CN201297934Y

CN201297934Y - Intelligent transducer based on SPI protocol

Info

Publication number: CN201297934Y
Application number: CNU2008201875142U
Authority: CN
Inventors: 曹庆伟; 高亮; 付师杰
Original assignee: Xi'an Xianxing Measuring-Control System Co Ltd Zibo Branch
Current assignee: Xi'an Xianxing Measuring-Control System Co Ltd Zibo Branch
Priority date: 2008-08-08
Filing date: 2008-08-08
Publication date: 2009-08-26
Anticipated expiration: 2018-08-08

Abstract

The utility model belongs to the intelligent measurement field of pressure, temperature, flow, and the like, in particular relates to an intelligent transducer based on an SPI protocol, which comprises a sensor, a temperature measuring resistor thereof and a circuit mainboard and is characterized in that the circuit mainboard comprises a microprocessor, an AD signal converter and an SPI interface circuit; the sensor adopts a diffused-silicon pressure sensor powered by a high-power lithium battery of 3.6V, a shell made by an argon arc welding technology is arranged outside the sensor of the whole transducer, and the circuit mainboard is made by a special integrated circuit and a surface pasting technology and can be provided with a filter circuit and an ESD protective circuit. The low power consumption and double-output intelligent transducer based on the SPI protocol has the advantages of simple protocol, low hardware cost, battery supply, no power supply circuit, easy and convenient use and low cost and can be widely applied to the intelligent measurement of pressure, temperature, flow, and the like.

Description

Intelligent transducer based on the SPI agreement

Technical field

The utility model belongs to the intelligent measure field of pressure, temperature, flow etc., relates in particular to a kind of intelligent transducer.

Background technology

Traditional intelligent pressure transmitter adopts the structure of " pressure measuring element and temperature-measuring element; signal processing circuit; A/D Acquisition Circuit; microprocessor compensation adjustment and signal output apparatus " mostly, this structure often needs working pressure and two sensors of temperature, not only increased cost, and because the direct contact measurement medium of pressure measuring element, and temperature-measuring element adopts discrete device, and be placed on usually in the Transmitter Line plate, then can be because of the factor of device heating and heat radiation, the measured value of the temperature sensor that makes and medium temperature exist than big-difference, can not correctly reflect actual temperature, influence the compensation of back microprocessor; In addition, traditional intelligent transducer generally adopts industrial 24V electric power system, in some remote, remote occasions, the laying difficulty of supply line; In addition, many intelligent transducers adopt HART, industrial communication agreement and upper machine communications such as RS232, the shortcoming that exists agreement complexity, hardware cost to rise like this in some simple application scenarios, this just need provide a kind of low-power consumption powered battery, and can solve the novel intelligent transmitter of medium temperature measuring error effectively.On September 3rd, 2003, the Chinese patent 02257528.6 of bulletin disclosed a kind of intelligent temperature and humidity self compensation sensing transducer, it comprises the high-precision digital temperature sensor, anti-high humidity humicap, electric capacity/frequency-conversion circuit and measuring period generative circuit, single-chip microcomputer, eeprom memory, RS485 network communication interface circuit and width modulation (PWM) and voltage transitions driving circuit, this its agreement complexity of intelligent temperature and humidity self compensation sensing transducer, hardware cost is higher, and non-powered battery, need to lay supply line, also can't realize the dual output of temperature and pressure measured value, it uses complicated, the cost height.

Summary of the invention

The purpose of this utility model is to overcome above defective, a kind of intelligent transducer based on SPI (Serial Peripheral Interface) agreement is provided, this intelligent transducer based on the SPI agreement uses advanced super low-power consumption design, powered battery, need not to lay supply line, adopt sensor measuring media temperature simultaneously, pressure signal, by the automatic zero adjustment technology, linear technology of software and technique for temperature compensation, adopt the outside communication modes that wakes up, use the SPI communications protocol to realize instruction output temperature simultaneously, two signals of force value have promptly been simplified communications protocol, further reduce the transmitter power consumption again, and has the measuring accuracy height, agreement is simple, and hardware cost is low, powered battery, need not to lay supply line number, advantage easy to use.

The technical scheme that the utility model adopted is as follows:

A kind of intelligent transducer based on the SPI agreement comprises sensor and coupled temperature measuring resistors, and the circuit mainboard is characterized in that: the circuit mainboard comprises microprocessor, AD signal converter and SPI interface circuit.

Described intelligent transducer based on the SPI agreement, sensor adopts the diffusion silicon pressure sensor of 3.6V high power lithium battery power supply.

Described intelligent transducer based on the SPI agreement, sensor outside or whole transmitter outside are provided with the housing that inferior arc welding technology is made.

Described intelligent transducer based on the SPI agreement, circuit mainboard adopt special IC and surperficial sealing technology to make.

Described intelligent transducer based on the SPI agreement, the circuit mainboard can be provided with filtering circuit.

Described intelligent transducer based on the SPI agreement, the circuit mainboard can be provided with esd protection circuit.

Described intelligent transducer based on the SPI agreement, the housing of sensor or whole transmitter outside adopts stainless steel material.

So in use, sensor adopts the constant voltage power supply mode, utilize its bridge to press good temperature characterisitic, temperature detecting resistance voltage swing and measuring media are linear when temperature variation, special algorithm through microprocessor compensates the caused pressure output error of bridge pressure variation again, obtain the precise dose value, gather the bridge pressure variation that pressure causes simultaneously, obtain the pressure output voltage, after the temperature compensation processing, the outputting standard force value by above scheme, has realized a sensor output pressure and temperature signal simultaneously; Microprocessor carries out the linear compensation correction to the temperature, pressure signal of gathering, utilize the temperature signal of gathering that the temperature of sensor is floated automatic compensation again, can effectively improve sensor accuracy, the data of all corrections are kept among the EEPROM (EEPROM (Electrically Erasable Programmable Read Only Memo)) of microprocessor, the correction factor that permanent storage computation is come out, and the influence of not cut off the power supply; To be processed into the data hardwood form of standard through the two paths of signals of above-mentioned steps collection; By the mode of host wake-up, adopt the SPI communication modes, send data to main frame, adopt this data, guaranteed real time of data acquisition, the empty stand-by period when having reduced no signal, thus further reduced power consumption; Sensor adopts the power supply of 3.6V high power lithium battery; Utilize microprocessor clock circuit flexibly, the system idle condition of making is in the super low-power consumption pattern, under the duty, improves processor clock frequency, improves conversion speed, reduces the processing time; In addition; filtering circuit can be got rid of by being electromagnetically coupled to the undesired signal in the system; ESD (static discharge) holding circuit can prevent to destroy the plate circuit because of electrostatic induction; the excellent protection circuit provides prerequisite for transmitter reliable and stable work under rugged surroundings; its sensor, transmitter housing adopt inferior arc welding technology, waterproof effectively.

Intelligent transducer based on the SPI agreement of the present utility model adopts the super low-power consumption design, the bridge resistance temperature characterisitic of utilizing sensor itself is by software compensation algorithm measurement medium temperature, by the automatic zero adjustment technology, software is linear, temperature compensation effectively improves the transmitter precision, in addition, it adopts outside awakening technology further to reduce power consumption, and use SPI communications protocol and host computer interface, realize that an instruction reads temperature, the purpose of the dual output of force value has been simplified communications protocol greatly, it is simple to have agreement, auto thermal compensation, automatic zero adjustment, measuring accuracy and measurement accuracy height, antijamming capability is strong, hardware cost is low, and powered battery need not to lay supply line, easy to use, cost is low, and the advantage of long working life can be widely used in pressure, temperature, the intelligent measure of flow etc.

Description of drawings

Fig. 1 is based on the intelligent transducer sensor construction figure of SPI agreement;

Fig. 2 is based on the intelligent transducer work main program flow chart of SPI agreement;

Fig. 3 is based on the intelligent transducer work interruption main program flow chart of SPI agreement;

Fig. 4 is based on the intelligent transducer communication sequential chart of SPI agreement;

Fig. 5 is based on the intelligent transducer temperature-measurement principle communications protocol synoptic diagram of SPI agreement;

Fig. 6 is based on the intelligent transducer temperature-measurement principle sequential chart of SPI agreement;

Fig. 7 is based on the intelligent transducer temperature-measurement principle process flow diagram of SPI agreement.

Wherein, 1 pressure ring, 2 diaphragms, 3 silicons, 4 plastic lining seats, 5 sensor base, 6 plastics pilot mouths, 7 thick film ceramic compensating circuits, 8 conductive strips.

Embodiment

The utility model is described in further detail below in conjunction with drawings and embodiments:

Extremely shown in Figure 7 as Fig. 1; a kind of intelligent transducer based on the SPI agreement; comprise sensor and temperature measuring resistors thereof and circuit mainboard; its circuit mainboard comprises microprocessor; AD (analog/digital) signal converter and SPI interface circuit; sensor adopts the diffusion silicon pressure sensor of 3.6V high power lithium battery power supply; the circuit mainboard adopts special IC and surperficial sealing technology to make; the circuit mainboard is provided with filtering circuit and esd protection circuit; the outside is provided with the Stainless Steel Shell that inferior arc welding technology is made, and wherein sensor is by pressure ring 1; diaphragm 2; silicon 3; plastic lining seat 4; sensor base 5; plastics pilot mouth 6; thick film ceramic compensating circuit 7 and conductive strips 8 are formed.

Like this when work, as the sensor of front end sensitive element, the effect that the diaphragm on it is measured pressure medium produces deformation, gives the sensor internal silicon with pressure signal transmission, be converted into the mV signal simultaneously, the size of mV value becomes linear dependence with the size of pressure; In the circuit,, thereby obtain a temperature dependent voltage in resistance R of electric bridge low-pressure side series connection, increase this resistance and can reduce bridge voltage, thereby reduce its output, the amplitude that reduces is generally little, and only needing to increase gain slightly or reduce reference voltage just is enough to it is compensated; When temperature rises, the rising of bridge resistor is also risen the voltage drop on the electric bridge, this bridge voltage has formed an additional bridge with variation of temperature and has pressed the temperature coefficient item, and this be worth on the occasion of, and the intrinsic TCS value (sensitivity temperature coefficient of sensor) of sensor is a negative, the TCS error that a resistance is connected with sensor and in fact promptly reduced not compensated like this, and top collimation technique is still effective, just need the error of compensation more smaller; Then by multi-way switch time sharing sampling temperature, pressure signal, analog passband signal is converted into digital quantity by 16 high-precision adcs (analog to digital converter), by the linear compensation deals of inside after crossing the programmable amplifier amplification, temperature compensation is handled, the temperature, pressure signal of range conversion outputting standard; Filtering circuit can be got rid of by being electromagnetically coupled to the undesired signal in the system, and esd protection circuit can prevent to destroy the plate circuit because of electrostatic induction; Sensor, transmitter housing adopt inferior arc welding technology, waterproof effectively.

Because adopt the super low-power consumption design, most of times of little processing are in sleep pattern, utilize the interrupt-driven system flow process, sensor carries out self diagnosis one time at set intervals, and the gained parameter is stored among the EEROM automatically, transfers electricity back parameter unaffected.Externally under the trigger pip, system wake-up, the sampling processing data, the data hardwood of generation specific data form is provided with end mark after finishing dealing with, externally pulse signal transmits data down, therefore greatly reduce the power consumption of total system, effectively prolonged the service time of battery, this transmitter adopts the mode of operation of Remote Wake Up, the needs of host computer sampling can either be well solved, power consumption can be reduced again.

Claims

1, a kind of intelligent transducer based on the SPI agreement comprises sensor and coupled temperature measuring resistors, and the circuit mainboard is characterized in that: the circuit mainboard comprises microprocessor, AD signal converter and SPI interface circuit.

2, the intelligent transducer based on the SPI agreement according to claim 1 is characterized in that: sensor adopts the diffusion silicon pressure sensor of 3.6V high power lithium battery power supply.

3, the intelligent transducer based on the SPI agreement according to claim 1 is characterized in that: sensor or whole transmitter outside are provided with the housing that inferior arc welding technology is made.

4, the intelligent transducer based on the SPI agreement according to claim 1 is characterized in that: the circuit mainboard adopts special IC and surperficial sealing technology to make.

5, the intelligent transducer based on the SPI agreement according to claim 1, it is characterized in that: the circuit mainboard is provided with filtering circuit.

6, the intelligent transducer based on the SPI agreement according to claim 1, it is characterized in that: the circuit mainboard is provided with esd protection circuit.