IMR03A07-E4
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3. PARAMETER SETTING .................................................... 3-1
Chapter 3 describes how to set up parameters necessary for the host communication.
3.1 Setting of Communication Parameter ........................................................... 3-2
3.1.1 Description of each parameter ........................................................................................ 3-2
3.1.2 Setting procedure ............................................................................................................ 3-4
3.2 Selection of Communication Data Type ....................................................... 3-5
3.2.1 Communication data type ............................................................................................... 3-5
3.2.2 Description of each parameter ........................................................................................ 3-6
3.2.3 Setting procedure ............................................................................................................ 3-7
3.3 Communication Requirements ..................................................................... 3-8
Processing times during data send/receive ..................................................................... 3-8
RS-485 (2-wire system) send/receive timing (RKC communication) ............................... 3-9
Fail-safe ........................................................................................................................... 3-9
4. RKC COMMUNICATION PROTOCOL .............................. 4-1
Chapter 4 describes the RKC communication protocol.
4.1 Polling ........................................................................................................... 4-2
4.1.1 Polling procedures .......................................................................................................... 4-3
4.1.2 Polling procedure example .............................................................................................. 4-7
4.2 Selecting ....................................................................................................... 4-8
4.2.1 Selecting procedures ...................................................................................................... 4-8
4.2.2 Selecting procedure example ........................................................................................ 4-12
5. MODBUS PROTOCOL ...................................................... 5-1
Chapter 5 describes the Modbus protocol.
5.1 Message Format ........................................................................................... 5-2
5.2 Function Code .............................................................................................. 5-3
5.3 Communication Mode ................................................................................... 5-3
5.4 Slave Responses .......................................................................................... 5-4
5.5 Calculating CRC-16 ...................................................................................... 5-5
5.6 Register Read and Write .............................................................................. 5-8
Read holding registers [03H] ........................................................................................... 5-8
Preset single register [06H] ............................................................................................ 5-10
Diagnostics (Loopback test) [08H] ................................................................................. 5-11
Preset multiple registers (Write multiple registers) [10H]............................................... 5-12
5.7 Caution for Handling Communication Data ................................................ 5-13
5.8 How to Use Modbus Data Mapping ............................................................ 5-15
5.9 How to Use Memory Area Data .................................................................. 5-18
5.9.1 Read and write of memory area data ............................................................................ 5-18
5.9.2 Control area transfer ..................................................................................................... 5-21