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Modbus/en: различия между версиями
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(Новая страница: «=== Modbus request and response data format ===») |
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The function is encoded in one byte and determines what action the server device should perform. Function codes range from 1 to 255, with codes 128 to 255 reserved for error messages from the server device. Code 0 is not used. The size of the data block can vary from zero to the maximum allowed. If the request is processed correctly, the server device returns an ADU containing the requested data. | The function is encoded in one byte and determines what action the server device should perform. Function codes range from 1 to 255, with codes 128 to 255 reserved for error messages from the server device. Code 0 is not used. The size of the data block can vary from zero to the maximum allowed. If the request is processed correctly, the server device returns an ADU containing the requested data. | ||
[[ | [[File:Modbus_transaction_OK.png|700px|thumb|center|Modbus-transaction without errors]] | ||
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