CN205317966U - High accuracy multichannel automatic meteorological station atmospheric pressure examination appearance - Google Patents

本实用新型公开了一种高精度多通道自动气象站气压检定仪，包括主控制器，均与主控制器相连的参数存储模块、控制按键、复位电路、时钟电路、RS232串口电路、CPLD模块和D/A转换器，以及供电用电源和挂接于CPLD模块扩展输出口的信息显示模块；RS232串口电路的输出端连接有RS232串口信号输出接口，CPLD模块通过接收来自自动气象站的触发信号以固定频率输出脉冲信号于脉冲信号输出接口，D/A转换器通过运放调理电路连接有模拟量信号输出接口。有益效果：实现分别从三个通道输出高精度、互不干扰的模拟电压、触发脉冲、RS232形式的气压信号，输出电信号范围和分辨率能与不同型号自动气象站的采集器匹配。

The utility model discloses a high-precision multi-channel automatic weather station air pressure calibration instrument, which comprises a main controller, a parameter storage module connected to the main controller, control buttons, a reset circuit, a clock circuit, an RS232 serial port circuit, a CPLD module and The D/A converter, and the power supply for power supply and the information display module connected to the expansion output port of the CPLD module; the output end of the RS232 serial port circuit is connected with the RS232 serial port signal output interface, and the CPLD module receives the trigger signal from the automatic weather station to The pulse signal is output at a fixed frequency at the pulse signal output interface, and the D/A converter is connected with an analog signal output interface through an operational amplifier conditioning circuit. Beneficial effects: output high-precision, non-interfering analog voltage, trigger pulse, and RS232 barometric pressure signals from the three channels respectively, and the range and resolution of the output electrical signal can match the collectors of different types of automatic weather stations.

高精度多通道自动气象站气压检定仪High-precision multi-channel automatic weather station barometric pressure calibration instrument

技术领域 technical field

本实用新型涉及一种气压检定仪，特别是涉及一种高精度多通道自动气象站气压检定仪，属于气象仪器计量检定领域。 The utility model relates to an air pressure calibrating instrument, in particular to a high-precision multi-channel automatic weather station air pressure calibrating instrument, which belongs to the field of measuring and calibrating meteorological instruments.

背景技术 Background technique

目前，我国主流自动气象站有CAWS600型、WP3103、ZQZ系列等，一般使用的气压传感器为芬兰Vaisala公司的PTB220，其原理是内置电容性压力传感器，大气压力变化引起电容变化，通过一个高精度的RC振荡电路测量振荡频率反推电容和气压值，而且PTB220可采用RS232形式、触发脉冲和模拟电压三种不同形式的电信号表示气压值。 At present, my country's mainstream automatic weather stations include CAWS600, WP3103, ZQZ series, etc. The commonly used air pressure sensor is the PTB220 of Vaisala Company in Finland. The RC oscillation circuit measures the oscillation frequency reverse capacitance and the air pressure value, and the PTB220 can use three different forms of electrical signals in the form of RS232, trigger pulse and analog voltage to indicate the air pressure value.

CAWS600型自动气象站中的气压传感器PTB220一般采用模拟电压（0-5V）输出。采集器测量电压值并换算成气压。 The air pressure sensor PTB220 in the CAWS600 automatic weather station generally adopts analog voltage (0-5V) output. The collector measures the voltage value and converts it into air pressure.

WP3103型自动气象站中的气压传感器PTB220一般采用触发脉冲输出。采集器在每次测量前，先向PTB220发送触发信号，PTB220收到该触发信号后，输出数量与气压大小成正比、频率5kHz、占空比50%的脉冲。采集器对脉冲计数并换算成气压值。 The air pressure sensor PTB220 in the WP3103 automatic weather station generally adopts trigger pulse output. Before each measurement, the collector sends a trigger signal to PTB220. After receiving the trigger signal, PTB220 outputs pulses whose number is proportional to the air pressure, with a frequency of 5kHz and a duty cycle of 50%. The collector counts the pulses and converts them into air pressure values.

ZQZ系列自动气象站中的气压传感器PTB220一般采用RS232形式字符串输出。气压传感器PTB220以固定波特率将气压数值以字符串形式发送给采集器。采集器通过RS232接收字符串来测量气压值。 The air pressure sensor PTB220 in the ZQZ series automatic weather station generally adopts RS232 form string output. The air pressure sensor PTB220 sends the air pressure value to the collector in the form of a string at a fixed baud rate. The collector receives strings through RS232 to measure air pressure.

然而，自动气象站长期置于野外工作，受恶劣环境影响，其采集器的性能会下降，测量误差增大。气象计量人员需要定期对自动气象站的采集器进行现场检定。采集器气压通道的检定需要一个标准的气压信号源，能模拟气压传感器PTB220输出三种形式的电信号，信号的范围和特征与PTB220一致。采集器测量气压信号源的输出信号，将测量值同设定值比对，判断自动气象站采集器气压通道的测量性能。 However, the automatic weather station has been placed in the field for a long time, affected by the harsh environment, the performance of the collector will decline, and the measurement error will increase. Meteorological metrology personnel need to conduct on-site verification of the collectors of automatic weather stations on a regular basis. The verification of the air pressure channel of the collector requires a standard air pressure signal source, which can simulate the air pressure sensor PTB220 to output three forms of electrical signals, and the range and characteristics of the signal are consistent with those of the PTB220. The collector measures the output signal of the air pressure signal source, compares the measured value with the set value, and judges the measurement performance of the air pressure channel of the automatic weather station collector.

目前，用于自动气象站采集器气压通道检定的仪器十分缺乏。通用的电子测量仪器——函数发生器，能提供模拟电压信号，但输出范围和分辨率不满足CAWS600的要求。WP3103和ZQZ系列检定时所需的电信号则更为特殊，没有满足要求的信号源。另外，已有的能提供RS232形式的气压信号的自动气象站信号模拟器，仍存在输出电信号形式单一，不能兼顾不同型号的自动气象站的不足。 At present, there is a lack of instruments for calibrating air pressure channels of collectors in automatic weather stations. A general electronic measuring instrument - a function generator, can provide an analog voltage signal, but the output range and resolution do not meet the requirements of CAWS600. The electrical signals required for WP3103 and ZQZ series verification are more special, and there is no signal source that meets the requirements. In addition, the existing automatic weather station signal simulators that can provide RS232 air pressure signals still have the disadvantage that the output electrical signal form is single and cannot accommodate different types of automatic weather stations.

实用新型内容 Utility model content

本实用新型的主要目的在于，克服现有技术中的不足，提供一种新型结构的高精度多通道自动气象站气压检定仪，特别适用于不同型号自动气象站气压通道的检定。 The main purpose of the utility model is to overcome the deficiencies in the prior art and provide a high-precision multi-channel automatic weather station air pressure calibrating instrument with a new structure, which is especially suitable for calibrating the air pressure channels of different types of automatic weather stations.

本实用新型所要解决的技术问题是提供结构紧凑、拆装方便、制作容易、安全可靠、实用性强的高精度多通道自动气象站气压检定仪，可实现分别从三个通道输出模拟电压、触发脉冲、RS232形式的气压信号，输出电信号范围和分辨率能与不同型号自动气象站的采集器匹配，而且三种信号的输出高精度、互不干扰，极具有产业上的利用价值。 The technical problem to be solved by the utility model is to provide a high-precision multi-channel automatic weather station air pressure calibration instrument with compact structure, convenient disassembly and assembly, easy manufacture, safety and reliability, and strong practicability, which can output analog voltage from three channels, trigger Pulse and RS232 air pressure signals, the range and resolution of the output electric signal can match the collectors of different types of automatic weather stations, and the output of the three signals is high-precision and does not interfere with each other, which is extremely valuable in industry.

为了达到上述目的，本实用新型所采用的技术方案是： In order to achieve the above object, the technical solution adopted in the utility model is:

一种高精度多通道自动气象站气压检定仪，包括主控制器，均与主控制器相连的参数存储模块、控制按键、复位电路、时钟电路、RS232串口电路、CPLD模块和D/A转换器，以及供电用电源和挂接于CPLD模块扩展输出口的信息显示模块。 A high-precision multi-channel automatic weather station air pressure calibration instrument, including a main controller, a parameter storage module connected to the main controller, control buttons, a reset circuit, a clock circuit, an RS232 serial port circuit, a CPLD module and a D/A converter , and a power supply for power supply and an information display module connected to the extended output port of the CPLD module.

其中，所述RS232串口电路的输出端连接有RS232串口信号输出接口，所述CPLD模块通过接收来自自动气象站的触发信号以固定频率输出脉冲信号于脉冲信号输出接口，所述D/A转换器通过运放调理电路连接有模拟量信号输出接口；所述RS232串口信号输出接口、脉冲信号输出接口和模拟量信号输出接口均用于与自动气象站的数据采集器相连。 Wherein, the output end of the RS232 serial port circuit is connected with an RS232 serial port signal output interface, and the CPLD module outputs a pulse signal at a fixed frequency at the pulse signal output interface by receiving a trigger signal from an automatic weather station, and the D/A converter An analog signal output interface is connected through an operational amplifier conditioning circuit; the RS232 serial signal output interface, pulse signal output interface and analog signal output interface are all used to connect with the data collector of the automatic weather station.

本实用新型进一步设置为：所述主控制器和D/A转换器之间设置有总线隔离电路。 The utility model is further configured as: a bus isolation circuit is arranged between the main controller and the D/A converter.

本实用新型进一步设置为：所述总线隔离电路为四通道的数字隔离器ADUM1401。 The utility model is further configured as: the bus isolation circuit is a four-channel digital isolator ADUM1401.

本实用新型进一步设置为：所述四通道的数字隔离器ADUM1401中的两个工作电源接口之间通过低纹波的DC-DC芯片MEB01Z-05S05D进行电源隔离。 The utility model is further configured as follows: the low-ripple DC-DC chip MEB01Z-05S05D is used for power isolation between the two working power interfaces of the four-channel digital isolator ADUM1401.

本实用新型进一步设置为：所述主控制器采用MSP430系列单片机制作。 The utility model is further set as: the main controller adopts MSP430 series single-chip microcomputer to make.

本实用新型进一步设置为：所述MSP430系列单片机内置有UART模块。 The utility model is further set as: the MSP430 series single-chip microcomputer has a built-in UART module.

本实用新型进一步设置为：所述UART模块为两个，所述MSP430系列单片机通过内置的任意一个UART模块输出TTL电平后通过电平转换芯片max232将TTL电平转换为RS232电平输出给RS232串口信号输出接口。 The utility model is further set as: there are two UART modules, and the MSP430 series single-chip microcomputer outputs TTL level through any built-in UART module, and then converts TTL level into RS232 level through level conversion chip max232 and outputs to RS232 Serial port signal output interface.

本实用新型进一步设置为：所述D/A转换器采用AD5660芯片，所述运放调理电路采用LTC2050芯片，所述运放调理电路由基准源ADR421经UPR型电阻分压后提供基准电压、并由电荷泵反转芯片LTC1983-5提供负电源。 The utility model is further set as follows: the D/A converter adopts the AD5660 chip, the operational amplifier conditioning circuit adopts the LTC2050 chip, and the operational amplifier conditioning circuit provides the reference voltage after the reference source ADR421 is divided by the UPR type resistor, and The negative power supply is provided by the charge pump inverting chip LTC1983-5.

本实用新型进一步设置为：所述参数存储模块采用EEPROM芯片。 The utility model is further configured as: the parameter storage module adopts an EEPROM chip.

本实用新型进一步设置为：所述电源为锂电池，所述信息显示模块为TFT显示屏。 The utility model is further configured as follows: the power supply is a lithium battery, and the information display module is a TFT display screen.

与现有技术相比，本实用新型具有的有益效果是： Compared with the prior art, the utility model has the beneficial effects of:

根据气压值和三种电信号的转换关系，充分利用CPLD模块处理数字时序电路的优势，采用单片机加CPLD模块的架构，并辅以参数存储模块、信息显示模块等，实现分别从三个通道输出高精度、互不干扰的模拟电压、触发脉冲、RS232形式的气压信号，输出电信号范围和分辨率能与不同型号自动气象站的采集器匹配，为不同型号自动气象站采集器气压通道的现场检定和故障判断提供了一种综合的仪器手段。 According to the conversion relationship between air pressure value and three kinds of electrical signals, make full use of the advantages of CPLD module in processing digital sequential circuits, adopt the architecture of single-chip microcomputer plus CPLD module, supplemented by parameter storage module, information display module, etc., to realize output from three channels respectively High-precision, non-interfering analog voltage, trigger pulse, and air pressure signal in the form of RS232. The range and resolution of the output electrical signal can match the collectors of different types of automatic weather stations. Verification and fault judgment provide a comprehensive instrument means.

上述内容仅是本实用新型技术方案的概述，为了更清楚的了解本实用新型的技术手段，下面结合附图对本实用新型作进一步的描述。 The above content is only an overview of the technical solution of the utility model. In order to understand the technical means of the utility model more clearly, the utility model will be further described below in conjunction with the accompanying drawings.

附图说明 Description of drawings

图1为本实用新型高精度多通道自动气象站气压检定仪的结构示意图； Fig. 1 is the structural representation of the utility model's high-precision multi-channel automatic weather station air pressure calibration instrument;

图2为本实用新型高精度多通道自动气象站气压检定仪产生触发脉冲形式的气压信号的电路图； Fig. 2 is the circuit diagram of the air pressure signal of the trigger pulse form produced by the utility model's high-precision multi-channel automatic weather station air pressure calibration instrument;

图3为本实用新型高精度多通道自动气象站气压检定仪产生模拟电压形式的气压信号的电路图； Fig. 3 is the circuit diagram of the air pressure signal of the analog voltage form produced by the utility model's high-precision multi-channel automatic weather station air pressure calibration instrument;

图4为本实用新型高精度多通道自动气象站气压检定仪产生RS232形式的气压信号的电路图； Fig. 4 is the circuit diagram of the air pressure signal of the RS232 form produced by the utility model's high-precision multi-channel automatic weather station air pressure calibration instrument;

图5为本实用新型高精度多通道自动气象站气压检定仪的总线隔离电路； Fig. 5 is the bus isolation circuit of the utility model's high-precision multi-channel automatic weather station air pressure calibration instrument;

图6为本实用新型高精度多通道自动气象站气压检定仪的电源隔离电路。 Fig. 6 is the power isolation circuit of the utility model's high-precision multi-channel automatic weather station air pressure calibrating instrument.

具体实施方式 detailed description

下面结合说明书附图，对本实用新型作进一步的说明。 Below in conjunction with accompanying drawing of description, the utility model is described further.

如图1所示的一种高精度多通道自动气象站气压检定仪，包括主控制器，均与主控制器相连的参数存储模块、控制按键、复位电路、时钟电路、RS232串口电路、CPLD模块和D/A转换器，以及供电用电源和挂接于CPLD模块扩展输出口的信息显示模块；所述RS232串口电路的输出端连接有RS232串口信号输出接口，所述CPLD模块通过接收来自自动气象站的触发信号以固定频率输出脉冲信号于脉冲信号输出接口，所述D/A转换器通过运放调理电路连接有模拟量信号输出接口；所述RS232串口信号输出接口、脉冲信号输出接口和模拟量信号输出接口均用于与自动气象站的数据采集器相连。 A high-precision multi-channel automatic weather station air pressure calibration instrument as shown in Figure 1, including a main controller, a parameter storage module connected to the main controller, control buttons, reset circuit, clock circuit, RS232 serial port circuit, CPLD module and D/A converter, and the information display module of the power supply and the expansion output port of the CPLD module connected to the power supply; The trigger signal of the station outputs a pulse signal at a pulse signal output interface at a fixed frequency, and the D/A converter is connected with an analog signal output interface through an operational amplifier conditioning circuit; the RS232 serial port signal output interface, pulse signal output interface and analog The quantity signal output interface is used to connect with the data collector of the automatic weather station.

为便于现场检定，采用锂电池供电方式，选用低功耗的处理器作为系统的主控制器，为产生RS232形式的气压信号，主控制器最好内置有UART模块。综合考虑，可选用低功耗的TI公司的MSP430系列单片机作为主控制器。并通过16位DAC、隔离器件和信号调理电路产生高精度模拟电压形式的气压信号，而触发脉冲形式通过CPLD模块实现。当前输出气压值和对应的电信号大小通过TFT屏显示。TFT屏占用较多IO口，不宜直接由单片机形式的主控制器驱动，可利用CPLD模块的扩展IO口挂接。采用EEPROM芯片作为参数存储模块，用于存储气压和电信号的换算函数关系、温度补偿参数等。 In order to facilitate on-site verification, a lithium battery is used for power supply, and a low-power processor is selected as the main controller of the system. In order to generate the air pressure signal in the form of RS232, the main controller preferably has a built-in UART module. Considering comprehensively, the MSP430 series MCU of TI Company with low power consumption can be selected as the main controller. The air pressure signal in the form of high-precision analog voltage is generated through 16-bit DAC, isolation device and signal conditioning circuit, and the form of trigger pulse is realized through CPLD module. The current output air pressure value and the corresponding electrical signal are displayed on the TFT screen. The TFT screen occupies a lot of IO ports, so it is not suitable to be directly driven by the main controller in the form of a single-chip microcomputer, and can be connected by using the extended IO ports of the CPLD module. The EEPROM chip is used as a parameter storage module, which is used to store the conversion function relationship of air pressure and electrical signal, temperature compensation parameters, etc.

如图1和图2所示，检定WP3103自动气象站的采集器气压通道时，需要检定仪能提供触发脉冲形式的气压信号，且触发脉冲的时序要同气压传感器PTB220完全一致。采用的CPLD模块实现时序电路具有资源丰富、精度高的优势，可利用EPM240T100C5产生触发脉冲形式的气压信号。 As shown in Figure 1 and Figure 2, when calibrating the air pressure channel of the collector of the WP3103 automatic weather station, it is necessary that the calibrating instrument can provide the air pressure signal in the form of a trigger pulse, and the timing of the trigger pulse must be exactly the same as that of the air pressure sensor PTB220. The CPLD module used to realize the sequential circuit has the advantages of abundant resources and high precision. EPM240T100C5 can be used to generate the air pressure signal in the form of trigger pulse.

如图2所示，输入端TRI接收采集器发来的触发信号，输入端DATA和WR为主控制器与CPLD的通信口，主控制器将气压值对应的脉冲数N通过DATA发送至CPLD。输入端f50M为晶振提供的50MHz时钟信号。输出端PULSE输出N个频率5kHz的脉冲，表示气压大小为(N*0.1)hPa。 As shown in Figure 2, the input terminal TRI receives the trigger signal from the collector, the input terminals DATA and WR are the communication ports between the main controller and CPLD, and the main controller sends the pulse number N corresponding to the air pressure value to the CPLD through DATA. The input terminal f50M is the 50MHz clock signal provided by the crystal oscillator. The output terminal PULSE outputs N pulses with a frequency of 5kHz, indicating that the air pressure is (N*0.1)hPa.

器件mcu_interface为CPLD模块与主控制器的接口电路，DATA为8位数据总线，WR为通信控制信号。若要产生的气压为500hPa，则检定仪在收到触发信号后，需要产生5000个频率为5kHz的脉冲。主控制器通过总线DATA将整数5000写入CPLD模块的器件mcu_interface，并送至端口Num[15..0]输出。 The device mcu_interface is the interface circuit between the CPLD module and the main controller, DATA is the 8-bit data bus, and WR is the communication control signal. If the generated air pressure is 500hPa, the calibrator needs to generate 5000 pulses with a frequency of 5kHz after receiving the trigger signal. The main controller writes the integer 5000 into the device mcu_interface of the CPLD module through the bus DATA, and sends it to the port Num[15..0] for output.

器件f_DIV_5kHz为分频器，将50MHz的时钟分频得到5kHz的脉冲信号。器件Presure_Plus产生使能信号EN，EN通过与非门NAND2控制输出脉冲的个数。TRI没有收到触发信号时，EN保持低电平，输出PULSE始终为高电平。TRI检测到采集器发来的触发信号下降沿开始，要求延时20ms后再输出脉冲。故在器件Presure_Plus中设置变量x，x对5kHz的脉冲计数，从0计数到100时，EN保持低电平，输出端PULSE为高电平。脉冲周期为0.2ms，100个脉冲即延时20ms。x从100计数到(N+100)时，EN保持高电平，使5kHz的脉冲通过与非门由PULSE端输出。采集器将收到的N个脉冲换算成气压值（N*0.1）hPa，N的取值范围为500-11000。 The device f_DIV_5kHz is a frequency divider, which divides the frequency of the 50MHz clock to obtain a 5kHz pulse signal. The device Presure_Plus generates the enable signal EN, and EN controls the number of output pulses through the NAND gate NAND2. When TRI does not receive a trigger signal, EN remains low, and the output PULSE is always high. TRI detects the falling edge of the trigger signal sent by the collector, and requires a delay of 20ms before outputting the pulse. Therefore, the variable x is set in the device Presure_Plus, and x counts 5kHz pulses. When counting from 0 to 100, EN remains low and the output terminal PULSE is high. The pulse period is 0.2ms, and 100 pulses are delayed by 20ms. When x counts from 100 to (N+100), EN maintains a high level, so that the 5kHz pulse is output from the PULSE terminal through the NAND gate. The collector converts the received N pulses into air pressure (N*0.1) hPa, and the range of N is 500-11000.

如图1和图3所示，根据模拟电压形式气压信号的特点，设定气压值后，检定仪输出直流电压，产生模拟电压的范围为0-2.5V。为提高输出电压的精度，可采用低温漂电压基准、高精度DAC、极低失调运放来设计电路。图3中，利用16位的D/A转换芯片AD5660产生模拟电压U1，总线DIN、CLK、CS为其与主控制器的接口。AD5660是ADI公司的16位低功耗、单通道、缓冲电压输出DAC，内置1.25V基准。采用具有长期稳定性的基准源ADR421输出2.5V的基准电压，通过极低温漂(2ppm/℃)的UPR型电阻R2和R4分压得到电压U3。U1和U3经过由极低失调电压（最大3μV）的运放LTC2050构成的减法电路后，得到输出电压U4，U4为满足要求的电压形式的气压信号。图3中所示的LTC1983-5为电荷泵反转芯片，可为运放提供负电源。 As shown in Figure 1 and Figure 3, according to the characteristics of the air pressure signal in the form of analog voltage, after setting the air pressure value, the calibration instrument outputs a DC voltage, and the range of the analog voltage generated is 0-2.5V. In order to improve the accuracy of the output voltage, the circuit can be designed with a low-temperature drift voltage reference, a high-precision DAC, and an extremely low offset operational amplifier. In Fig. 3, the 16-bit D/A conversion chip AD5660 is used to generate the analog voltage U1, and the bus DIN, CLK, CS are the interfaces with the main controller. The AD5660 is a 16-bit low power, single channel, buffered voltage output DAC from Analog Devices with a built-in 1.25V reference. The reference source ADR421 with long-term stability is used to output a 2.5V reference voltage, and the voltage U3 is obtained by dividing the UPR resistors R2 and R4 with a very low temperature drift (2ppm/°C). After U1 and U3 pass through the subtraction circuit composed of the operational amplifier LTC2050 with extremely low offset voltage (maximum 3μV), the output voltage U4 is obtained, and U4 is an air pressure signal in the form of a voltage that meets the requirements. The LTC1983-5 shown in Figure 3 is a charge pump inverting chip that provides a negative supply for an op amp.

如图1和图4所示，本系统采用的430系列单片机可内置有两个UART模块，利用其中的UART0产生串口形式的气压信号，ZQZ系列自动站接收RS-232形式气压信号的波特率为2400。初始化寄存器将UART0的波特率设置为2400。单片机的UART0输出为TTL电平，利用电平转换芯片max232将其转换为RS232电平；其中MCU-TXD0、MCU-RXD0与单片机的UART0相连，XD、RXD输出的气压信号与自动气象站的采集器相连。D1和D2为静电保护的瞬变二极管。 As shown in Figure 1 and Figure 4, the 430 series single-chip microcomputer used in this system can have two built-in UART modules, and UART0 is used to generate the air pressure signal in the form of a serial port, and the baud rate of the ZQZ series automatic station to receive the air pressure signal in the form of RS-232 for 2400. The initialization register sets the baud rate of UART0 to 2400. The UART0 output of the single-chip microcomputer is TTL level, which is converted to RS232 level by using the level conversion chip max232; among them, MCU-TXD0 and MCU-RXD0 are connected with UART0 of the single-chip microcomputer, and the air pressure signal output by XD and RXD is collected by the automatic weather station connected to the device. D1 and D2 are transient diodes for electrostatic protection.

本系统作为自动气象站采集器气压通道的检定仪器，要求输出气压信号的最大允许误差小于采集器测量误差的1/3。RS232和脉冲形式的气压信号为数字量，抗干扰能力强。而模拟电压形式的气压信号的产生电路极易受到环境温度、数字通道的干扰。除注重器件选型，选择高精度DAC、低失调运放外，还可采取隔离、补偿等措施来保证输出信号的高精度。 This system is used as a verification instrument for the air pressure channel of the collector of the automatic weather station, and the maximum allowable error of the output air pressure signal is required to be less than 1/3 of the measurement error of the collector. The air pressure signals in RS232 and pulse form are digital quantities, with strong anti-interference ability. However, the generation circuit of the air pressure signal in the form of analog voltage is extremely susceptible to interference from ambient temperature and digital channels. In addition to paying attention to device selection, choosing high-precision DACs and low-offset operational amplifiers, measures such as isolation and compensation can also be taken to ensure high-precision output signals.

如图5所示，即为总线隔离措施，为使模拟电压形式的气压信号产生电路与数字通道的回路完全独立。防止主控制器和DAC通信结点间电流的流动，须进行通道隔离。本系统选用四通道iCoupler技术的数字隔离器ADUM1401将主控制器和DAC的通信总线隔离，其中，VDD1、GND1为数字通道的电源和地，CS、CLK、DIN为与主控相连的片选、时钟、数据总线，VDD2、GND2为模拟电压通道的电源和地，G-CS、G-CLK、G-DIN为隔离后与模拟电压产生电路的DAC5660相连的片选、时钟、数据总线。 As shown in Figure 5, it is a bus isolation measure, in order to make the air pressure signal generation circuit in the form of analog voltage completely independent from the circuit of the digital channel. To prevent the flow of current between the host controller and the DAC communication node, channel isolation is required. This system uses the digital isolator ADUM1401 with four-channel iCoupler technology to isolate the communication bus between the main controller and the DAC. Among them, VDD1 and GND1 are the power supply and ground of the digital channel, and CS, CLK and DIN are the chip select, Clock and data bus, VDD2 and GND2 are the power supply and ground of the analog voltage channel, G-CS, G-CLK and G-DIN are the chip select, clock and data bus connected to the DAC5660 of the analog voltage generation circuit after isolation.

如图6所示，即为电源隔离措施，可选用极低纹波的DC-DC芯片MEB01Z-05S05D将四通道数字隔离器ADUM1401的工作电源VDD1和VDD2隔离。器件MEB01Z的输入电压具有较宽的取值范围：4.75-5.25V，且其纹波￡10mV，输出电压5V，输出电流达到200mA，功率1W，所以完全满足电压产生模块的功耗要求。 As shown in Figure 6, it is a power isolation measure. The ultra-low ripple DC-DC chip MEB01Z-05S05D can be used to isolate the working power supply VDD1 and VDD2 of the four-channel digital isolator ADUM1401. The input voltage of the device MEB01Z has a wide range of values: 4.75-5.25V, and its ripple is ￡10mV, the output voltage is 5V, the output current reaches 200mA, and the power is 1W, so it fully meets the power consumption requirements of the voltage generation module.

本实用新型的创新点在于，可提供一种高精度、多通道（RS-232形式、模拟电压、触发脉冲）同时输出而互不干扰的新型气压检定仪。经测试表明，三个通道输出的气压信号范围均为500-1100hPa，覆盖了自动气象站的测量范围；最大误差±0.02hPa，远低于自动气象站的最大测量误差±0.3hPa；从而可为不同型号的自动气象站提供综合的计量检定。 The innovation of the utility model is that it can provide a new type of air pressure calibration instrument with high precision and multi-channel (RS-232 form, analog voltage, trigger pulse) output simultaneously without interfering with each other. The test shows that the pressure signal range output by the three channels is 500-1100hPa, covering the measurement range of the automatic weather station; the maximum error is ±0.02hPa, which is far lower than the maximum measurement error of the automatic weather station ±0.3hPa; Various types of automatic weather stations provide comprehensive metrological verification.

以上所述，仅是本实用新型的较佳实施例而已，并非对本实用新型作任何形式上的限制，虽然本实用新型已以较佳实施例揭露如上，然而并非用以限定本实用新型，任何熟悉本专业的技术人员，在不脱离本实用新型技术方案范围内，当可利用上述揭示的技术内容做出些许更动或修饰为等同变化的等效实施例，但凡是未脱离本实用新型技术方案的内容，依据本实用新型的技术实质对以上实施例所作的任何的简单修改、等同变化与修饰，均仍属于本实用新型技术方案的范围内。 The above are only preferred embodiments of the present utility model, and do not limit the utility model in any form. Although the utility model has been disclosed as above with preferred embodiments, it is not intended to limit the utility model. Any Those who are familiar with this profession, without departing from the scope of the technical solutions of the present utility model, can use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but all without departing from the technical solutions of the present utility model The content of the scheme, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the utility model still belong to the scope of the technical solution of the utility model.