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RS-485 interface polarity detecting method and system based on electric energy meter communication protocol

A RS-485, polarity detection technology, applied in the direction of measuring electricity, measuring devices, measuring electrical variables, etc., can solve the problems of easy reverse polarity, complicated polarity detection methods, etc., to achieve convenient construction and later maintenance, Realize the effect of simple and reliable, simple and reliable networking

Active Publication Date: 2013-09-25
BEIJING SMARTCHIP MICROELECTRONICS TECH COMPANY +3
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Solve the problem that the existing polarity detection method is too complicated and the polarity is easily reversed

Method used

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  • RS-485 interface polarity detecting method and system based on electric energy meter communication protocol
  • RS-485 interface polarity detecting method and system based on electric energy meter communication protocol
  • RS-485 interface polarity detecting method and system based on electric energy meter communication protocol

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Embodiment

[0061] Such as image 3 As shown, the polarity detection method flow process provided by the present invention is:

[0062] 1. When communicating through the RS-485 interface, according to the requirements of the multi-function electric energy meter protocol (DL / 645-1997), the leading byte 0xfe and the frame header 0x68 must be transmitted first, and then the address bits, data bits, etc. should be transmitted.

[0063] 2. If the leading byte 0xfe is used to judge, the probability of misjudgment is relatively high, so the frame header 0x68 is used to judge, that is, the differential signal between A and B received by the RS-485 receiver is stored in an 8-bit shift register. Judge the data in the register at the falling edge of the clock. If the data in the register is 0x68, it means that the polarity detection is correct; if the data in the register is 0x79, it means that the polarity detection is wrong; if the data in the register is not 0x68 or 0x97, It means that the data ...

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PUM

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Abstract

The invention relates to an RS-485 interface polarity detecting method and system based on an electric energy meter communication protocol. The method comprises the steps: (1) storing signals received by an RS-485 receiver in a register, (2) judging stored data, (3) switching a polarity switch, and (4) finishing the detection and starting to receive following data. The system comprises phase inverters, a receiver unit, a transmitter unit and a polarity detecting unit. The polarity detecting unit comprises a clock circuit, a polarity detecting circuit and the shifting register. A signal input pin of the transmitter unit is connected with one phase inverter. A signal input pin of the receiver unit is connected with the other phase inverter. When networking of an RS-485 module is performed, A and B polarities can be changed at random; a pull-up resistor and a pull-down resistor are only additionally arranged on a concentrator or a collector, and the networking is easy and reliable.

Description

technical field [0001] The invention relates to an electrical device, in particular to a polarity detection method and system based on the RS-485 interface of the electric energy meter communication protocol. Background technique [0002] In the power industry, the communication protocol for multi-function electric energy meters (DL / T645-1997) is generally used as the remote control communication protocol for electric meters. [0003] RS-485 is an interface standard that has the following features that make it the preferred serial interface standard: [0004] 1) RS-485 interface level is low, it is not easy to damage the chip of the interface circuit, and the level is compatible with TTL level, which can be easily connected with TTL circuit. [0005] 2) The maximum data transmission rate of the RS-485 interface is 10Mbps. [0006] 3) The maximum communication distance of the RS-485 interface is 4000 feet (about 1219 meters). [0007] 4) The RS-485 interface uses a combina...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/06
Inventor 胡鹏飞袁玉湘姜学平
Owner BEIJING SMARTCHIP MICROELECTRONICS TECH COMPANY
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