| 主权项 |
1. A bus coupler for coupling field devices to a superordinate bus system, comprising:
a connection for the superordinate bus system; a respective connection being provided for each respective field device of a plurality of field devices; a main transmit-receive unit configured to transmit and receive telegrams on the superordinate bus system; a respective transmit-receive unit configured to communicate with each respective field device of the plurality of field devices; wherein each respective transmit-receive unit includes:
a signal input for telegrams of the superordinate bus system, which is connected to the main transmit-receive unit,a field device output for connection of the field devices, via which the telegrams are sent from the main transmit-receive unit to the field devices,a receive signal connection, via which the telegrams are forwarded from the plurality of field devices to the main transmit-receive unit, anda control input, each respective transmit-receive unit being configured such that the signal input is connected to a first input of an impedance converter, a second input of the impedance converter is connected to a controllable reference means, an output of the impedance converter is connected to a terminating resistor in a series circuit at the field device output, and a measuring means for determining a voltage drop is connected to the terminating resistor and the measuring means is connected to the reference means. |
