Omron CJ - INSTRUCTIONS REFERENCE MANUAL 07-2009 Reference Manual page 877

3. Instructions
Hint
• Depending on the external device, it might be necessary to set a send delay when sending data with
TXDU(256). If a send delay is required, set or adjust the delay time in the allocated DM Setup Area.
Precautions
• TXDU(256) can be used only for a Serial Communications Unit's serial port that has been set to no-
protocol mode.
• Transmission is only possible when the Communications Port Enabled Flag corresponding to the
communication port number that is used (A202.00 to 202.07) is 1 (ON) and the TXDU Instruction
Executing Flag (allocated DM setup area) is 0 (OFF).)
• Nothing will be sent if 0 is specified for N.
• TXDU(256) uses a logical port (because it sends an internal FINS command) to output a send
sequence command to the Serial Communications Unit (version number 1.2 or later). Since
SEND(090), RECV(098), CMND(490), PMCR(260), and RXDU(255) also use logical ports 0 to 7.
• TXDU(256) cannot be executed for a logical port if that logical port is already being used by one of
those instructions or another TXDU(256) instruction.
To ensure that TXDU(256) is not executed while the logical port is busy, program the port's
Communications Port Enabled Flag (A202.00 to A202.07) as a normally open condition.
• TXDU(256) can not be executed while the TXDU Instruction Executing Flag (bit 5 of n+9 or n+19,
where n = CIO 1500 + 25
for the port before the first TXDU(256) is completed, program the port's TXDU Instruction Executing
Flag as a normally closed condition.
840
unit number) is ON. To ensure that another TXDU(256) is not executed
CS/CJ/NSJ Series Instructions Reference Manual (W474)
CPU Unit
TXDU
TXDU