| With worldwide concern about global climate change | | | | triggering a pulse from a reed switch to measure 0.2 |
| the use of data logger equipment to monitor a wide | | | | of a millimeter of rainfall. A data logger must have a |
| range of environmental factors such as temperature, | | | | pulse input to work with a rain gauge. |
| solar radiation, rainfall, and water table levels is | | | | Data Logger Inputs for Solar Radiation Sensors |
| becoming increasingly prevalent. | | | | Whilst many low cost data logger models can work |
| Many modern data logger models offer long | | | | with temperature sensors and rain gauges, the very |
| operation on internal batteries coupled with multi | | | | low voltage output of solar radiation sensors can |
| channel universal input capability. This makes them | | | | present a problem. With a typical range of 0-20 mV |
| ideal for use in the field with a variety of | | | | to represent a range of 0-2000 WM2 a data logger |
| environmental sensors. The basic data logger inputs | | | | needs a very low measurement range and high |
| required for these sensors are listed below: | | | | resolution to take meaningful readings. |
| Data Logger Temperature Sensor Inputs | | | | Data Logger inputs for Water Level Sensors |
| The three main types of temperature sensors are | | | | Water level sensors are usually submersible pressure |
| thermocouples, PT100 sensors and thermistors. | | | | sensor types or ultrasonic non contact. As most |
| Thermocouples require a data logger with high | | | | pressure based depth sensors require excitation the |
| resolution and cold junction compensation. | | | | data logger needs to be able to power the sensor. |
| Thermocouples do not require external power making | | | | Many data logger models have a five volt supply |
| them ideal for use with data logger installations in | | | | available for this type of sensor. For use with |
| remote locations. Thermistors are low cost and | | | | ultrasonic level sensors the data logger needs to be |
| accurate, but are non linear so the data logger needs | | | | able to power a 4-20mA loop. |
| an internal look up table to read these devices | | | | Data Logger Inputs for Wind Sensors |
| accurately. PT100 sensors are very accurate, but as | | | | These are available with voltage, mA and serial |
| they are three wire devices many low cost data | | | | outputs. Whilst most data logger types can handle |
| logger models are not compatible. | | | | voltage and current inputs few are able to read serial |
| Data Logger Rain Gauge Inputs | | | | devices. The new generation of Omni Instruments |
| A rain gauge is a barrel shaped device with a rain | | | | data logger models support the serial protocols used |
| collector. The collector funnels the rain water onto a | | | | by the latest wind sensors. |
| tipping bucket sensor. When the bucket fills up it tips, | | | | |