发明名称 |
COLLISION DETECTION IN EIA-485 BUS SYSTEMS |
摘要 |
A communication module is disclosed for Intelligent Electronic Devices (IEDs) which can implement the EIA-485 standard, including an intelligent hardware support that can allow a known software-based collision detection function to detect collisions independently of the location of the message sources on the transmission line. The hardware support can enable both a “strong signal driving” mode as well as a “weak signal driving” mode. In the weak mode, a biasing, or attenuating, or voltage-dividing resistor can be temporarily inserted between a transmitter, or voltage source, and the transmission line. |
申请公布号 |
US2014372645(A1) |
申请公布日期 |
2014.12.18 |
申请号 |
US201414477369 |
申请日期 |
2014.09.04 |
申请人 |
ABB Technology AG |
发明人 |
HECKROTT Cornelius;PIND Henrik |
分类号 |
G06F13/42 |
主分类号 |
G06F13/42 |
代理机构 |
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代理人 |
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主权项 |
1. A method of facilitating message collision detection in a communication bus system operating according to EIA-485, wherein a signal transmitter is connected to a transmission line for transmitting a binary signal including a first bit followed by a second bit, the method comprising:
applying a first voltage indicative of the first bit to the transmission line; applying, during a transitional period shorter than a duration of the second bit, a second voltage indicative of the second bit to the transmission line; applying, during a weak driving period following the transitional period, a third voltage indicative of the second bit to the transmission line via a biasing resistor; and detecting a superposition of the third voltage with a signal from an interfering message source connected to the transmission line, by a receiver connected to the transmission line. |
地址 |
Zurich CH |