How Can You Connect Or Disconnect A Fieldbus Instrument From The Bus Without Affecting The Performance Of The Rest Of The Instruments? What Sort Of Disturbance Is Introduced During Addition Or Disconnection Of An Instrument? How Can It Be Detected?
IEC61158-2 specifies that connecting or disconnecting a device may disturb the bus electrically for not more than 10ms. That means that one message might be corrupted. Each message includes a 16-bit error-check-polynomial code, which virtually guarantees detection of the corruption by the receiver.
Depending on the type and use of the message, the receiver might ask for a repeat, or might simply ignore the message and wait for it next time around. Where the sender needs to know about this, an “acknowledged” message type can be used, and the receiver would simply not acknowledge the lost message.