Description:
1 This document annotation describes a case of Mitsubishi PLC to communicate with ASCII RS
2, in this example a PLC as manufactured by Mitsubishi Fx-3G series, the inverter INVERTER FR-D700 Series
3, original content of this example, the reproduced indicate the source, free to use share
The first show at the code, and then analyze the code in order to explain in detail
RS instruction interpreting
RS D10 D50 D100 K20
D10 is the start address of the transmission data, D10 subsequent sequential address order of D11, D12 ........
Denotes the number of transmitted data D50, D50 is 12, so a total of 12 words of data transmission, i.e. the number of transmission data stored in D10 ~ D21
D100 represents the drive receives communication data start address
K20 represents the address of the received data words 20 digits, i.e., the received data is stored in the D100 ~ D119
ASCI command interpreter
ASCI D141 D16 K4
D141 converts the parameters into an ASCII code word 4 stored into D16, D17, D18, D19 in
For example 1234, the value of D141 D16 ~ D19 values shown in the following table
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Communications send what data?
PLC and inverter communication like dialogue between people, is a process of information exchange, just as a telegram,
Header, that is a message, a message title, meaning to tell each other to start sending the message, followed by the message information
Message is the actual data content to express
Trailer, usually used to validate whether the packet data transmission is correct, to tell each other, I send the data has been completed.
E.g. program M140 = ON, D141 = 1234 when, PLC transmission data D10 ~ D21 is stored, a total of 12 characters
(First wrote this, as too have questions, please leave a message, and then answers)