| 主权项 |
1. A method for digital communication between at least one first node being a master node or a node in a master mode and a plurality of second nodes respectively being a slave node or a node in a slave mode and which are connected with the first node by a serial field bus supporting different physical field bus levels comprising a dominant physical field bus level and a recessive physical field bus level for representing logical values comprising logical ones and logical zeroes of bits making up digital messages which are sent via the field bus,
A1) wherein a respective node, for sending a digital message via said field bus to at least one other node, time-dependently manipulates the field bus, so that time-dependently assumed physical field bus levels represent the bits of said digital message, wherein at least the second nodes manipulate the field bus by bitwise setting or not setting the physical field bus level from the recessive physical field bus level to the dominant physical field bus level, A2) wherein the nodes, for reading digital messages sent via said field bus, detect time-dependently assumed physical field bus levels to read bits of a respective message, A3) wherein the second nodes are adapted to respond to predetermined digital messages read by sending a respective response message, wherein the method provides a first mode of digital communication between said nodes via said field bus with the following features and method steps: B1) the first node sends a predetermined digital broadcast polling message of first type, B2) a plurality of the second nodes is adapted to respond to the digital broadcast polling message of first type in synchronism by simultaneously sending a respective predetermined digital response message of first type, B3) the digital response messages of first type comprise at least one data word of predetermined bit length and each second node has associated at least one particular of the bits of said data word, so that each bit is associated to only one particular of said second nodes, and B4) the second nodes are adapted to send their respective response messages of first type to the first node by manipulating said physical field bus level with respect to said data word only for said at least one bit associated to the respective second node but not to manipulate said physical field bus level for bits of said data word associated to other second nodes,
so that the first node reads one resulting digital response message of first type comprising a resulting data word of said predetermined bit length, wherein the bits of said resulting data word for which the respective logical value is represented by the dominant physical field bus level identify all second nodes having responded to the digital broadcast polling message of first type by setting the physical field bus level to the dominant physical field bus level with respect to said at least one bit associated to the respective second node and wherein for any second node not having read the digital broadcast polling message of first type or not being operational to communicate the logical value of the respective associated at least one bit is represented by the recessive physical field bus level, characterized in that: C1) the second nodes are adapted to assume at least a first and a second operational state, wherein a second node assuming the first operational state and having read the digital broadcast polling message of first type sets its associated at least one bit to the dominant physical field bus level, to indicate its assuming of the first operational state to the first node, C2) a second node assuming the second operational state and having read the digital broadcast polling message of first type refrains from setting its associated at least one bit to the dominant physical field bus level, to indicate its assuming of the second operational state to the first node, C3) the first node is adapted to react to a resulting digital response message having a resulting data word of which at least one bit assumes the recessive physical field bus level according to a predetermined reaction schedule, which involves at least one of i) sending at least one predetermined further digital message via the field bus or sending at least one trigger signal by manipulating the field bus in a predetermined manner and ii) monitoring the field bus for digital information messages sent by second nodes assuming the second operational state. |
