Кибернетика, автоматика, протоколы

вот с оригинала Modicon Modbus Protocol Reference Guide PI–MBUS–300 Rev. J June 1996 MODICON, Inc., Industrial Automation Systems One High Street North Andover, Massachusetts 01845 The entire message frame must be transmitted as a continuous stream. If a silent interval of more than 1.5 character times occurs before completion of the frame, the receiving device flushes the incomplete message and assumes that the next byte will be the address field of a new message. Similarly, if a new message begins earlier than 3.5 character times following a previous message, the receiving device will consider it a continuation of the previous message. This will set an error, as the value in the final CRC field will not be valid for the combined messages. A typical message frame is shown below.