842
Serial Communications Instructions Section 3-23
Description STUP(237) writes 10 words of data from S to S+9 to the communications
setup area of the Unit with the specified unit address, as shown in the follow-
ing table. When the constant #0000 is designated to S, the communications
settings of the corresponding port will be set to default.
Note Serial port 1 is the port on the Serial Communications Option Board mounted
in option slot 1 and serial port 2 is the port on the Serial Communications
Option Board mounted in option slot 2.
When STUP(237) is executed, the corresponding Port Parameters Changing
Flag (A619.01, A619.02, or A619 to A636) will turn ON. The flag will remain
ON until changing the parameters has been completed.
Use STUP(237) to change communications parameter for a port during oper-
ation based on specified conditions. For example, STUP(237) can be used to
change to Host Link communications for monitoring and programming from a
host computer when specified conditions are meet while execution a commu-
nications sequence for a modem connection.
If the PLC is turned OFF and then ON again after STUP(237) has been used
to change the communications parameters, the parameters will revert to the
previous parameters, i.e., the ones before STUP(237) was executed.
Flags
Indirect DM addresses
in binary
@ D0 to @ D32767
Indirect DM addresses
in BCD
*D0 to *D32767
Constants Specified values only #0000
Data Registers DR0 to DR15 ---
Index Registers ---
Indirect addressing
using Index Registers
,IR0 to ,IR15
–2048 to +2047 ,IR0 to –2048 to +2047 ,IR15
DR0 to DR15, IR0 to IR15
,IR0+(++) to ,IR15+(++)
,–(– –)IR0 to, –(– –)IR15
Area C S
Unit address Unit Port No. Serial port Serial port communications
setup area
00 hex CPU Unit 1 hex Port 1 Communications parameters for
the serial port 1 in the PLC
Setup
2 hex Port 2 Communications parameters for
serial port 2 in the PLC Setup
Unit No. + 10
hex
CJ-series Serial Com-
munications Unit (CPU
Bus Unit)
1 hex Port 1 10 words starting from D30000 +
100 x Unit No.
2 hex Port 2 10 words starting from D30000 +
100 x Unit No. + 10
Name Label Operation
Error Flag ER ON if the values in C are not within range.
ON if STUP(237) is executed for a port whose Communi-
cations Parameter Changing Flag is already ON.
ON if STUP(237) is executed in an interrupt task.
OFF in all other cases.
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