229-L散热矩阵电位传感器

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1. If several 229-L probes begin returning very low positive and negative values for dT, what might be the cause?

   Very low values for dT, especially negative values, indicate that the 229-L sensor is not heating during the measurement time. The most likely causes are damage to the heater wires, one or more loose wires, or a failure of the constant current excitation module.

   The first check to make is of the heater wire itself. With an ohmmeter, measure the resistance between the black and green wires on the 229-L. The resistance should read approximately 33 to 36 ohm. An off-scale or infinite reading indicates a break in the heater wire. A low reading could indicate a short in the heater wire. In both of those cases, the fix would be to dig up the sensor wire and examine it for damage.

   The next check is to make sure that there are good electrical connections in the following locations:

   • where the black and green sensor wires connect to the constant current interface or to a multiplexer
   • 多路复用器公共电线连接到恒定电流接口
   • where the constant current interface connects to the data logger 12V, G, and control port

   Each of those wires should have approximately a quarter inch of bare copper securely connected to its terminal.

   Finally, the CE4 or CE8 constant-current module can be checked with a multimeter to make sure it is putting out 50 mA. Measure the voltage between the 12V and ground terminal screws to make sure that the constant current module is receiving power from the data logger. Next, temporarily move the wire connecting the data logger control port with the CTRL channel to a 5 V channel on the data logger to force the module to be on all the time, so that the current output can be measured. Set the multimeter to measure milliamps, and measure the current. It should be 50 mA ± 1 mA. If the current output is outside that range, the constant current module needs to be repaired or replaced.

2. 使用与CR1000的229-L，是否可以对系统进行编程以在激发矩阵电位测量之前读取平衡土壤温度？

   是的。坎贝尔科学建议在打开加热器之前测量和记录传感器的温度。该读数可以用作土壤温度读数。只要矩阵电位测量的频率不比每15分钟更频繁，传感器中就不会有明显的热量堆积，并且传感器温度将与土壤温度相同。

3. 如何从229-L获得读数？

   For details and sample programs,请参阅该部分的“示例程序”部分229-L manual.

4. What is the 229-L heating element made of? In an acidic environment, such as copper mine tailings, would the sensor be expected to fail because of corrosion within five years?

   The heating element is made of Evanohm wire. The element is encased in epoxy inside a stainless-steel hypodermic needle and is not exposed to the corrosive environment. Therefore, that part of the sensor should not fail in five years. However, the sensor cable and the ceramic matrix might suffer damage after being exposed to a corrosive environment for five years.

5. 229-L的校准可用吗？

   目前，Campbell Scientific不为229-L提供校准服务。有些公司提供这项服务。有关详细信息，请联系Campbell Scientific。

6. 坎贝尔科学传感器可用哪些不同的电缆长度选择？

   Most Campbell Scientific sensors are available as an –L, which indicates a user-specified cable length. If a sensor is listed as an –LX model (where “X” is some other character), that sensor’s cable has a user-specified length, but it terminates with a specific connector for a unique system:

   • –LC模型具有用户指定的电缆长度，可连接到ET107，CS110或已退休METDATA1。
   • An –LQ model has a user-specified cable length for connection to a RAWS-P weather station.

   If a sensor does not have an –L or other –LX designation after the main model number, the sensor has a set cable length. The cable length is listed at the end of the Description field in the product’s Ordering information. For example, the 034B-ET model has a description of “Met One Wind Set for ET Station, 67 inch Cable.” Products with a set cable length terminate, as a default, with pigtails.

   If a cable terminates with a special connector for a unique system, the end of the model number designates which system. For example, the 034B-ET model designates the sensor as a 034B for an ET107 system.

   • –ET模型终止于ET107气象站的连接器终止。
   • –ETM型号终止于ET107气象站的连接器终止，但它们还包括特殊的系统安装，在购买替换零件时通常很方便。
   • –QD models terminate with the connector for a RAWS-F Quick Deployment Station.
   • –PW models terminate with the connector for a PWENC or pre-wired system.
7. 特定传感器列出了可用的电缆终止选项？

   Not every sensor has different cable termination options. The options available for a particular sensor can be checked by looking in two places in the Ordering information area of the sensor product page:

   • 型号
   • Cable Termination Options list

   If a sensor is offered in an –ET, –ETM, –LC, –LQ, or –QD version, that option’s availability is reflected in the sensor model number. For example, the 034B is offered as the 034B-ET, 034B-ETM, 034B-LC, 034B-LQ, and 034B-QD.

   All of the other cable termination options, if available, are listed on the Ordering information area of the sensor product page under “Cable Termination Options.” For example, the 034B-L Wind Set is offered with the –CWS, –PT, and –PW options, as shown in the Ordering information area of the 034B-L product page.

   Note:As newer products are added to our inventory, typically, we will list multiple cable termination options under a single sensor model rather than creating multiple model numbers. For example, the HC2S3-L has a –C cable termination option for connecting it to a CS110 instead of offering an HC2S3-LC model.

8. 坎贝尔科学传感器可用哪些不同的电缆终止选项？

   Many Campbell Scientific sensors are available with different cable termination options. These options include the following:

   • The –PT (–PT w/Tinned Wires) option is the default option and does not display on the product line as the other options do. The cable terminates in pigtails that connect directly to a data logger.
   • 在–C（–C W/ET/CS110连接器）选项中，该电缆终止在连接到CS110电场表或Et系列气象站的连接器中。
   • In the –CWS (–CWS w/CWS900 Connector) option, the cable terminates in a connector that attaches to a CWS900-series interface. Connection to a CWS900-series interface allows the sensor to be used in a wireless sensor network.
   • In the –PW (–PW w/Pre-Wire Connector) option, the cable terminates in a connector that attaches to a prewired enclosure.
   • In the –RQ (–RQ w/RAWS Connector) option, the cable terminates in a connector that attaches to a RAWS-P Permanent Remote Automated Weather Station.

   Note:的效果ability of cable termination options varies by sensor. For example, sensors may have none, two, or several options to choose from. If a desired option is not listed for a specific sensor, contact Campbell Scientific for assistance.

9. How can the 229-L be calibrated?

   For details, see the "Calibration" section of the229-L manual.

10. Do heater resistance values of 37 to 48 ohm indicate a problem with the 229-L, or are those values within the normal range?

    加热器电线本身应读取约33欧姆以进行电阻，但是连接到加热器电线的绿色和黑色电线也将增加对读数的阻力。传感器电缆越长，电阻读数的越大。因此，读数为37至48欧姆，在正常范围内。无穷大或少于33欧姆的阻力读数将是由传感器电缆中的断裂或短路引起的，这会引起人们的关注。