Industrielle styresystemer - Wiki
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To send and receive data on Master side we need to use 2 channels:
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- TO RECEIVE DATA - Read Input Registers (Function Code
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- 04)
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- TO SEND DATA - Write Multiple Registers (Function Code
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- 16)
Step 1. Modbus Slave Channel - Add channel - FC
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04 - Length 10
To send get or write read data we need to use channel 0 with access type Write Multiple Read Input Registers (Function Code 1604).
Since we have decided to use approximately 8 variables, the length will be set to 10 (this value can be changed).
Step 2. Modbus Slave Channel - Add channel - FC
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16 - Length 10
To receive sent or read write data we need to use channel 1 with access type Read Holding Write Multiple Registers (Function Code 0316).
Since we have decided to use approximately 8 variables, the length will be set to 10 (this value can be changed).
NB! We need to change Offset from 0011, because of values from 0 to 10 are allready assigned to Channel 0.
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NB!
As a result:
Step3. ModbusTCP Slave I/O Mapping
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- Enabled 2 (always in bus cycle task)
Step4. In this step we need to define our variables.
NB! The register 0 we have for BOOL variables.
En example for Reading registers - INPUT
En example for Writing registers - OUTPUT
Now we need to map the server/slave side
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