitsubishi MELSEC LJ71C24, Руководство пользователя

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6 SETTING AND WIRING
REMARKS
(1) Confirmation of RS-232 control signal status
Each status of the control signals, ER(DTR), DR(DSR), RS(RTS) and
CD(DCD) can be confirmed in RS-232 control signal status (address:
254
H
/264
H
).
Buffer memory address
CH1 side CH2 side
Bit position
254
H
264
H
b0 RS(RTS)
b1 DR(DSR)
b2 ER(DTR)
b3 CD(DCD)
b4 CS
(CTS)
b5 CI(RI)
b6 to b15 —
(2) Designation of RS and DTR signal status
Normally, the ON/OFF status of the RS(RTS) or ER(DTR) signal is set by the
C24.
To specify the ON/OFF status of the RS(RTS) or ER(DTR) signal, turn
ON/OFF the corresponding bit of the RS or DTR signal status designation
(address: 92
H
/132
H
).
1 2 3 4
1 The RS(RTS) signal is controlled by the C24 in the following cases. (Ignore setting contents.)
• When data are communicated with half-duplex communication
• When communication time and the RS and CS signals are controlled by the modem function
2 The ER(DTR) signal is controlled by the C24 in the following cases. (Ignore setting contents.)
• When the DTR and DSR signals are controlled
• When data are communicated by the modem function
3 After writing data to the buffer memory, a lag of 0 to 20ms occurs until they are reflected in the
signal.
4 When a functional protocol, RS/DTR signal status specification (protocol No. 204 to 207), is
executed with the CPRTCL instruction, the corresponding bit of the RS/DTR signal status
specification (address: 92
H
/132
H
) turns on or off.
For details of the functional protocol, refer to Section 12.3.1.
POINT
Control the RS(RTS) and ER(DTR) signals with the system that includes the C24.
Controlling the RS(RTS) and ER(DTR) signals by the user may cause data
communication errors.