Chapter 6 Applied Instruction 11. Timing diagrams Mode of receiving data: K0 When data is sent, users can not cancel the sending of the data. If the conditional contact preceding the instruction is not enable, the data will still be sent, but a completion flag will not be set to ON after the sending of the data is complete. Mode of receiving data: 1 or 4 Description: ① Users start/stop the execution of the instruction. ② Time in which data is sent The period of time in which data is sent is not measured. ③ After the first character is received, the time which passes before the next character is received will be measured.
Whenever a character is received, the time measured is cleared. The completion flag will not be set to ON until the time measured is greater than the setting value in D 2 +1. ④ If the instruction is still enabled after users reset the completion flag or the communication flag, the next communication data is sent automatically when the instruction is scanned in the next cycle. ⑤ When the PLC begins to receive data, it begins to measure the time which passes. The communication timeout will not be set to ON until the time measured exceeds 6-425 communication data. SM104 SM105 When a timeout occurs, the PLC sets a communication timeout flag to ON.
Users have to reset the communication timeout flag to OFF by means of a program. After the communication timeout is reset to OFF, the PLC will wait for the next communication data. Communication timeout flag SR210 SR213 If the value in SR210/SR213 is 0, the communication timeout function will not be enabled. The unit of measurement for time is 1 millisecond. Timeout period SM106 SM107 Choice made by COM1 between the 8-bit processing mode and the 16-bit processing mode ON: 8-bit processing mode OFF: 16-bit processing mode Transmisson mode