| a logger is a device for electronically recording | | | | instrument are accurate and adhere to |
| data for a certain time period or in a specific | | | | specifications. There are many laboratories |
| location using either built in instruments or sensors, | | | | throughout the world that specialize in the |
| or instruments and sensors that are externally | | | | calibration and certification of measuring sensors. |
| attached to the device. The electronics are | | | | Calibration is necessary to ensure that the quality |
| generally based on a digital processing chip. The | | | | of the entity being measured conforms to |
| devices are normally small, portable, battery | | | | internationally accepted standards. |
| powered and controlled by a microprocessor. | | | | The pressure sensor used to record the pressure |
| They employ memory chips for storing data and | | | | of liquids or gases generates an electrical signal in |
| sensors for collecting the data. | | | | the transducer. A transducer is a device that |
| Many of these devices can be connected to a | | | | converts energy from one form into another. For |
| personal computer and employ specialized | | | | example the pressure on the transducer is |
| software to access, view and analyze the data | | | | converted to an electrical signal that can be |
| that has been collected. Other types can have | | | | measured. There are various methods for |
| keyboards and LCD screens attached to them to | | | | generating the energy forms such as diaphragms, |
| view the data as a standalone unit. | | | | pistons, Bourdon tubes or bellows which are |
| There are many different types of data logging | | | | activated by the application of force or pressure |
| equipment, ranging from very simple counters in | | | | over an area. The conversions are performed |
| one environment to collecting a large range of | | | | using a variety of sensing technologies such as |
| measurements for specialized applications in a | | | | capacitive, electromagnetic, piezoelectric, |
| constantly changing environment. Many of the | | | | potentiometric and optical. |
| devices are programmable while others take | | | | There are a great number of applications that |
| static measurements and have limited or non | | | | make use of data logging devices. These include |
| changeable parameters. In many applications, | | | | weather stations, the recording of soil moisture, |
| these devices have replaced chart recorders. | | | | road traffic counting, vibration and shock |
| One benefit of these data collectors is that they | | | | monitoring, vehicle testing, scientific |
| can be set to collect data over a 24 hour period | | | | measurements and hundreds more. The modern |
| unattended. They are often activated and left to | | | | data logging device can now be combined with |
| measure and store information over a | | | | wireless technology for transmitting the data to |
| considerable period. This produces an accurate | | | | central collection points. |
| representation of the environment being | | | | Modern data logging devices have now become |
| monitored, such as relative humidity and air | | | | more sophisticated than their earlier counterparts |
| temperature. The humidity sensor measures both | | | | and may now be employed as flight data |
| air temperature and moisture. The percentage of | | | | recorders, event data recorders collecting data |
| relative humidity is the ratio of air borne moisture | | | | before and after an automobile crash, collectors |
| to the highest moisture level that can be held by | | | | of automobile diagnostic codes and countless |
| air at that temperature. | | | | more. The data logger has now become an |
| Anyone who uses a measuring instrument should | | | | integral part of daily life. |
| be confident that the results obtained from the | | | | |