Communication Format - Mitsubishi Electric FX2N-485-BD User Manual

FX -485-BD COMMUNICATION BOARD
2N
4.

COMMUNICATION FORMAT

This chapter contains diagnostic devices (related flags and data registers) and communication format use with no protocol
and dedicated protocol communications. For details of the RS instruction, refer to the FX PROGRAMMING MANUAL. For
details of the dedicated protocol, refer to the users manual of the FX-485PC-IF.
4.1
Related Flag and Data Registers
Diagnostic
devices
Data transmission delayed
M8121
(RS instruction)
M8122 Data transmission flag (RS instruction)
M8123 Finished receiving data (RS instruction)
M8124 Carrier detection flag (RSinstructionl)
M8126 Global flag (dedicated protocol)
On demand handshake flag
M8127
(dedicated protocol)
On demand error flag
M8128
(dedicated protocol)
On demand Byte/Word flag
M8129
(dedicated protocol)
Selection of 8 bit operations for applied
M8161 instructions ASC, RS, ASCI, HEX, CCD
(RS instruction)
COMMUNICATION FORMAT
Diagnostic
Operation
devices
D8120
D8121
D8122
D8123
D8124
D8125
D8127
D8128
D8129
4
Operation
Communications format
(RS instruction, dedicated protocol)
Local station number (dedicated protocol)
Amount of remaining data to be
transmitted (RS instruction)
Amount of remaining data already
received (RS instruction)
Data header <default STX (02H)>
(RS instruction)
Data terminator <default ETX (03H)>
(RS instruction)
On demand head device register
(dedicated protocol)
On demand data length register
(dedicated protocol)
Data network 'time-out' timer value
(dedicated protocol)
4-1