Operation When Data Is Sent - Mitsubishi Electric FX3U-232-BD User Manual

FX Series PLC User's Manual - Data Communication Edition
Non-Protocol Communication (RS/RS2 Instruction)
8.2.4

Operation when data is sent

When the sending request flag is set to ON while RS2 instruction is driven, the PLC sends the data stored in
the specified data registers
When using communication port ch0, set M8372.
When using communication port ch1, set M8402.
When using communication port ch2, set M8422.
When sending of the data is completed, the sending request flag is automatically set to OFF.
1. Time at which sending is started
When RS2 instruction is executed after the sending request flag is set to ON, the PLC starts to send.
When sending is started, the PLC sends the data stored in the data registers specified by RS2 instruction in
interrupt processing regardless of the operation cycle.
2. Time at which sending is completed
When all send data
*1. The "terminators", "sum check" and "CR + LF" set in the communication format are included also in
the send data.
3. Cautions on sending
When sending data, observe the following cautions
1) While the sending request flag is ON, do not change the amount of send data or the contents of the send
data.
2) Do not set the sending request flag to OFF in a sequence program.
If the send data is changed while the sending request flag is ON or if the sending request flag is set to
OFF in a sequence program, correct data is not sent.
8.2.5 Operation when data is received
When RS2 instruction is executed, the PLC waits to receive. When the PLC receives data from the connected
equipment and receiving is completed, the receiving complete flag is set to ON.
When communication port ch0 is used, M8373 turns ON.
When communication port ch1 is used, M8403 turns ON.
When communication port ch2 is used, M8423 turns ON.
When the PLC receives data, it stores the received data to the data registers
by the RS2 instruction.
While the receiving complete flag is ON, the PLC cannot receive new data.
1. Time at which receiving is started
When the PLC receives data while it is waiting to receive, it starts receiving data.
When receiving begins, the PLC stores the received data in interrupt processing regardless of the operation
cycle.
When the headers are specified in the communication format, however, the PLC starts receiving when it
continuously receives the codes set in the headers. The PLC stores the received data except the headers.
F-68
to ( +m-1).
S S
*1
is sent, sending is completed.
8 Creating Programs (RS2 Instruction)
8.2 How to Use RS2 Instruction
to ( +n-1) specified
D D