| 摘要 |
A field bus control system uses electronic units having a high impedance which appear as constant current consumers except for any particular unit during transmission which creates a signal by a varying current consumption causing detectable and hence demodulable voltage variations at the other units. Due to the invention safety is obtained in a very simple manner against errors and accidents cause by 1) common mode interference in the bus cable, 2) incorrect termination impedance of the bus cable at connected units, 3) discharge of capacitive energy from the individual units in case of short circuit of the system, and 4) discharge of energy stored in the self-inductance in sections of the cable in case of breakage in order to avoid discharges causing fires.
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