Basler Electric DECS-400 - Manual (Page 12)

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Message Structure ................................................................................................................................ 203
Device Address Field ......................................................................................................................... 203
Function Code Field ........................................................................................................................... 204
Data Block Field ................................................................................................................................. 204
Error Check Field ............................................................................................................................... 204
Modbus Modes of Operation ................................................................................................................. 204
Serial Transmission Details ................................................................................................................... 204
Message Framing and Timing Considerations .................................................................................. 205
Error Handling and Exception Responses ......................................................................................... 205
Communication Hardware Requirements ............................................................................................. 206
RTU Communication Requirements .................................................................................................. 206
TCP Communication Requirements .................................................................................................. 206
Modbus
™/TCP ....................................................................................................................................... 206
Detailed Message Query and Response............................................................................................... 206
Read Holding Registers ..................................................................................................................... 206
Preset Multiple Registers ................................................................................................................... 207
Preset Single Register (Write Single Holding Register) .................................................................... 208
Response ........................................................................................................................................... 208
Loop Back Diagnostic Test (FC=8) with Diagnostic Sub Function, Return Query Data ................... 209
Loop Back Diagnostic Test with Diagnostic Sub-Function, Restart Communications Option ........... 209
Loop Back Diagnostic Test with Diagnostic Sub-Function, Force Slave to Listen-Only Mode ......... 209
Data Formats ......................................................................................................................................... 209
Generic Types UI8 and I8 .................................................................................................................. 210
Generic Types UI16 and I16 .............................................................................................................. 210
Generic Types UI32 and I32 .............................................................................................................. 210
Floating Point (R23_32) Data Format ................................................................................................ 211
CRC Error Check ................................................................................................................................... 211
DECS-400 Modbus
™ Register Space ................................................................................................... 212
DECS-400 Register Tables ................................................................................................................... 213
Holding Registers for Version Data ................................................................................................... 213
Holding Registers for Metering, Group 1 ........................................................................................... 214
Holding Registers for System Configuration ...................................................................................... 216
Holding Registers for Operating Mode Parameters ........................................................................... 217
Holding Registers for Setpoint Parameters ....................................................................................... 218
Holding Registers for Startup Parameters ......................................................................................... 220
Holding Registers for Limiter Parameters .......................................................................................... 221
Holding Registers for Gain Parameters ............................................................................................. 223
Holding Registers for Protection Function Parameters ..................................................................... 224
Holding Registers for Exciter Diode Monitor Parameters .................................................................. 225
Holding Registers for Relay Parameters ........................................................................................... 225
Holding Registers for General ASCII and Modbus Communication Parameters .............................. 226
Holding Registers for Metering Parameters, Group 2 ....................................................................... 227
Holding Registers for Power System Stabilizer Parameters ............................................................. 227
Revision History ...................................................................................................................................... 231
Contents DECS-400