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In many businesses, knowing what temperature a product has been exposed to and for how long is critical. There should be evidence of temperature and time when sterilizing surgical tools or medical devices in an autoclave or heating food before canning. Temperature monitoring aids facility managers in preventing legionella, while environmental scientists use water temperature to assess the health of rivers and streams. Temperature data loggers can be used to monitor these and other comparable processes, as well as to obtain proof for verification.
The fundamentals of temperature data loggers
A temperature data recorder is a type of data logger that is specifically designed or built to work with temperature probes or sensors (and in the case of a humidity and temperature logger, with humidity sensors too) (and in the case of a humidity and temperature logger, with humidity sensors too). A data logger is an electrical device that can record many measurements. It accepts one or more sensor inputs, sampling and recording the data at a predefined frequency, and is often battery-powered. The logger is recovered at the conclusion of the acquisition time, and the data is downloaded to a PC for analysis. Some data recorders can even send measurement findings to a computer or other device, removing the need for field trips.
Temperature data loggers come in a variety of shapes and sizes.
Every temperature logger is made up of two parts: a temperature sensor or sensors, and a recording device that samples the sensor at specified intervals and records the measurement result. This sensor can be connected to the recording system directly or positioned at a distance.
Sensor on the inside
A tiny, lightweight recording device is created by combining a thermistor or thermocouple with a logger in a single container. Its flaw is that it needs to be placed where the temperature will be measured. Because the electronic elements in the device must operate within a working temperature range, internal sensor loggers cannot be used in high-temperature situations. It does, however, make them helpful for documenting transport temperatures, which may be required for shipping artwork or perishable produce like eggs.
With the help of a thermocouple
Many temperature recorders take one or more thermocouples as direct inputs. OMEGA’s multi-channel HH1384, for example, is a four-channel thermometer and data logger that accepts K, J, E, T, R, S, N, L, U, B, and C type thermocouples. This allows temperature to be recorded near to the thermocouple data recorder, but it is not a good solution when the temperature is too high or low for the batteries and electronics. Many of them are handheld devices designed for recording for a short period of time. Thermocouple and thermistor inputs are available on several general-purpose data recorders, allowing them to be utilized as thermometers.
When using an external probe
Using a temperature data logger with a probe (OMEGA’s OM-CP-HITEMP140-FP is an example of a high-temperature data logger with a flexible probe) solves the problem of obtaining measurements in too hot or cold conditions. This permits the recorder to stay in one location while the sensor is moved to another. It would, for example, enable temperature logging in an oven when the logger itself might perish.
Temperature recorders with several channels
There are general-purpose and temperature data recorders with up to 32 inputs (single-ended—16 differential). Thermistors and thermocouples, as well as 2-, 3-, and 4-wire RTD temperature sensors, will all function with them.
Many data recorders with an inbuilt sensor are designed to look like a USB drive and may be plugged into a computer’s USB port to download data. Other loggers connect through USB, however they require a different cable. Another alternative is to connect the logger to a PC or even a mobile device through Bluetooth®. Some loggers can send data back to a central PC over an Ethernet network, while others use wireless to communicate measurements. Both methods eliminate the need to travel to a data logger in the field to retrieve the information.
Temperature measuring is critical in a variety of applications, from monitoring the health of rivers and streams to ensuring that sterilizing procedures are carried out correctly. In some circumstances, measurements over a lengthy period of time are required to determine long-term trends. Others are interested in knowing the greatest or minimum temperature reached, as well as the time of exposure.
Logging of temperature and humidity
A record of temperature and humidity variation can be valuable in discovering inefficiencies in facility management, especially where precise measurement or temperature-sensitive operations is carried out. In plant and animal propagation, the same is true. The protection against legionella, which can cause a potentially lethal form of pneumonia, is a major issue for a facilities manager. A combination of temperature and humidity data recorders give a time-stamped record of the experienced conditions over a long period of time in applications like these.
The transit of artworks is another circumstance when a time-stamped record is useful. In this case, even knowing that your situation is being monitored may be enough to encourage you to take extra precautions!
logging at high temperatures
While there is no strict definition of "high temperature," a recording device designed to withstand temperatures of more than 80°C (176°F) is commonly referred to as a high-temperature logger. Autoclaves, pasteurization, and food and material processing are examples of high-temperature settings. One example is food canning. In this case, manufacturers must show that the product has reached the minimal temperature required to kill pathogens such as botulism. Loggers for such situations frequently include a probe to keep the sensitive electronics out of the heat.
Temperature monitoring in the water
Aquariums benefit from water temperature monitoring to guarantee a healthy habitat for their fish, many of which can only survive in a specific temperature range. Scientists use the temperature of rivers and streams as a measure of the health of those ecosystems in a similar way. Both are good uses for a water temperature data logger, but they put different strains on the device.
Because the logger will be easily accessible in an aquarium, there will be less of a need for a large memory capacity, and the data can be recovered by direct PC connection or Bluetooth. Obtaining good data regarding river temperatures, on the other hand, may necessitate leaving the logger in situ for several months. Memory capacity, battery life, and even wireless capabilities all become more important in such situations.
Chain of Custody
To avoid deterioration, many foods and drugs must be shipped under tightly controlled circumstances. Incorporating a small temperature data recorder within the carried items to provide a record of the conditions. This helps to assure product integrity and offers documentation in the event of an allegation of mishandling.
Steps to take next
It can be tough to choose the proper temperature data recorder with so many options. The most relevant qualities can only be recognized and the range of available equipment cut down by understanding the reasons for temperature logging. To help with the process, OMEGA Engineering provides an online Data Logger Product Finder tool, but if you still have questions, contact OMEGA’s technical staff for advice on the best equipment for your specific application.