CN202305788U

CN202305788U - Test device of loading capability and communication distance of 485 communication circuit of intelligent electric energy meter

Info

Publication number: CN202305788U
Application number: CN2011204255228U
Authority: CN
Inventors: 武新旗; 杨西霞; 孙世杰; 刘志亮; 李开; 关凤霞; 刘岩
Original assignee: SHENZHEN JIANGJI INDUSTRY Co Ltd
Current assignee: SHENZHEN JIANGJI INDUSTRY Co Ltd
Priority date: 2011-11-01
Filing date: 2011-11-01
Publication date: 2012-07-04
Anticipated expiration: 2021-11-01

Abstract

The utility model relates to a test device of loading capability and communication distance of a 485 communication circuit of an intelligent electric energy meter, which is characterized by comprising a single chip microcomputer circuit connected with a 485 communication circuit. The 485 communication circuit is connected with a resistance analog circuit. The single chip microcomputer circuit comprises a single chip microcomputer U1 in 78F9222 type. The 485 communication circuit comprises a chip U15 in MAX 3085 chip, a resistor R21, a resistor R26, a resistor R29, a resistor R33, a resistor R34, a resistor R36, a resistor R37, a resistor R85, an optical coupler OP1 and an optical coupler OP2, a triode Q3 and a capacitor C14 are connected. The resistance analog circuit comprises an adjustable resistor R1, an adjustable resistor R2, an adjustable R3, a switch S1, a switch S2 and a switch S3 which are connected with an A interface and a B interface of the 485 communication circuit. The test device can test the loading capability and the communication distance of the 485 communication circuit through resistance analog load and an analog communication wire resistor and provides evidences for optimization of circuit design and improvement of reliability of the 485 communication circuit.

Description

Intelligent electric energy meter 485 communicating circuit load capacities and communication distance proving installation

Technical field

The utility model relates to proving installation, more particularly, is a kind of intelligent electric energy meter 485 communicating circuit load capacities and communication distance proving installation.

Background technology

The develop rapidly of Along with computer technology, network technology, sensor technology is in the applied more and more of China's Urban House sub-district intellectualized technology.The intellectuality of residential quarters generally includes building talkback, gate inhibition, remote meter reading, security alarm, broadband etc., and wherein long-distance meter-reading system is because it is convenient and swift, accurate, the trouble and the leakage of checking meter of being convenient to have added up, avoided to register one's residence copied, estimate and phenomenon such as copy and more and more come into one's own.Remote meter reading mainly is divided into two types, one type of kilowatt meter reading-out system that is based on power line carrier, its advantage be connect up less, cost is low; But because signal and forceful electric power transmit on single line, have the interference of highfield in the transmission course inevitably, the reliability of signal is affected, and along with the increase of transmission range, the decay of signal is very fast, has influenced the reliability of meter reading data; The another kind of kilowatt meter reading-out system that is based on RS-485, this system is comparatively desirable a kind of long-distance meter-reading system, and along with user's quick increase, the load meeting of 485 communicating circuits increases, and communication distance is also at continuous lengthening, and signal also can be decayed thereupon.How to guarantee 485 communicating circuits load increase and the situation of distance lengthening under, remote meter reading can also normally copy reading data oneself become the technical barrier of this area.

Summary of the invention

The purpose of the utility model provides a kind of intelligent electric energy meter 485 communicating circuit load capacities and communication distance proving installation; Test 485 communicating circuit load capacities and communication distance ability with resistance fictitious load, analogue communication conductor resistance; For optimizing circuit design, the reliability that improves 485 communicating circuits provides foundation.

The purpose of the utility model is realized by following technical scheme: a kind of intelligent electric energy meter 485 communicating circuit load capacities and communication distance proving installation; It is characterized in that: it comprises that single chip circuit is connected with 485 communicating circuits; 485 communicating circuits are connected with the resistance simulation circuit, and described single chip circuit comprises that model is 78F9222 single-chip microcomputer U1; Said 485 communicating circuits comprise model MAX3085 chip U15, resistance R 21, R26, R29, R33, R34, R36, R37, R85, and optocoupler OP1, OP2, triode Q3 is connected with capacitor C 14; Described resistance simulation circuit comprises that adjustable resistance R1, R2, R3 and switch S 1, S2, S3 are connected with 485 telecommunication circuit A, B interface.

The intelligent electric energy meter 485 communicating circuit load capacities of the utility model and the beneficial effect of communication distance proving installation are embodied in: can test 485 communicating circuit load capacities and communication distance ability with resistance fictitious load, analogue communication conductor resistance; For optimizing circuit design, the reliability that improves 485 communicating circuits provides foundation.

Description of drawings

Fig. 1 is intelligent electric energy meter 485 communicating circuit load capacities and communication distance proving installation schematic block circuit diagram.

Fig. 2 is power-supplying circuit 1 schematic diagram among Fig. 1.

Fig. 3 is single chip circuit 2 schematic diagrams among Fig. 1.

Fig. 4 is 485 communicating circuits 3 and resistance simulation circuit 4 schematic diagrams among Fig. 1.

Embodiment

With reference to Fig. 1; The intelligent electric energy meter 485 communicating circuit load capacities and the communication distance proving installation of the utility model comprises that single chip circuit 2 is connected with 485 communicating circuits 3; 485 communicating circuits 3 are connected with resistance simulation circuit 4, are that 78F9222 single-chip microcomputer U1 and 485 communicating circuits 3 provide 5V stabilized voltage supply by power-supplying circuit 1 for single chip circuit 2 models.

With reference to Fig. 2, power-supplying circuit 1 is prior art power circuit commonly used, and the transformer TR2 front end of power-supplying circuit 1 is with doing over-voltage over-current protection in the thermistor FHPTC1 series circuit He in the voltage dependent resistor (VDR) YM parallel circuit; Transformer TR2 has two-way output, and the rectifier bridge that the first via adopts 2 commutator tube D3, D4 to form becomes alternating voltage into DC voltage; Direct current crimping model is the voltage stabilizing chip U8 of 78L05; The 5V power supply that voltage stabilizing chip U8 output is stable, electric capacity DC10, DC7, DC3, DC4 ground connection are played the effect of filtering, the rectification circuit that second terminal adopts diode D6 to form; Alternating voltage is become DC voltage; Direct current crimping model is the voltage stabilizing chip U5 of 78L05, and model is the stable 5V power supply of voltage stabilizing chip U5 output of 78L05, and electric capacity DC25, DC27, DC30, DC29 ground connection are played filter action.

With reference to Fig. 3; Described single chip circuit 2 comprises that model is 78F9222 single-chip microcomputer U1; The external 5MHz crystal oscillator of 2, the 3 pin XT2 of single-chip microcomputer U1 provides necessary clock frequency for single-chip microcomputer U1; Single-chip microcomputer U1 is 8 single-chip microcomputers, and its main resource is following: 4Kflash, 256 byte RAM, 17 I/O mouths, 9 external interrupt mouths, 4 tunnel 10 AD, 1 asynchronous serial port UART, 48 bit timing devices, WatchDog Timer, low-voltages detect the LVD reset function.

With reference to Fig. 4, described 485 communicating circuits 3 comprise model MAX3085 chip U15, resistance R 21, R26, R29, R33, R34, R36, R37, R85, and optocoupler OP1, optocoupler OP2, triode Q3 is connected with capacitor C 14; Described resistance simulation circuit comprises that adjustable resistance R1, R2, R3 and switch S 1, S2, S3 are connected with 485 communication A, B interface.485 communicating circuits 3 adopt model MAX3085 chip U15; When 220V civil power that communication line imports because of unexpected breakage or human damage can be effectively prevented in the use that in design, has increased thermistor PTC3, PTC4 and TVS pipe to the damage of this interface, in the time of also can suitably reducing the lightning induction communication to the influence of this interface.Model MAX3085 chip U15 is to adopt the I2C bus mode to be connected with model 78F9222 single-chip microcomputer U1; Through optocoupler OP1, optocoupler OP2 and model 78F9222 single-chip microcomputer 12; 13 pin connect, and the signal 485TXD control that the transmitting-receiving of model MAX3085 chip U15 is sent by model 78F9222 single-chip microcomputer U1 is through the triode Q3 of model 9015; The state of control model MAX3085

chip

2,3 pin is realized the transmitting-receiving of model MAX3085 chip U15.Described resistance simulation circuit 4 is connected and forms with 485 telecommunication circuit A, B interface by adjustable resistance R1, R2, R3 and switch S 1, S2, S3.Value through regulating adjustable resistance R1, R2 is tested 485 maximum communication distances, regulates the load capacity that adjustable resistance R3 tests 485 communications.Switch S 1, S2, S3 are whether places in circuit of control adjustable resistance R1, R2, R3.During test communications length, switch S 1, S2, S3 short dot break off, and with adjustable resistance R1 and R2 place in circuit, adjustable resistance R3 breaks off, and regulates adjustable resistance R1, R2, and test 485 communications, observe the minimum resistance under the stabilized communication situation; During the calibration tape loading capability, connect switch S 1, S2, S3, adjustable resistance R1, R2 are broken off, adjustable resistance R3 place in circuit is regulated adjustable resistance R3, observes the maximum resistance under the stabilized communication situation.

Claims

1. intelligent electric energy meter 485 communicating circuit load capacities and communication distance proving installation; It is characterized in that: it comprises that single chip circuit is connected with 485 communicating circuits; 485 communicating circuits are connected with the resistance simulation circuit, and described single chip circuit comprises that model is 78F9222 single-chip microcomputer (U1); Said 485 communicating circuits comprise model MAX3085 chip (U15), resistance (R21, R26, R29, R33, R34, R36, R37, R85), and optocoupler (OP1, OP2), triode (Q3) is connected with electric capacity (C14); Described resistance simulation circuit comprises that adjustable resistance (R1, R2, R3) is connected with 485 telecommunication circuit A, B interface with switch (S1, S2, S3).