CN206684225U

CN206684225U - A kind of digital conductivity sensor

Info

Publication number: CN206684225U
Application number: CN201720328871.5U
Authority: CN
Inventors: 杨洋
Original assignee: Nanjing Qijue Electronic Technology Co Ltd
Current assignee: Nanjing Qijue Electronic Technology Co Ltd
Priority date: 2017-03-31
Filing date: 2017-03-31
Publication date: 2017-11-28
Anticipated expiration: 2027-03-31

Abstract

The utility model discloses a kind of digital conductivity sensor, including front end electrode tip, front end electrode tip is connected by data wire with data signal joint, and a digital signal processing device is packaged with the top of the electrode tip of front end or on the data wire of annex；Digital signal processing device includes power interface and communication interface module, single-chip microcomputer, power isolation module, AC signal DDS module and measurement module；AC signal DDS module and measurement module are connected with front end electrode tip respectively, single-chip microcomputer is connected with power interface and communication interface module, AC signal DDS module and measurement module respectively, measuring control signal is exported to AC signal DDS module, measurement signals are obtained from measurement module.Compared with prior art, the utility model provides a kind of miniaturization, implicit type and intelligentized digital electrode, has the advantages that to be not easy to polarize, anti-interference, convenience is high, cost-effective and space.

Description

A kind of digital conductivity sensor

Technical field

A kind of digital conductivity sensor is the utility model is related to, belongs to sensor technical field.

Background technology

The structure of conductivity value measurement apparatus common at present is made up of instrument and simulation conductivity electrode two parts, instrument Table is divided into display liquid crystal display, data acquisition and the bulk of data transfer three again.The front end analogue electrical conductivity of existing conductivity sensor Electrode tip, it is connected by data lead with needle-like joint or other joints, carries out the transmission of analog data signal.Prior art is deposited The problem of：1st, analog conductivity sensor, to send data to computer must first connect instrument or transmitter, cause Cost increase, installation is inconvenient, space hold.2nd, analog conductivity sensor uses ac-excited, and AC signal is small, pole It easily by external interference, such as motor-field interference, static electricity on human body's interference, causes data unstable, data error is big.3rd, it is analog Conductivity sensor needs special coaxial shielding line to be extended, and is brought inconvenience to use.4th, analog conductivity sensor It must be calibrated when using first, need again to recalibrate electrode after changing instrument or transmitter, used In cumbersome.

Utility model content

Goal of the invention：The problem of existing for prior art, the utility model purpose are to provide a kind of digital electrical conductivity Sensor, by the integrated digital processing module in electrode interior or close electrode output cord, external interference is prevented, and improve Conductivity sensor property easy to use, realizes the miniaturization of digital conductivity sensor, implicit type and intellectuality.

Technical scheme：To achieve the above object, the utility model adopts the following technical scheme that：

A kind of digital conductivity sensor, including front end electrode tip, front end electrode tip are connect by data wire and data signal Head connection, is packaged with a digital signal processing device at the top of the electrode tip of front end or on the data wire of front end electrode tip annex Put；Digital signal processing device includes power interface and communication interface module, single-chip microcomputer, power isolation module, AC signal DDS Module and measurement module；AC signal DDS module and measurement module are connected with front end electrode tip respectively, single-chip microcomputer respectively with power supply Interface connects with communication interface module, AC signal DDS module with measurement module, output measuring control signal to AC signal DDS module, measurement signals are obtained from measurement module；Power isolation module is located at power interface and AC signal DDS module Between.

Preferably, temperature sensor is additionally provided with the electrode tip of front end, in temperature sensor and digital signal processing device Measurement module connection.

Preferably, power interface and communication interface module are based on RS485, RS232 or UART communications protocol and outside is set Standby communication, is powered by external equipment.

Preferably, digital signal processing device also includes voltage transformation module, for 5V voltage conversions is electric into 3.3V Pressure.

Preferably, front end electrode tip uses the stainless steel electrode with temperature compensation.

Beneficial effect：Compared with prior art, the utility model has the following advantages that：1. it is not easy to polarize.Make it in high electricity Also do not polarized under the solution of conductance.It is 2. anti-interference.Digital signal processing device is integrated into electrode interior or exported close to electrode On cable, it is therefore prevented that external interference.3. convenience is high.Digital conductivity sensor directly exports the mark such as RS485, RS232, UART Accurate data signal, it is convenient to dock PC ends and mobile terminal.It is 4. cost-effective.User, which obtains conductivity measurement data, no longer to be needed to purchase Buy instrument or transmitter.5. save space.Instrument or transmitter space-consuming are eliminated, is easily installed.

Brief description of the drawings

Fig. 1 is the structural representation of the utility model embodiment.

Fig. 2 is the schematic block circuit diagram of the utility model embodiment.

Fig. 3 is the control flow chart of the utility model embodiment.

Embodiment

With reference to specific embodiment, the utility model is furtherd elucidate, it should be understood that these embodiments are merely to illustrate this Utility model rather than limitation the scope of the utility model, after the utility model has been read, those skilled in the art couple The modification of the various equivalent form of values of the present utility model falls within the application appended claims limited range.

As shown in Figure 1, 2, a kind of digital conductivity sensor disclosed in the utility model embodiment, including front end electrode tip 1, front end electrode tip 1 is connected by data wire 3 with data signal joint 4, in front end at the top of electrode tip 1 or apart from front end electrode tip A digital signal processing device 2 is packaged with data wire 3 at 1 output end 12-18cm, to the analog signal of electrode tip output Handled and changed, export such as RS485, RS232, UART standard data signal, so as to directly with PC ends or mobile terminal Docking.Digital signal processing device 2 is sealed in data cable by epoxy encapsulating integrated molding technology, and classification of waterproof reaches IP68.Wherein, digital signal processing device 2 includes power interface and communication interface module, single-chip microcomputer, power isolation module, friendship Flow signal DDS module and measurement module；AC signal DDS module and measurement module are connected with front end electrode tip respectively, single-chip microcomputer It is connected respectively with power interface and communication interface module, AC signal DDS module and measurement module, output measuring control signal is extremely AC signal DDS module, measurement signals are obtained from measurement module；Power isolation module is located at power interface and AC signal Between DDS module.In order to need the environment of temperature-compensating suitable for some, temperature sensor or straight is additionally provided with the electrode tip of front end Connect using the stainless steel electrode with temperature compensation.

Describe the specific structure of the utility model and device in detail so that communication interface uses RS485 communications protocol as an example below Type selecting.

1. interface section：Interface section is made up of power interface and communication interface, power interface low voltage difference integrated chip LDO (such as AMS1117) changes into 3.3V and powered to single-chip microcomputer, and LDO chips can be saved if single-chip microcomputer supply voltage is 5V.Communication connects Oral area point realizes the RS-485MODBUS-RTU slave communicaton protocols of standard, for PC ends or mobile device communication, use RS485 special chips (such as MAX485).

2. single-chip microcomputer：Single-chip microcomputer is the system master of digital sensor, completes reading and processing to conductivity electrode, real Now docked with upper layer software (applications).The single-chip microcomputer of communication interface of the selection with standard, with (SPI, I2C, UART), should have low Power consumption characteristics, such as ST STM32F0 series.

3. power isolation module：In order to improve system accuracy and security, analog circuit should with power supply unit power supply every From improving the anti-interference and accuracy of data.The isolation module (such as TI DCP series) of micro energy lose is selected, 5V turns 5V isolation electricity Press 1000V.

4. AC signal DDS module：The ac-excited AD9850DDS chips using ADI companies, and high accuracy 16 And above ADC (such as TI ADS 1120), with the interface such as SPI and reference voltage.

5. measurement module：Using high-precision adc chip, processing is acquired to electrode front end.Sensor signal is usually Faint voltage or current signal, Gain tuning can be carried out to improve precision and signal condition with the PGA of ADC pieces.

6. conductivity electrode：Using the stainless steel electrode with temperature compensation.

For a specific digital conductivity sensor, communication interface chip uses MAX485 chips, and power interface uses AMDS1117, the chip carry 3.3 output voltages, give single-chip microcomputer SMT32F030 power supply, isolating chip using DC100505 every From ADC uses ADS1120.Temperature sensor uses NTC10K.Scm software uses ARM MDK platforms.After start, monolithic Machine is initialized, and host computer is transmitted to single-chip microcomputer by MAX485 chips, after single-chip microcomputer receives instruction, will handle the electricity of completion Number of poles realizes measurement and communication according to host computer is uploaded to.

Claims

1. a kind of digital conductivity sensor, it is characterised in that including front end electrode tip, the front end electrode tip passes through data wire It is connected with data signal joint, is packaged with the top of the front end electrode tip or on the data wire near the front end electrode tip One digital signal processing device；The digital signal processing device includes power interface and communication interface module, monolithic are mechanical, electrical Source isolation module, AC signal DDS module and measurement module；The AC signal DDS module and measurement module respectively with front end Electrode tip connects, and the single-chip microcomputer connects with power interface and communication interface module, AC signal DDS module and measurement module respectively Connect, output measuring control signal to AC signal DDS module, measurement signals are obtained from measurement module；The isolated from power Module is between power interface and AC signal DDS module.

2. a kind of digital conductivity sensor according to claim 1, it is characterised in that also set in the front end electrode tip There is temperature sensor, the temperature sensor is connected with the measurement module in digital signal processing device.

3. a kind of digital conductivity sensor according to claim 1, it is characterised in that the power interface and communication connect Mouth mold block is based on RS485, RS232 or UART communications protocol and peripheral device communication, is powered by external equipment.

A kind of 4. digital conductivity sensor according to claim 1, it is characterised in that the digital signal processing device Also include voltage transformation module, for by 5V voltage conversions into 3.3V voltages.

5. a kind of digital conductivity sensor according to claim 1, it is characterised in that the front end electrode tip uses band The stainless steel electrode of temperature compensation.

6. a kind of digital conductivity sensor according to claim 1, it is characterised in that communication interface uses MAX485 Chip, power interface use AMDS1117, and single-chip microcomputer uses SMT32F030, and power isolation module uses DC100505, measurement Module uses ADS1120.