275
Serial Communications Section 6-3
Related Auxiliary Area Flags
Note In the same way as for the existing NT Link (1:N), the status (communicating/
not communicating) of PTs in the Serial PLC Link can be checked from the
Polling Unit (CPU Unit) by reading the RS-232C Port Communicating with PT
Flag (A393 bits 00 to 07 for unit numbers 0 to 7).
Name Address Details Read/write Refresh timing
RS-232C Port
Communica-
tions Error Flag
A39204 Turns ON when a com-
munications error occurs
at the RS-232C port.
1: Error
0: Normal
Read • Cleared when power is turned ON.
• Turns ON when a communications error
occurs at the RS-232C port.
• Turns OFF when the port is restarted.
• Disabled in peripheral bus mode and NT
link mode.
RS-232C Port
Communicating
with PT Flag
(See note.)
A39300 to
A39307
When the RS-232C port
is being used in NT link
mode, the bit correspond-
ing to the Unit performing
communications will be
ON. Bits 00 to 07 corre-
spond to unit numbers 0
to 7, respectively.
1: Communicating
0: Not communicating
Read • Cleared when power is turned ON.
• Turns ON the bit corresponding to the
unit number of the PT/Polled Unit that is
communicating via the RS-232C port in
NT link mode or Serial PLC Link mode.
• Bits 00 to 07 correspond to unit numbers
0 to 7, respectively.
RS-232C Port
Restart Bit
A52600 Turn ON this bit to restart
the RS-232C port.
Read/write • Cleared when power is turned ON.
• Turned ON when restarting the RS-232C
port, (except when communicating in
peripheral bus mode).
Note: Depending on the system, the bit may
automatically turn OFF when restart
processing is completed.
RS-232C Port
Error Flag
A52800 to
A52807
When an error occurs at
the RS-232C port, the
corresponding error code
is stored.
Bit 00: Not used.
Bit 01: Not used.
Bit 02: Parity error
Bit 03: Framing error
Bit 04: Overrun error
Bit 05: Timeout error
Bit 06: Not used.
Bit 07: Not used.
Read/write • Cleared when power is turned ON.
• When an error occurs at the RS-232C
port, the corresponding error code is
stored.
• Depending on the system, the flag may
be cleared when the RS-232C port is
restarted.
• Disabled during peripheral bus mode.
• In NT link mode, only bit 05 (timeout
error) is enabled.
In Serial PLC Link mode, only the following
bits are enabled.
Error at the Polling Unit:
Bit 05: Timeout error
• CHECK Error at the Polled Unit:
Bit 05: Timeout error
Bit 04: Overrun error
Bit 03: Framing error
RS-232C Port
Settings
Changed Flag
A61902 Turns ON when the com-
munications conditions of
the RS-232C port are
being changed.
1: Changed
0: No change
Read/write • Cleared when power is turned ON.
• Turns ON while communications condi-
tions settings for the RS-232C port are
being changed.
• Turns ON when the CHANGE SERIAL
PORT SETUP instruction (STUP(237)) is
executed.
• Turns OFF again when the changes to
settings are completed.
To Next Page
Loading...
Need help?
General
