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 push_the_limits

link 4.09.2008 6:55 
Subject: changed bit or bits within a message
changed bit or bits within a message - измененного бита или битов в рамках сообщения??

1.2. ERROR DETECTION
There are two types of errors which may occur in a communications system: transmission errors and programming or operation errors.
The Modbus system has specific methods for dealing with either type of error. Communications errors usually consist of a changed bit or bits within a message. For example, 0001 0100 may become 0001 0110, changing the decimal value from 20 to 22. It is much less common to have a bit added to or deleted from a message. The most frequent cause of communications errors is noise: unwanted electrical signals in a communications channel. These signals occur because of electrical interference from machinery, damage to the communications channel, impulse noise (spikes), etc. Communications errors are detected by
character framing, a parity check, and a redundancy check.

заранее спасибо

 Lkovalskaya30

link 4.09.2008 7:18 
предлагает свои методы обработки указанных видов ошибки, / таких ошибок
м.б.

 Jespa

link 4.09.2008 8:15 
push_the_limits, имхо, Вы все правильно поняли. распространенная ошибка - изменение одного или нескольких битов в сообщении. такая ошибка как добавление в сообщение/удаление из сообщения битов встречается гораздо реже

 

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