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DF-1 / DF1 protocol is an asynchronous byte-oriented protocol that is used to communicate with most Allen Bradley RS232 interface modules. DF1 protocol consists of link layer and application layer formats. Link layer serial frame is a composition of conventional RS-232 serial frame with the parameters specified as 8 data bits, no parity, and a maximum baud rate of 19200. DF1 is ASCII character oriented protocol and works over half duplex and full duplex modes of communication. ==Application Layer Messages== Application layer message format consists of ''Command Initiator messages'' (request messages) and ''Command Executor'' (reply messages). Important command initiator messages are as follows. * apply port configuration * bit write * change mode * close file * diagnostic status * disable forces * disable outputs * download request * echo * enable outputs * enable PLC scanning * enter download mode * enter upload mode * exit download/upload mode * file read * file write * get edit resource * initialize memory * modify PLC-2 compatibility file * open file * physical read * physical write * read bytes physical * read diagnostic counters * reset diagnostic counters * read link parameters * read-modify-write * read section size * restart request * set CPU mode * set data table size * set ENQs * set link parameters * set NAKs * set timeout * set variables * shutdown 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「DF-1 Protocol」の詳細全文を読む スポンサード リンク
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