英国阿尔法Alphasense氢气传感器 H2-BF

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H2S传感器应用电路

AAN 105-03DESIGNING A POTENTIOSTATIC CIRCUITIntroductionIn a three-electrode sensor, each electrode has a specific use:• The working electrode responds to the target gas, either oxidising or reducing the gas, creating a current flow that is proportional to the gas concentration. This current must be supplied to the sensor through the counter electrode.• The reference electrode is used by the potentiostatic circuit to maintain a fixed potential at the working electrode. The working electrode potential must be maintained at the same potential as the reference electrode potential for unbiased sensors, or with an offset for sensors that require biasing.• The counter electrode completes the circuit with the working electrode, reducing some chemical species (normally oxygen) if the working electrode is oxidising, or oxidising if the working electrode is reducing the target gas. The potential of the counter electrode is allowed to float, sometimes changing as the gas concentration increases. The potential on the counter electrode is not important, so long as the potentiostat circuit can provide sufficient voltage and current to maintain the working electrode at the same potential as the reference electrode. Figure 1 is a circuit diagram of a zero bias potentiostat circuit. Refer to this during the discussions below.Figure 1 Preferred potentiostat circuit for zero bias toxic gas sensors. ICs require +/-, not single ended power supply.© Alphasense Limited Page 1 of 5 February 2003A typical potentiostat circuit consists of three parts:1 Control circuit with bias voltage, if required2 Current measuring circuit3Shorting FET to connect the working electrode to the reference electrode when power is off Control CircuitThe control op amp (IC2 in figure 1) provides the current to the counter electrode to balance the current required by the working electrode.The inverting input into IC2 is connected to the reference electrode and must not draw any significant current from the reference electrode. An op amp with an input bias current of less than 5nA is recommended.When switching on the circuit, the depletion mode JFET (Q1 in Fig 1)goes to a high impedance state and IC2 provides the current to maintain the working electrode at the same potential as the reference electrode. Any offset due to the input offset voltage in IC2 will therefore cause a sudden shift in potential at switch-on. Toxic gas sensors have a large capacitance, so significant currents can flow for small potential shifts, so ensure that your op amp has a low offset voltage, certainly less than 1 mV and preferably less than 100µV; also check the op amp offset voltage at the maximum usage temperature.Typically, for an oxidisable gas (such as CO) with a platinum reference electrode, the counter electrode will be -300 to -400mV from the ground potential. However, if hydrogen ions rather than oxygen molecules are reduced, then the potential could be as large as -1.05V. Also, reducing gases (such as NO2 or Chlorine) force the counter electrode to oxidise water, evolving oxygen; in this case the potential relative to the reference electrode is between +600 and +800 mV, depending on the type of reference electrode. Therefore, you must allow IC2 enough voltage swing to drive the counter electrode to the required potential and with sufficient current demanded by the sensor. If the circuit is unable to do this, then extreme non-linearities will occur at higher concentrations. It is best to allow ±1.1V swing on IC2 (plus any imposed bias voltage). This means that for a CO or H2S sensor the counter electrode wants to be typically -350 mV below the ground point, so IC2 needs a negative supply. If you are using a single ended low voltage power supply, pay particular attention to the available output swing on the op amp at the required current.Table 1 below shows the maximum generated steady state current for each type of sensor. At full scale no sensor generates more than 210µA, but allow at least 500µA for a general purpose circuit, although this can be decreased for specific, well tested sensor/ circuit combinations. Beware- when switching the circuit ON in the presence of an electroactive gas or when a new sensor is first connected, the sensor may give a surge current of several mA that may cause IC1 to clamp, depending on the current drive capacity of IC1; it is unlikely that IC1 can maintain the virtual earth on its inverting input with a high feedback resistor during such a high current transient. Always connect the sensor before powering the circuit.Circuit stability and noise reduction in the control circuit relies on R1, R2, C1 and C2; C2 may not be necessary for certain op amps. If eliminating C2, then C1 may be increased- between 10 and 100 nF. Suggested op amps are OP90 (single op amp) and OP 296 (dual op amp).© Alphasense Limited Page 2 of 5 February 2003Bias voltageNormally, Alphasense toxic gas sensors are operated in the zero bias mode; however, certain sensors, such as NO sensors, require a bias voltage: typically ±150 or 300mV for an NO sensor. Alternatively, sensor cross-sensitivity to certain gases can be enhanced by adding a bias voltage.BEWARE! performance can also be degraded if you bias incorrectly! Remember that biasing a normally unbiased sensor may damage the sensor and certainly voids the sensor warranty. Consult Alphasense for further advice.If you wish to inject a bias voltage then also ensure that your bias voltage is stable: changes of even a few mV can affect sensitivity to gases and rapid changes in the bias voltage by only a mV will generate transient effects for up to hours on the sensor output. A simple method of biasing the sensor is shown in figure 2 below. The 10K load resistor to ground can be removed to reduce the current on V bias.Biasing should be maintained when the instrument is switched off - this is normally accomplished by using a button cell battery that remains on at all times. In this case, the input offset of IC2 is not critical, but its drift with temperature etc. must be kept small.Current Measuring CircuitThe measuring circuit is a single stage op amp (IC1) in a transimpedance configuration; the sensor current is reflected across R4, generating an output voltage relative to the virtual earth. C3 reduces high frequency noise. It is sometimes desirable to use two opamp stages to give the required output; the first stage should use a low value for R4 to allow the circuit to oppose the sensor current in transient conditions, followed by a second voltage gain stage to give the required output. The input offset voltage of IC1 will add to the sensor bias voltage (as the working electrode will be offset from 0V) so the input offset should be kept low. Remember that the generated current can be either positive or negative: sensors that oxidise at the working electrode (e.g. CO) generate a © Alphasense Limited Page 3 of 5 February 2003current into IC2, while reducing working electrodes (e.g. Cl2 or NO2) sink a current. So for the second case, ensure that IC2 has adequate current sinking capability.The measuring circuit uses a combination of the (load resistor (R load) plus internal sensor resistance) and the (internal sensor capacitance) to establish an RC circuit; the selection of R load is a compromise between fastest response time (low resistance R load) and best noise (high resistance R load): this RC circuit affects both the rms noise and the response time: the response time increases linearly with increasing R load resistance, while noise decreases rapidly with increasing R load resistance. If you need highest resolution, then forfeit fast response time. Likewise, if fast response time is critical, then reduce the resolution of your display or sample the signal faster and average over several readings in software to eliminate jitter. Due to the low impedance nature of the circuit, it is better to use an opamp with low noise current (usually at the expense of noise voltage)to get the best overall noise performance.As sensor current flows through R load, there will be a small change to the sensor bias potential. This has the effect of increasing the sensor settling time as the sensor will require a short time to re-stabilise when gas is applied, but this transient will normally not be seen except at high gas concentrations and high R load resistance.Refer to Table 1 below to calculate the required gain for your measuring circuit. If your detector/ instrument does not use the full scale of the sensor, then simply multiply the Sensitivity by your Range to determine the maximum current from the sensor. Since the sensitivity is the typical value, allow 20% more than the typical full scale output into your A/D converter.Sensor FullScale(ppm)Sensitivity(nA/ppm)(typical)Full Scaleoutput(µA)Full Scaleoutput(V)Calibrationpoint(ppm)CO-BF, CO-B1, CO-BX1,000100100 1.00 400 CO-AF1,00070700.70400 CO-AX2,00065130 1.30400 CO-AE 10,00030300 3.00 2,000 CO-DF1,00040740.74400 H2S-AH 501,200600.60 20 H2S-BH502,000850.8520 H2S-A1 100750750.75 20 H2S-B1200370740.7420 H2S-BE2,00090180 1.80 400 H2S-AE2,000105210 2.10400 H2S-D1100140140.1420 SO2-AF20500100.10 20 SO2-BF100350350.3520 SO2-AE2,00070140 1.40400 NO2-A1 20-3508-0.08 10 NO2-B120-75022-0.2210 NO2-AE200-35070-0.75100 NO-A1,-B1250400100 1.0050 NO-AE1,000100100 1.00400 Cl2-A120-3708-0.0710 CL2-B120-900220.2210 Table 1. List of output parameters and calibration point for Alphasense toxic gas sensors.© Alphasense Limited Page 4 of 5 February 2003Shorting FETIt is normal practice to add a shorting FET for unbiased sensors so that the reference and working electrodes are shorted together (with a residual resistance of a few tens of ohms) when power is removed from the circuit. This ensures that the working electrode is maintained at the same potential as the reference electrode when the circuit is switched off. The shorting FET is normally open circuit as long as power is applied. This “zero bias” state ensures that when you switch the circuit back on, the sensor is ready immediately. If you do not use a shorting FET and leave the sensor open circuit when the circuit is off, the toxic gas sensor will take a few hours to stabilise when next switched on.If you are supplying a bias voltage through IC2, then when you switch off the circuit, the sensor will be zero biased and hence when you reapply a bias voltage it will take a significant time (up to several hours) for the sensor to re-establish equilibrium. It is recommended that, for biased circuits, the bias voltage be maintained on at all times and the shorting FET not used. This will not affect the operating life of the sensor.The JFET (Q1) should be a p-type FET. Recommended FET types include surface mount or TO-92 packages as per Table 2 below.Manufacturer Product Code TypeSiliconix SST177Surface MountSiliconix J175TO-92Siliconix J176TO-92Siliconix J177TO-92Fairchild J175TO-92Table 2. Recommended p-FETs for short circuiting reference and working electrodes when the potentiostat circuit is off.Noise, RFI/EMI ScreeningIdeally, the measuring and controlling op amps in a potentiostat are fitted directly underneath the sensor to keep the shortest leads because of the low impedance and low sensor currents. Alphasense Application Note AAN 103 gives further advice on reducing noise and improving RFI/EMI screening.Sensor CalibrationNote that toxic gas sensor sensitivities are variable,typically ±15%. So you must calibrate in software to correct for sensor-to-sensor sensitivity variations. Alphasense maintains a database of the sensitivity of every sensor tested at Alphasense, but remember that sensitivity will drift downwards with time, typically 0.5% to 2% per month, depending on the sensor type, relative humidity and gas concentration/ temperature conditions. See Application Note AAN 108 for more information.It is also normal to correct for temperature dependence of the sensitivity; zero current is not normally temperature corrected, but for measurements requiring high accuracy at low concentrations, contact Alphasense for advice.© Alphasense Limited Page 5 of 5 February 2003。

氢气H2浓度检测探头

氢气H2浓度检测探头氢气H2浓度检测探头氢气H2浓度检测探头产品描述：氢气H2浓度检测探头适用于各种环境和特殊环境中的氢气H2氢气H2气体浓度和泄露，在线检测及现场声光报警，对危险现场的作业安全起到了预警作用，此仪器采用进口的电化学传感器和微控制器技术，具有信号稳定，精度高，重复性好等优点，防爆接线方式适用于各种危险场所，并兼容各种控制器，PLC,DCS等控制系统，可以同时实现现场报警和远程监控，报警功能，4-20mA标准信号输出，继电器开关量输出。

氢气H2浓度检测探头产品特性：进口电化学传感器具有良好的抗干扰性能，适用寿命8年。

采用先进微处理技术，响应速度快，测量精度高，稳定性和重复性好。

检测现场具有具有现场声光报警功能，气体浓度超标即时报警，是危险场所作业的安全保障。

4现场带背光大屏幕LCD显示，直观显示气体浓度，类型，单位，工作状态等。

5独立气室，更换传感器无须现场标定，传感器关键参数自动识别。

6全量程范围温度数字自动跟踪补偿，保证测量准确性。

检测气体：空气中的氢气H2气体检测范围：0~100ppm,0~200ppm,0~1000ppm,0~1000ppm,0~5000ppm,10 0%LEL可选。

分别率：0.01ppm(0~100ppm);0.1ppm(0~1000ppm);1ppm(0~10000ppm 以上)；0.1LEL.工作方式：固定式连续工作，扩散式，管道式，流通时，泵吸式可选。

检测误差：≦1%（F.S）响应时间：≦10S输出信号：电流信号输出4-20MA报警方式：2路无源节点信号输出，报警点可设置。

工作环境：-20℃~50℃(特殊要求：（-40℃~+70℃)相对湿度：≦90%RH工作电压：DC12~30V传感器寿命：3年防爆形式：探头变送器及传感器均为隔爆型。

防爆等级：Exd II CT6连接电缆：三芯电缆(单根线径≧1.5mm)；建议选用屏蔽电缆。

连接距离：≦1000m.防护等级：IP65.外形尺寸：183X143X107mm.重量：1.5Kg.氢气H2浓度检测探头简单介绍:氢气H2浓度检测探头●自动温度补偿，零点，满量程漂移补偿●防高浓度气体冲击的自动保护功能●全软件校准功能，用户也可自行校准，用3个按键实现，操作简单●二线制4-20mA输出氢气H2浓度检测探头应用场所医药科研、制药生产车间、烟草公司、环境监测、学校科研、楼宇建设、消防报警、污水处理、工业气体过程控制石油石化、化工厂、冶炼厂、钢铁厂、煤炭厂、热电厂、、锅炉房、垃圾处理厂、隧道施工、输油管道、加气站、地下燃气管道检修、室内空气质量检测、危险场所安全防护、航空航天、军用设备监测等。

氢气浓度传感器原理 fis

氢气浓度传感器原理 fis氢气浓度传感器原理氢气浓度传感器是一种可以测量氢气浓度的传感器，其原理主要是利用了氢气与其它气体之间的反应来检测氢气的浓度。

传感器主要由以下几个部分组成：1.感应元件：感应元件是氢气浓度传感器中最为关键的部分。

它是一个金属合金制成的感应层，可以在接触氢气时发生化学反应，通过感应层反应后的电流信号来测量氢气的浓度。

此外，感应元件还可以直接检出氢气分子内部的构造和相关信息。

2.芯片：芯片是氢气浓度传感器中的传感器芯片，主要用于测算感应元件发生反应后的电流信号，并将这些信号转换为具体的氢气浓度数值。

3.电路：电路是指氢气浓度传感器中的传输电路，主要用于传输芯片测算出的氢气浓度数值。

以上三个部分的紧密组合，构成了氢气浓度传感器。

氢气浓度传感器的工作原理如下：当氢气接触感应元件时，由于氢气与感应元件之间的反应，会产生电流信号。

这个电流信号经过宽带放大后，可以在芯片中被检测到，并通过内部布局和计算，被转换成实际的氢气浓度值。

最后传输电路将这个处理好的氢气浓度值传输到数据记录系统以供分析和处理。

值得注意的是，氢气浓度传感器只能测量氢气气体的浓度，而不能测量其它气体。

因此，为了提高氢气浓度传感器的可靠性，需要对其进行定期维护和校验。

通过定期维护和校验，可以及时发现氢气浓度传感器中的任何问题，并及时处理，以确保其在工作时的准确性、稳定性和长期性。

总之，氢气浓度传感器的原理是基于感应元件和芯片之间的电信号转换，通过测量氢气与感应元件间的反应信号来检测氢气浓度。

在使用过程中需要进行定期维护和校验，以确保其在工作时的准确性、稳定性和长期性。

氢气浓度传感器原理

氢气浓度传感器原理
氢气浓度传感器的原理
氢气浓度传感器是一种能够检测氢气浓度的传感器，也被称为氢气探
测器。

它通常用于工业领域，以检测氢气泄漏或生产过程中的氢气浓
度变化。

氢气浓度传感器的原理基于化学反应。

传感器内部通常包含敏感元件
和电路板两部分组成。

敏感元件通常由氧气和银涂层的二氧化钼或三
氧化钨材料构成。

当氢气进入传感器时，它与氧气反应生成水，从而
使银涂层的颜色发生变化。

传感器内的电路板会对银涂层的颜色变化
进行监测并将其转化为电信号输出。

根据传感器的不同类型，检测结果会以数字信号或模拟信号形式输出。

数字信号输出通常是通过RS485或MODBUS等协议。

而模拟信号输出可以是电压、电流或频率形式，需要进一步处理才能得到实际的氢
气浓度值。

氢气浓度传感器的工作原理比较简单，但是它的响应时间和精度会受
到多种因素的影响。

例如，传感器的响应速度取决于敏感元件的厚度
和活性氧的反应速率。

传感器的精度则需要考虑银涂层的均一性和传
感器周围环境的影响因素（如温度和湿度）。

总的来说，氢气浓度传感器是一种可靠且重要的检测氢气浓度的传感器。

在使用时，需要选择适当的传感器类型并注意其应用环境，以确保传感器的准确性和稳定性。

globalsensor 4S-H2S氢化氢传感器说明书

最大S/C电流基本性能灵敏度700±150nA/ppm 量程0～100ppm 基线漂移＜±2ppm 响应时间（T90）＜20s(典型值15s)恢复时间（T10）＜20s(典型值15s)线性度线性可重复性＜±2%使用环境工作温度范围-40℃～+55℃工作气压范围800～1200mbar 工作湿度范围15%RH～90%RH寿命质保输出漂移＜15%每年使用寿命＞24个月（空气中）质保12个月（发货日起）推荐储存温度0～20℃（密闭容器）电性分辨率＜0.1ppm 推荐负载电阻10Ω本安特性2000ppm最大电流0.2mA 最大O/C电压 1.3V ＜1.0A下图显示了不同温度下传感器的灵敏度变化情况（误差1％）。

下表显示的交叉敏感度数据是从大量的试验获得，数值可能随着传感器的生产批次及测试环境的不同而变化，因此，为了获得更准确的数据，请使用相应的气体校准仪器。

如果用交叉敏感气体进行校准，则不保证其标定和测量的准确性。

我们努力保证本文档的准确性，同时为了产品的持续优化升级，我们保留更改的权利，如有变更恕不另行通知。

对于超出本文档所规定条件而使用传感器的，我们不承担保修，不承担因此造成的任何损失。

本文档规格参数是在环境条件：温度20℃、相对湿度50%RH、一个标准大气压下测得，超出范围的数据不做保证。

受不同批次影响，测试参数略有差异，因此本数据手册仅供参考。

4S-H2S -40-30-20-1001020304050平均值82%85%87%90%94%96%100%103%104%106%+95%置信区间 107%106%104%100%97%95%92%89%87%84%-95%置信区间104%102%101%100%95%92%89%85%83%81%4S-H 测试气体浓度(PPM)气体2S 反应值(PPM)050NH305000CO2＜2100CO 020CL20100C2H4＜0.550NO 05NO2020SO2。

氢气传感器

ห้องสมุดไป่ตู้
03 氢气传感器的研究进展及技术挑战
氢气传感器的研究进展及技术创新
氢气传感器的研究进展
• 新型材料的研发：提高传感器的灵敏度和稳定性 • 制备工艺的优化：降低传感器成本，提高生产效率 • 集成化技术的应用：实现传感器的小型化和智能化
氢气传感器的技术创新
• 微纳制造技术：利用微纳制造技术制备高精度、高灵敏度的传感器 • 人工智能算法：结合人工智能算法，提高传感器数据处理能力 • 无线通信技术：实现传感器的无线数据传输，提高应用便捷性
氢气传感器在新能源领域的应用案例
新能源领域简介
• 包括太阳能、风能、氢能等清洁能源领域 • 具有可持续发展的前景
氢气传感器在新能源领域的应用
• 氢气储存与运输：监测氢气储存和运输过程中的氢气浓度，确保安全 • 发电设备监控：监测新能源发电设备中的氢气浓度，优化设备运行 • 安全防护：检测新能源设备中的氢气泄漏，预防安全事故
氢气传感器的工作方式
• 电化学传感器：通过氢气与电极之间的化学反应产生电流信号 • 光学传感器：利用氢气与特定光敏材料之间的吸收或发射光谱变化 • 热导传感器：通过测量氢气与传感器材料之间的热导率变化来检测氢气浓度
氢气传感器的分类及特点
氢气传感器的分类
• 按检测原理分：电化学传感器、光学传感器、热导传感器等 • 按响应速度分：快速响应传感器、慢速响应传感器 • 按测量范围分：高浓度传感器、低浓度传感器
DOCS SMART CREATE
氢气传感器研究与应用
CREATE TOGETHER
DOCS
01 氢气传感器的原理及分类
氢气传感器的原理及工作方式
氢气传感器的原理
• 通过检测氢气浓度变化来识别氢气的存在 • 利用氢气与特定材料之间的化学反应或物理吸附作用 • 产生可测量的信号变化，如电阻、电压或电流等

H2氢气浓度传感器

H2氢气浓度传感器H2氢气浓度传感器特点：★整机体积小,重量轻★高精度,高分辨率,响应迅速快.★上、下限报警值可任意设定，自带零点和目标点校准功能，内置温度补偿，维护方便.★数据恢复功能，免去误操作引起的后顾之忧.★外壳采用特殊材质及工艺，不易磨损，易清洁，长时间使用光亮如新.H2氢气浓度传感器技术参数：★进口电化学传感器具有良好的抗干扰性能，使用寿命长达3年;★采用先进微处理器技术，响应速度快,测量精度高，稳定性和重复性好;★全量程范围温度数字自动跟踪补偿，保证测量准确性;★半导体纳米工艺超低功耗32位微处量器;★全软件自动校准,传感器多达6级目标点校准功能,保证测量的准确性和线性,并且具有数据恢复功能;★防高浓度气体冲击的自动保护功能H2氢气浓度传感器结构图：H2氢气浓度传感器接线示意图:H2氢气气体传感器参数工作电压DC5V±1%/DC24±1%波特率9600测量气体H2氢气气体检测原理电化学采样精度±2%F.S响应时间<30S重复性±1%F.S工作湿度10-95%RH，(无冷凝)工作温度-30～50℃长期漂移≤±1%（F.S/年）存储温度-40～70℃预热时间30S工作电流≤50mA工作气压86kpa-106kpa安装方式7脚拔插式质保期1年输出接口7pIN外壳材质铝合金使用寿命2年外型尺寸(引脚除外)33.5X31 21.5X31测量范围详见选型表输出信号TTL(标配)0.4-2.0VDC(常规)/4-20mA 数字信号格式数据位:8;停止位:1;校验位:无;传感器PIN脚定义图:传感器应用场所：医药科研、学校科研、制药生产车间、烟草公司、环境检测、楼宇建设、消防报警、污水处理、石油石化、化工厂、冶炼厂、钢铁厂、煤炭厂、热电厂、锅炉房、加气站、垃圾处理厂、隧道施工、输油管道、工业气体过程控制、室内空气质量检测、地下燃气管道检修、危险场所安全防护、设备检测等。

氢气传感器

氢气传感器氢是一种清洁可再生能源载体，能够为汽车提供动力，而唯一排放物是水，氢燃料电池被确认为新能源车的优选方案。

但是，氢气和空气混合时却极易燃，因而需要特别有效的传感器进行监控。

探查氢气非常具有挑战性。

此类气体不可见、无味，但是易挥发，极易燃，空气中只需含有4%的氢气就能产生氢氧气体，有时也称为氢氧混合气（knallgas），最小的火花都能将此类气体点燃。

为了保证未来氢燃料汽车以及相关基础设施的安全，必须探测空气中微小含量的氢气，而且氢气传感器的响应速度必须足够快速，以便在起火发生之前探测到泄露的氢气。

鉴于氢气在食品卫生、能源动力、军事国防等领域的广泛使用以及不安全性，在使用氢气时必须对其浓度进行检测。

国内外已经进行了大量关于氢气传感器的研究，目前氢气传感器主要有电化学型、电学型、光学型三大类。

一、电化学型氢气传感器电化学型氢气传感器是将化学信号转变为电信号从而实现氢气浓度检测的氢气传感器。

电化学型传感器由两个电极组成，采用一个电极作为传感元件，另一个电极作为参考电极，当氢气与传感电极发生电化学反应时，电极上的电荷传输或电气性质会发生改变，传感器通过检测相应物理量的变化实现氢气浓度检测的目的。

电化学型氢气传感器又可分为两类:电流型与电势型。

1）电流型氢气传感器电流型传感器的正常工作温度范围为-20℃至80℃。

通过比较不同的催化电极的制备方法(溅射镀膜法、化学镀膜法、铂黑模压法等)和相应传感器的性能，得出溅射镀膜法制备的铂催化电极的活性最高，性能稳定，可以在0至104ppm 的范围内实现氢气浓度的快速检测，传感器响应时间为30s，灵敏度为4μA /100ppm。

温度、压强和湿度变化都对测量结果影响较大。

2）电势型氢气传感器电势型传感器是通过测量传感电极和参考电极之间的电势差来测量氢气浓度的，其应用范围比较广泛，可以检测常温或高温下气体、水溶液、溶态金属中的氢气含量。

从传感器本身来看，电势型氢气传感器与自身的体积和结构几乎不相关，因此适合微型化生产是其一大优势;从测量信号来看，电流型氢气传感器的响应与氢气浓度成线性关系，电势型氢气传感器与氢气浓度成对数关系，因此，电流型氢气传感器在氢气浓度较低时具有更高的灵敏度。

氢气传感器使用方法

氢气传感器使用方法
氢气传感器是一种可以测量空气中氢气浓度的仪器。

在使用氢气传感器时，需要注意以下事项：
1. 氢气传感器的工作原理是利用化学反应产生电流，因此在测量前需要预热一段时间。

2. 在测量前，需要将氢气传感器连接到读数器或数据记录仪。

3. 确保氢气传感器的工作温度范围和测量范围符合实际应用要求。

如果需要测量高浓度氢气，需要选择相应的传感器。

4. 在测量时，需要将氢气传感器置于待测氢气的近处，以保证测量准确。

5. 在使用氢气传感器时，需要避免接触到有害化学物质，以免对传感器造成损坏或误差。

6. 氢气传感器的使用寿命有限，需要定期进行校准和更换。

校准时需要使用校准气体，按照说明书操作。

7. 氢气传感器存放时需要干燥、防水、避免受到机械振动等影响，保证传感器的正常使用寿命。

以上是氢气传感器的使用方法及注意事项，希望能对读者有所帮助。

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B4系列传感器使用SOP

Alphasense四电极电化学传感器使用SOP1.传感器简述英国Alphasense的四电极电化学传感器，包括B4与A4系列，是针对大气环境检测而开发的高分辨率传感器，目前可稳定使用的有六种，即CO、SO2、NO2、O3、NO、H2S。

区别于常规的三电极电化学传感器，四电极传感器多出一个辅助电极，用于补偿零点电流，使其具有更好的响应时间和抗干扰特性，适用于固定及便携设备，城区/室内空气检测及烟气分析。

2.传感器的优势四电极传感器在结构上没有发生大的变化，但性能上有了质的飞越，能够做到ppb级分辨率，对于大气环境空气质量检测，在不降低检测精度的基础上，多了一种低成本的选择，尤其是配置原厂的开发板ISB模块，不仅降低了前期研发难度，还推进了项目进度，更有利于再现产品的优越性能。

3.传感器的基本参数传感器型号量程(ppm)灵敏度(nA/ppm)分辨率(ppb)过载(ppm)H2S-B40~1001450~20501200CO-B40~1000420~65042000NO-B40~20500~8501550NO2-B43F0~20-175~-4501550SO2-B40~100275~4755200OX-B4310~20-225~-550(O3)1550 0~20-250~-650(NO2)15504.传感器后期使用的硬件处理部分详见“ISB Rev4-Schematic.pdf”。

5.单传感器无ISB模块的标定问题对于B4高分辨率传感器，依然同常规三电极类似，两点标定，注意温度，其中基本步骤如下：1）传感器安装后初次上电老化24小时以上方可进行进一步操作；2）传感器安装放置在清洁空气中至少6小时(可包含在步骤1）中)；3）应用零点空气（人工合成或纯净/净化的零点空气）通气20分钟，记录WE(OP1)和Aux(OP2)的输出电压V WE0和V AE0；4）应用低浓度标准气体，通气直止传感器输出稳定，记录WE(OP1)和Aux(OP2)的输出电压V WE和V AE；5）用工作电极和辅助电极的电压减去两个电极对应的零点输出电压，即V WE-V WE0和V AE-V AE0。

氢气浓度传感器是什么？

氢气浓度传感器是什么？氢气浓度传感器在常温下对氢气非常敏感且具有很好的选择性，可以作为检测环境中氢气浓度的传感器，出于生产生活中对安全的要求，快速、灵敏的氢气传感器是十分必要的，能够及时避免爆炸的可能性。

下面随小编去了解下氢气浓度传感器。

一、氢气浓度传感器分类1、半导体型传感器以电阻型半导体传感器为例:主要以sno2,zno,wo3等金属氧化物为气敏材料,例如:国产qm系列氢气传感器就是以sno2作为氢气敏感材料,故也称金属氧化物半导体氢气传感器。

其工作原理是:当吸附氢气后,氢气作为施主释放出电子,与化学吸附层中的氧离子结合,于是载流子浓度发生变化,该变化值与氢气体积分数存在一定的函数关系。

2、热电型传感器首先,在基片上沉积一层热电材料,然后,在热电材料表面的某一部分沉积一层催化金属,如,pt,pd等,最后,分别在催化金属层、热电薄膜层(表面上无催化金属)引出电极,即获得最为简单的热电型氢气敏感元件。

当此敏感元件暴露在含氢气的环境中在催化金属的,作用下,氢气与氧气反应生成水蒸汽并放出热量,于是,沉积有催化金属的一端温度高,为热端,无催化金属的一端温度低,为冷端,由于热电材料的热电发电效应(seebeck效应),将这种热端与冷端之间的温差转换为温差电势,以电信号的形势输出,从而实现对氢气的检测。

3、光纤传感器由于多种固态氢气传感器使用的都是电信号,一个共同的弊端就是可能产生电火花,对于氢气体积分数较高的环境来说存在极大的安全隐患。

而光纤传感器使用的是光信号,所以,适用于易爆炸的危险环境。

二、氢气浓度传感器应用钢厂电池系统变压器维护氢气报警器氢气的探测领域三、氢气浓度传感器地位氢气由于其燃烧效率高、产物无污染等优点,与太阳能、核能一起被称为三大新能源。

作为一种新能源,氢气在航空、动力等领域得到广泛的应用;同时,氢气作为一种还原性气体和载气,在化工、电子、医疗、金属冶炼,特别在军事国防领域有着极为重要的应用价值。

英国阿尔法Alphasense光离子PID传感器PID-AH(小量程)

PID-AH 光离子传感器
PI遮挡直径 3.5mm 处 2. 在 6.2 和 9mm 之间密封 3. 管脚定义： PIN1：输入 PIN2：信号输出 PIN3：地 4.所有的尺寸误差在 ±0.1mm
性能
目标气体最小检测值线性范围最大量程灵敏度稳定时间预热时间零点电压响应时间
PID-LP 10.6 PID-ES PID-CK PID-RT PID-SP
深圳市深国安电子科技有限公司
地址：广东省深圳市龙华新区牛栏前大厦Ｃ５０７蒋小姐：１３４２８７６２６３１电话：８６７５５－８５２５８９００网址：ｗｗｗ．ｓｉｎｇｏａｎ．ｃｏｍｗｗｗ．ｓｉｎｇｏａｎ．ｃｏｍ．ｃｎｗｗｗ．ｓｈｅｎｇｕｏａｎ．ｃｏｍ
-40ºC to +55ºC 0°C to 40°C 在 20°C 时的 95% to 100%；-20°C 在 20°C 时的 125% 0 to 95% 零点附近
5 年（不含灯泡和电极盖） IECEx Ex ia IIC T4; ATEX Ex ia II 1G -40ºC < Ta < +55ºC (< 10VDC 电源) 过滤灰尘和液体用户可更换
电气
功耗供电输出最大信号
工作环境
温度范围温度依赖湿度范围湿度灵敏度
关键参数
预期寿命 IS 认证板载过滤器灯泡配件
底视图
侧视图
5.输入选择孔： A）当用有焊锡填满的时候，内部 LDO 废除，输入需要 3.0 - 3.6 V B）当没有焊锡填满的时候，内部 LDO 生效，输入可以是 3.6 - 10 V 如果供电需要是 10 - 19 V，请跟 Alphasense 联系。
PID-AH 性能数据

氢气浓度传感器原理

氢气浓度传感器原理
氢气浓度传感器是一种测量环境中氢气浓度的传感器。

其工作原理是基于氢气对一定材料的电学或热学特性的影响。

一般来说，氢气浓度传感器包括传感元件和电路板两部分。

传感元件通常采用化学敏感材料，如金属氧化物、半导体等，这些材料可以吸附氢气并改变电学或热学性质。

当氢气浓度变化时，传感元件上的电学或热学特性也会相应地改变，这个变化会通过电路板传递出去，最终转换成数字信号。

氢气浓度传感器的精度、响应速度、灵敏度等性能取决于所采用的传感元件和电路设计。

传感元件的选择需要兼顾灵敏度和选择性，以避免误判和干扰。

电路设计包括了信号放大、滤波等内容，可以优化传感器的性能。

氢气浓度传感器应用广泛，包括氢能源领域、石油化工、航空航天、消防安全等。

随着氢能应用的不断推广，氢气浓度传感器也将成为关键的监测设备。

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alphasense有毒气体电路设计

Alphasense应用笔记AAN105-03 设计恒电位电路介绍：在三电极传感器中，每个电极都有特殊的用途：●工作电极：对目标气体做出反应，氧化或还原目标气体，产生与气体浓度成比例的电流。

该电流必须通过反向电极提供给传感器。

●参考电极：恒电位电路使用该电极保持工作电极处于固定的电位。

对于无偏差电压传感器，工作电极电位必须保持与参考电极电位相同，而对于需要偏差电压的传感器就要有一个偏移量。

●反向电极：反向电极与工作电极构成电路。

如果工作电极正处于氧化反应，反向电极就还原某种化学物质（通常为氧气），如果工作电极正在还原目标气体，反向电极就起氧化反应。

反向电极的电位允许浮动，有时随气体浓度增加而变化。

反向电极的电位不重要，只要恒电位电路能提供充足的电压和电流，保持工作电极的电位与参与电极的电位相同即可。

图1是偏差电压为0的恒电位电路的电路图。

在下面的讨论中请参考本图。

图1典型的恒电位电路由三个部分组成：1.带偏差电压的控制电路（如需要）2.电流测量电路3.当电源关断时，短路FET使工作电极与参考电极相连控制电路控制工作放大器（图1中的IC2）向反向电极提供电流，来平衡工作电极所需电流。

IC2的反向输入连到参考电极，一定不要从参考电极汲取任何大电流。

我们建议使用输入偏差电流小于5nA的工作放大器。

当电路接通电源时，损耗方式JFET（图1中的Q1）转到高阻抗状态。

IC2提供电流，保持工作电极的电流与参考电极的电位相同。

IC2输入偏差电压的任何偏移量将会引起通电时电位的突变。

因为，有毒气体传感器电容大，大电流可通过而只引起小的电位变化，这样确保工作放大器的电压偏移量小，确保小于1mV，最好小于100μV；同时要检查在最高使用温度时的工作放大器偏移电压。

一般，对于可氧化气体（例如CO），（参考电极为铂时）反向电极相对于地电位为-300到-400mv。

然后，如果被还原的是氢离子，而不是氧分子，那么该电位就大到-1.05v。

Unisense氢气传感器用户手册说明书

HYDROGEN SENSOR USER MANUALH ydrogen sensor user manual Copyright © 2021· Unisense A/S Version May 2021HYDROGEN SENSOR USER MANUALUNISENSE A/STABLE OF CONTENTS1: WARRANTY AND LIABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52: CONGRATULATIONS WITH YOUR NEW PRODUCT! . . . . . . . . . . . . . . . . . . . . . . . . . .6 2:1 S upport, ordering, and contact information63: OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84: GETTING STARTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 4:1 u npacking a new SenSor9 4:2 p olarization9 4:3 c onnecting the microSenSor9 4:4 p re-polarization10 4:5 c alibration10 Zero hydrogen reading 10 Hydrogen reading 105: MEASUREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 5:1 m ounting of the SenSorS13 5:2 e lectrical noiSe13 5:3 i nterference14 6: ADVANCED USE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 7: STORAGE AND MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 7:1 c leaning the SenSor168: REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179: TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 41: WARRANTY AND LIABILITY1:1 n otice to p urchaSerThis product is for research use only . Not for use in human diagnostic ortherapeutic procedures .1:2 w arningMicrosensors have very pointed tips and must be handled with care toavoid personal injury and only by trained personnel .Unisense A/S recommends users to attend instruction courses to ensureproper use of the products .1:3 w arranty and l iabilityThe Hydrogen sensor is covered by a 90 days limited warranty .Microsensors are a consumables . Unisense will only replacedysfunctional sensors if they have been tested according with theinstructions in the manual within 14 days of receipt of the sensor(s) .The warranty does not include repair or replacement necessitated byaccident, neglect, misuse, unauthorized repair, or modification of theproduct . In no event will Unisense A/S be liable for any direct, indirect,consequential or incidental damages, including lost profits, or for anyclaim by any third party, arising out of the use, the results of use, or theinability to use this product .Unisense mechanical and electronic laboratory instruments mustonly be used under normal laboratory conditions in a dry and cleanenvironment . Unisense assumes no liability for damages on laboratoryinstruments due to unintended field use or exposure to dust, humidityor corrosive environments .1:4 r epair or a djuStmentSensors and electrodes cannot be repaired . Equipment that is notcovered by the warranty will, if possible, be repaired by Unisense A/Swith appropriate charges paid by the customer . In case of return ofequipment please contact us for return authorization .For further information please see the document General Terms of Saleand Delivery of Unisense A/S as well as the manuals for the respectiveproducts .52: CONGRATULATIONS WITH YOUR NEW PRODUCT!2:1 s upport, ordering, and contact informationThe Hydrogen microsensor is a miniturized sensor for measuringpartial pressure of H2in the micromolar range .If you wish to order additional products or if you encounter anyproblems and need scientific/technical assistance, please do nothesitate to contact our sales and support team . We will respond toyour inquiry within one working day .E-mail:******************Unisense A/STueager 1DK-8200 Aarhus N, DenmarkTel: +45 8944 9500Fax: +45 8944 9549Further documentation and support is available at our websitewww .unisense .com .REPLACEMENT OF SENSORSUnisense will replace sensors that have been damaged during shipment provided that:• The sensors were tested immediately upon receipt in accordance with the delivery note and the manual• The seal is still intact.• The sensors are returned to Unisense for inspection within two weeks.• The sensors are correctly packed for return to Unisense, in accordance with the note included in the sensor box.6673: OVERVIEWThis manual covers all the Unisense H2 and H2-X sensors . For a complete list of sensors sizes and types please go towww .unisense .com .The standard hydrogen sensor type, the H2-type, is for use in environments where H2S is not expected to occur . The H2S insensitive type, the H2-X-type, has an H2S trap in front of the H2 sensing part, allowing the sensor to be used in H2S containing environments (see “5:3 Interference”) .The Unisense hydrogen microsensor is designed for research applications within physiology, biotechnology, environmental sciences, and related areas .With the minute tip size, excellent response time, and good sensitivity the Unisense hydrogen sensor facilitates reliable and fast measurements with a high spatial resolution .The H2-X sensor has a slightly longer response time than the corresponding H2 sensor .The Unisense hydrogen microsensor is a miniaturizedClark-type hydrogen sensor with an internal reference electrode and a sensing anode . The sensor must be connected to a high-sensitivity picoammeter where the anode is polarized against the internal reference . Driven by the external partial pressure, hydrogen from the environment will pass through the sensor tip membrane and will be oxidized at the platinum anode surface . The picoammeter converts the resulting oxidation current to a signal .Schematic view of a hydrogen sensorwith a LEMO plug.IMPORTANT Unisense sensorsare neitherintended nor approved for use inhumans84: GETTING STARTEDThe H2-type and H2-X-type sensors are used in the same way . Only the sensitivity to H2S and the response time differ between the two types of hydrogen sensors .4:1 u npacking a new sensorWhen receiving a new microsensor remove the shock-absorbing grey plastic net .4:2 p olarizationThe signal from the hydrogen sensor is generated in picoampere . Therefore the hydrogen sensor must be connected to a polarizing picoammeter (e .g . a UniAmp series amplifier) .The anode of the hydrogen sensors should be polarized at +100 mV relative to the cathode . This happens automatically on the Unisense UniAmp series instruments . On the Unisense Multimeter, Monometer and PA-2000 instruments this must be set manually . Please consult the relevant the instrument manual for how to adjust polarization . If you are using a PA2000, please check the polarization voltage before connecting the sensor, since incorrect polarization may destroy the sensor .4:3 c onnecting tHe microsensorInsert the connector into a pA input terminal on the amplifier . The connector contains connections for both internal reference electrode and sensing anode .WARNING Do not remove the seal and protectiveplastic tube before these stepsand calibrationare succesfullycompleted.WARNINGIncorrect polarization may destroy the sensorNOTE The conversionof sensor signal in pA to amplifiersignal in mV is controlled by thePre-Amp Range (mV/pA) setting on the amplifer (notPA-2000)94:4 p re-polarizationJust after connecting the sensor, the signal will be very high and unstable then drop rapidly over the first few minutes . After that the signal will drop slowly for up to 1 hour . Therefore, a periodof polarization is necessary before you can use the sensor . This is called the pre-polarization period .The signal should stabilize at 0-10 picoampere (on the PA2000, the sign will be negative since sensor is positively polarized) forzero hydrogen concentration, depending on the specific sensor .If the sensor is new or has not been operated for several days, it must be polarized for at least 1 hour before it can be calibrated and used . After shorter periods without polarization, the sensor should be polarized until it has exhibited a stable signal for 10 minutes .The signal depends on the specific sensor type (see the value in the specifications that came with the sensor) .If the signal does not stabilize or is too high or too low, refer to the ‘Trouble-shooting’ section of this manual .4:5 c alibrationThe calibration procedure is the same for the H2 and H2-X sensors . Calibration must be performed after the sensor signal has stabilized during pre-polarization .z ero hydrogen readingPlace/keep the sensor tip in water and read the signal . This signal is your calibration value for zero hydrogen conditions .h ydrogen readingThe hydrogen sensor responds linearly and consequently atwo-point calibration is sufficient . Prepare water with a defined hydrogen concentration, which is slightly above the maximum expected concentration to be measured . A defined hydrogen concentration can be obtained by 2 different procedures:IMPORTANT Hydrogen sensorsare sensitive to temperature andsalinity,IMPORTANT Calibration must be performed after pre-polarization when the sensorsignal hasstabilized.Always usea calibration solution with the same temperature and salinity as the sample solution.101 . Use a gas mixture controller to obtain a defined mixture ofhydrogen and hydrogen free inert gas from a gas tank (e .g .N2) as bulk carrier gas . For instance, to obtain a hydrogenconcentration of 40,25 µM in the calibration chamber at 20°C, bubble the water in the calibration chamber vigorously witha gas mixture containing a 95 % N2 and 5 % H2 . The hydrogenpartial pressure is in this case 0 .05 atm, and the Solubility is 805 μmol/L/atm . Multiplying the solubility with the partialpressure results in the concentration: 805 µmol/L/atm * 0,05 atm = 40,25 µM .See Table 1 for more values of the solubility, or use the H2calculator in the Unisense SensorTrace Suite software .Start the software, click “Tools” and select “H2 calculator” . .For a Unisense CAL300 calibration chamber,5 minutes of bubbling at a rate of 5 l perminute is sufficient time to achieve 99 % of theconcentration . If the equipment (gas mixturecontroller) is available, this method can beconvenient, as you can switch between differentconstant hydrogen conditions without changingthe water . Use the solubility table (Table 1),or the H2calculator in the SensorTrace software to find the correct mixture at temperatures other than 20°C .To obtain correct concentrations, the headspace above thewater in the calibration chamber must be closed except fora hole only slightly larger than the microsensor shaft . Thiseffectively prevents ambient air from entering the vessel . We recommend the CAL300 Calibration Chamber for calibrations .2 . Add a defined volume of hydrogen-saturated water to adefined volume of water in a calibration chamber . For instance,1 ml of H2saturated water contains 0,805 µmol at 20°C (see Table 1), or the H2 calculator in the SensorTrace software,and to obtain water with a hydrogen concentration of 10 µM,3 .08 ml hydrogen-saturated water should be added to a totalvolume of 246,9 ml hydrogen free water in the calibrationWARNING Vigorous bubbling water with anygas may cause the water to coolconsiderably.Monitor the temperature tofind a suitablebubbling rate,which does notcool the watersignificantly.Calibration chamber CAL300chamber . After the addition of hydrogen-saturated water tothe calibration chamber mix it thoroughly by moving thesensor in its protection tube up and down for a few seconds and read the signal when it is stable . Do not stir bubbles into the water or mix by bubbling, as this will remove hydrogenfrom the water . A magnetic stirrer is not recommended asa mixing tool as a magnetic stirring can introduce electricalnoise to the signal . The hydrogen in the water will slowlyescape to the atmosphere and the concentration can only be considered constant for a few minutes .Hydrogen sensors respond linearly in the range of 0 to 100 %) and signals can be hydrogen (Low Range sensor from 0 - 10% H2linearly converted to partial pressure .Check and repeat calibration at appropriate intervals to ensure that all measurements can be converted to correct concentrations . When the sensor is new, the appropriate interval may be every2 hours; later it may be 24 hours . To minimize the need for calibrations, keep the sensor polarized between measurements, unless the time between measurements exceeds several days or unless the picoammeter batteries are running out . The membrane permeability of hydrogen microsensors changes with time, so a change in signal of up to 50 % may occur over months .If the sensor functions according to the criteria given in the delivery note, the seal and protective plastic tube can be carefully removed before making measurements.5: MEASUREMENTSThe H2-type sensor should be used in H2S free environments . If H2Sis expected to be present, the H2-X-type sensor should be used .Hydrogen sensors can be used for a wide variety of measurements(see our website for further information www .unisense .com) . Themost common use of hydrogen sensors is for making profiles ine .g . sediment or animal tissue where a high spatial resolution iswanted, or for hydrogen measurements in water samples .5:1 m ounting of tHe sensorsAlthough the Unisense microsensors are made of glass, the tipis flexible and can bend slightly around physical obstacles . Thesensor is thus rather sturdy in the longitudinal direction . However,large obstacles like stones or lateral movements of the sensorwhen the tip is in contact with a solid substrate may cause the tip Array to break .Furthermore, due to the small size of the microsensor tip andto the steepness of gradients in many environments, even adisplacement of the sensor tip of few microns may change itsenvironment .Therefore, we recommend that measurements should beperformed only in a stabilized set-up free of moving or vibratingdevices . We recommend the Unisense lab stand LS and theUnisense micromanipulator MM33 (MM33-2 or MMS) forMicromanipulator laboratory use . For in-situ use, we recommend our in situ stand(IS19) and a micromanipulator .5:2 e lectrical noiseThe signal of the microsensor is very small (10-13 to 10-10 ampere) .Although both the Unisense amplifiers and the UnisenseHydrogen microsensors are very resistant to electrical noise fromthe environment, electrical fields may interfere with the sensorsignal . Therefore, we recommend that unnecessary electrical/mechanical equipment is switched off and the sensor or wires arenot touched during measurements and signal recording .5:3 i nterferenceSulphide in the H2S form may interfere with the H2 measurements . The standard hydrogen sensor, the H2-type, is very sensitive to H2S and other reduced sulphur gases . It should, therefore, not be used in environments where H2S and other reduced sulphur gases are present . The H2-X sensor type is not sensitive to H2S up to 100 µM in solution or 1000 ppm H2S in gas . The H2S trap on the H2-X sensor works by removing protons from the H2S and the ionized formsof sulfide cannot pass through the silicone membrane into the H2 sensing part . Other sulphur gases where protons are less easily removed may still penetrate the silicone membrane . The H2-X sensor may, therefore, still be sensitive to other reduced sulphur gases than H2S . It is recommended to only expose the H2S-X sensor to H2S when needed, to maximize the lifetime of the H2S trap . The H2-X sensor may be made even more resistant to H2S . If you needacustombuiltsensor,*************************6: ADVANCED USEUnisense can construct hydrogen sensors for customer requested applications at additional costs . The most frequently requested construction options are described on our website www .unisense . com .The options include for instance customer specified dimensions, response time, stirring sensitivity, pressure tolerance, range and detection limit . If your specifications for a special hydrogen sensor is not described at our web page please contact sales@unisense . com for further options and prices .6:1 Examples of advanced applications• Consumption/production rates of hydrogen . E .g . during enzyme assays in small samples in Unisense microrespiration chambers MRCh• Measurements of hydrogen under high external pressuree .g . in closed pressurized systems, underwater and deep sea applications• Long-term hydrogen monitoringIfyouhavequestions,*******************************7: STORAGE AND MAINTENANCEStore the sensor in the protective plastic tube used for shipping . The hydrogen microsensor can be stored with the tip exposed to water or air . The room in which the hydrogen microsensor is stored should be dry and not too hot (10-30°C) . If the sensor is used regularly it can be stored polarized .7:1 c leaning tHe sensorDepending on which substance is present on the sensor tip or membrane, the sensor can be cleaned with different solutes .The standard method is to rinse with 96 % ethanol (NOT in the protection tube), then rinse with 0 .01 M HCl and rinse with water . This will remove most substances .Alternatively it is possible to rinse with 0 .1M NaOH, isopropanol or different detergents8: REFERENCES• Revsbech, N . P ., and B . B . Jørgensen . 1986 . Microelectrodes: Their Use in Microbial Ecology, p . 293-352 . In K . C . Marshall (ed .), Advances in Microbial Ecology, vol . 9 . Plenum, New York .• Itoh, T ., et al . 2009 . Molecular Hydrogen Suppresses FcepsilonRI-Mediated Signal Transduction and Prevents Degranulation of Mast Cells . Biochem . Biophys . Res . Commun . 389:651-656 .• Kajiya, M . et al . 2009 . Hydrogen From Intestinal Bacteria Is Protective for Concanavalin A-Induced Hepatitis . Biochemical and Biophysical Research Communications 386:316-321 .• Kajiya, M . et al . 2009 . Hydrogen Mediates Suppression of Colon Inflammation Induced by Dextran Sodium Sulfate . Biochemical and Biophysical Research Communications 386:11-15 .• Vopel, K ., et al . 2008 . Modification of Sediment-Water Solute Exchange by Sediment-Capping Materials: Effects on O2 and PH . Marine and Freshwater Research 59, 1101-1110 .Problem High and drifting signal .Possible cause The sensor tip is broken .Solution Replace the hydrogen microsensor .Problem The signal is very low .Possible cause Damage to internal working electrode .Solution Replace the hydrogen microsensor .Problem Very low sensitivity to H2 and low signal Possible cause 1Bubble in the narrow parts of the sensor,often not visible to naked eyeSolution 1Shake the sensor gently like shaking an oldmercury fever thermometerPossible cause 2Bubble in the sensor tip, not visible to thenaked eyeSolution2Soak the sensor in degassed water for atleast 2 hours . Degas water by boiling it andsubsequently cool it to room temperaturewithout getting air into it .Problem Slow response .Possible cause Insoluble compounds deposited at thesensor tip .Solution Rinse with 96 % ethanol, rinse with 0 .01 MHCl and rinse with water .Problem Unstable signal or the signal fluctuatesif the set-up is touched or equipment isbeing introduced in the medium you aremeasuring in .Possible cause Electrical disturbance of the sensorthrough the tip membrane .Solution Ground the set-up using the bluegrounding cable supplied with theamplifier . Connect the reference plug onthe amplifier (blue plug) with the mediumyou are measuring in .If you encounter other problems and need scientific/technical assistance, please contact **********************************(wewillansweryouwithinoneworkday)Table 1: Equilibrium hydrogen concentrations (µmol/litre) at ambient hydrogen partial pressure of 1 atm. in water as a function of temperature.Ref. Wiesenburg and Guinasso 1979. J.Chem Eng. Data 24(4):356-36021·*****************。

热失控h2传感器原理

热失控h2传感器原理
热失控H2传感器是一种广泛应用于氢气泄漏检测和火灾预警
系统的气体传感器。

它基于热传导原理工作。

传感器的基本结构通常由两个热敏电阻组成，一个作为探头（活性电阻）暴露在气体环境中，另一个用作参考（参考电阻）固定在恒温器中。

当氢气泄漏到探头电阻上时，氢气与空气周围形成了可燃混合物，导致热敏电阻上的温度升高。

热敏电阻的电阻值与温度呈负相关关系，因此当温度升高时，电阻值下降。

通过测量热敏电阻的电阻值变化，可以得知氢气的存在和浓度。

为了排除环境温度的影响，系统还需要一个参考电阻。

它被恒温器保持在恒定的温度下，它的电阻值不会随气体浓度变化而变化。

通过比较探头和参考电阻的电阻值，来确定氢气的存在和浓度。

通过将传感器输出与预设的氢气浓度阈值进行比较，可以触发警报或采取相应的控制措施，以便进行泄漏检测和火灾预警。

Alphasense有毒气体传感器4-20mA变送器用户手册说明书

ALPHASENSE USER MANUAL Page 14-20mA Transmitter for Toxic SensorsUMTOX-1 Issue 41INTRODUCTIONThe Transmitter PCB includes circuitry for a three electrode toxic sensor to convert the µA output signal from the sensor to a 2-wire 4-20mA signal. The transmitter board includes 4 mounting pillars that may be removed if not required.Alphasense 4-20 mA transmitters offer convenience and easy maintenance for toxic sensors:• Transmitters are shipped pre-calibrated for immediate use.• Circuitry includes onboard voltage regulator and uses low power two-wire transmitter systems, allowing the simplest possible wiring format.• Small circuit board size allows smaller sensor housing.• Conformally coated circuit board for environmental protection of circuit.• Low power circuitry with excellent performance means no degradation of sensor performance due to electronics.• Amplification of the sensor signal reduces noise pick-up and RFI/EMI susceptibility. Besides periodic sensor re-calibration, the transmitter electronics require no maintenance throughout the lifetime of the sensor. The sensor can be replaced at the end of the sensor working life. Re-calibration is required when the sensor is changed. See section 6.Please read these instructions to ensure correct installation, use and calibration of your gas sensor/ transmitter.2.1Transmitter SpecificationInput Voltage Required+7.5 to + 35 VDCOutput at zero gas concentration4mA (user adjustable)Output at full-scale20mA (user adjustable)Setability /stability<0.05mA (<0.25% FS)Maximum load @ 20 mA, 24 VDC825 ohms (see note)Supply voltage dependence< ±0.2 % output from +7.5 to +35 VDCConnector 2 pin Molex plug (ref. 22-27-2021)PCB current requirement<100 µAPCB dimensions39mm (dia.) x 19 mm (height)Operating conditions See sensor specificationCalibration (shipped pre-calibrated)multi-turn zero and span potentiometersPower supply protection Diode protection to voltage regulatorNo-power equivalent circuit Electrodes short- circuited via FETUMTOX-1Page 22.2Range/OptionsSensor and transmitter boards are shipped from Alphasense pre-calibrated. You may wish to confirm calibration. Standard available ranges are listed below:Sensor Ordering Code(includes sensor)Full-Scale Gas Concentration(ppm)Gain CO-BF THCO-BF 1000Low CO-BF TLCO-BF 100High H2S-BE THH2S-BE 1000Low H2S-B1THH2S-B1200Low H2S-B1TLH2S-B125High SO2-BF THSO2-BF 100Low SO2-BF TLSO2-BF 20High NO2-B1THNO2-B150High NO2-B1TLNO2-B110High CL2-B1TLCL2-B110HighTable 1Transmitter ordering codeAlthough the sensor and transmitter are pre-calibrated and the ranges are preset, it is possible to change range by adjusting the zero and gain potentiometers, which changes the circuit gain.Different sensors can be fitted to a transmitter board; if the gain is in the same category (low or high), then only re-calibration is necessary. If the sensor gain is different, then contact Alphasense for instructions on how to change range.Nitrogen dioxide and Chlorine (NO 2 and Cl 2) sensors give negative outputs, so Cl 2 and NO 2transmitters (THNO2-B1, TLCL2-B1 and TLNO2-B1) will not accept other sensors (CO,H 2S, SO 2), since they have an additional op amp stage to correct for this inverted output.See section 6.3Set Up3.1Mechanical MountingTransmitters are mounted to your housing using the four pillars pre-mounted to the PCB. Two sets of mounting holes are provided so that the sensor/PCB can be fixed to either the housing top (using the locating holes in the corner of the PCB) or to the base of the housing (using either set of locating holes). Figure 1 below shows mounting hole locations (dimensions are in mm). Figure 2 diagrams the sets of locating holes; normally the outerholes are used for mounting, while the inner e in the same location as the earlier issue of this PCB, allowing backward compatibility with the earlier PCB design.Figure 1. Outer mounting hole locations. Figure 2.Inner and outermounting holes.UMTOX-1 Page 3The pillars are tapped to accept an M3 pan head screw. We recommend a screw length that is at least 8mm to ensure rigid fixing. It is good practice to hold the pillar when screwing into the pillars to stop the pillar from rotating on the PCB. It may be easier to remove the sensor whilst screwing the circuit board pillars to your housing. If you move the pillars, ensure that if mounting to the lid of you housing that you include the washer between the pillar and PCB to ensure correct height of the pillar assembly. See figures 3 and 5.Figure 3. Mounting pillar configuration for .Figure 4. Mounting pillar configuration for attaching to the lid of an enclosure.attaching to the base of an enclosure.Figure 5. Side view of mounting to lid of an enclosure.Figure 6. Side view of mounting to the base of an enclosure.Allow 20 minutes after plugging the sensor back into the board for the output to stabilise.Ensure that the sensor is sealed securely to the top face of your housing. The O-ring supplied with your transmitter sensor should be used to ensure an airtight seal, avoiding any access of toxic or corrosive gases to the circuit board and the housing interior.fitted both sidesUMTOX-1 Page 43.2Connection and WiringPower to the transmitter board is via a Molex 2-pin mini plug (type 22-27-2021: supplied with the transmitter). Connect using a screened, two-core cable to the wires (black is ground, red is positive) by either soldering or using a screw terminal block. Twisted pairs can be used for shorter cable lengths. These leads can be shortened or extended as needed.3.3Power SupplyYour power supply must be between 7.5 and 35 VDC with less than 0.2V ripple.Do not supply mains AC power to this unit: this will destroy the transmitter and void the warranty.The transmitter is protected against incorrect polarity but will not function if you have reversed the power supply wires by connecting the Molex plug incorrectly to the transmitter board socket.When selecting the power supply voltage, you must not exceed the maximum total loop resistance, which includes your measuring resistor used to change the 4-20 mA current into a measured voltage.The transmitter requires a minimum of 7.5 volts to operate; therefore, the maximum potential drop allowed across your sensing resistor and cable is:(power supply voltage) -(7.5V)Assuming full-scale deflection at 20 mA, use Ohm's law to calculate the maximum loop (cable plus sensing resistor) resistance allowed.4Correct Usage and MaintenanceEnsure there is a good gas seal between the sensor and the housing; also if the sample is pumped, then ensure that the flow rate is sufficient. Alternatively, the sample gas can be allowed to diffuse to the front face of the sensor. The table below shows the recommended gas flow rate in standard cubic centimetres per minute (sccm). Higher flow rates may be used, but beware that pulsing flow and higher-pressure drops may lead to more erratic readings.Gas Flow Rate (sccm)CO300 to 500H2S400 to 700SO2400 to 700Cl2, NO2400 to 700Table 2Pumped gas recommended flow ratesThe only maintenance required is changing of the O-ring if it has been exposed to extreme environments for long periods (this O-ring should last the lifetime of the sensor in normal conditions). In addition, if the top dust/oil filter has become badly contaminated then contact Alphasense for replacement dust filter (section 5).UMTOX-1 Page 55Reordering Part NumbersReplacement sensor O-rings and dust/oil filters can be ordered by quoting the part numbers below.Part Number Description033-0002-00Replacement O-ring024-0011-00Self-adhesive dust/oil filterTable 3 Replacement Part Numbering6CalibrationThe 4-20mA transmitter is shipped pre-calibrated to the range shown in Table 1. Periodic re-calibration is required for all gas sensors, especially in safety-critical applications.To Calibrate:1First ensure that the power supply is connected correctly and a tight fitting flow hood is in place.2Ensure that a high quality zero gas source is available (e.g. cylinder of zero air or cleaned and scrubbed compressed air) and a bottle of calibration gas with validated accuracy (see Table 5 below).3Apply zero gas for 10 minutes at the flow rate shown in Table 2. Using a small screwdriver, adjust the zero potentiometer (RP2) until the reading is 4.00 ±0.05 mA.See figure 1, attached to this manual.4Apply test gas for ten minutes; the recommended test gas concentration for calibration is shown below in Table 4. Adjust the span potentiometer (RP1) with a small screwdriver until the reading is within ± 0.05 mA of the Span Calibration Point shown in Table 4 if you are using the recommended concentration.5Although it should not be necessary, it is good practice to recheck the zero after setting the span to ensure that the output is still 4.00 ± 0.05 mA in clean air ("zero gas"). Allow at least 10 minutes for full recovery to zero after the calibration gas has been removed.Transmitter Full-Scale(ppm)Calibration gas(ppm)Span Cal Point(mA)THCO-BF100040010.40TLCO-BF10010020.00THH2S-BE100040010.40THH2S-B120050 8.00TLH2S-B1252016.80THSO2-BF1005012.00TLSO2-BF201012.00THNO2-B1502512.00TLNO2-B110512.00TLCL2-B110512.00 Table 4 4-20 mA Transmitter Span CalibrationUMTOX-1 Page 67WarrantyTransmitters are warranted for two years. Sensors are warranted separately. If you have any difficulties or problems then contact:Customer SupportAlphasense LimitedOak Industrial ParkGreat DunmowEssex CM6 1XN, UKTel: +44 (0) 1371 878048Fax: + 44 (0) 1371 878066email:**********************8 AttachmentsFigure 7Circuit diagram@ Alphasense Limited 4 - 20mA Iss 4αlphasense Ltd3 Oak Industrial Park, Chelmsford Road, Great Dunmow, Essex, CM6 1XNTel:+44(0)1371 87 80 48 Fax: +44(0)1371 87 80 66 e-mail : ******************** web: 。

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