Data logger in hospitals

Increasingly, in hospitals data logger technology is becoming indispensable for the monitoring and recording a wide range of parameters.

Data logger use for fridge and freezer monitoring:
A common application for data logger use is in the monitoring of temperature in fridges and freezers used to store drugs and samples. Many drugs must be stored within a narrow temperature band at around 6 degrees C to be kept in useable condition. Prior to the advent of data logger technology hospital staff would have to frequently check the temperature of the fridge with a traditional thermometer. Not only was this inefficient, but also could not guarantee that the temperature had not gone out of limits in between readings. By placing a small temperature data logger inside the fridge, temperature can be recorded continuously. Also the data logger will usually have a warning LED which blinks if there has been a temperature excursion. Because the data logger has a visual alert, staff generally only need to download the data from the logger on a monthly basis, saving valuable time for other activities.

Data logger use in cold stores:
Large walk in cold stores are often used for critical storage of medical supplies. Here a data logger with an SMS text alarm may be used to alert staff out of hours or at weekends if the door has been left open, or if there has been a system failure. The data logger may have an integral GSM modem or an external modem to send the text message.

Data logger use for liquid gas monitoring
A data logger with a very low range temperature probe can be used to monitor liquid nitrogen. Sometimes a dual channel data logger is used to monitor the pressure as well as temperature.

Data logger use in incubators
Incubators are often fitted with a data logger to record temperature an sometimes other parameters such as CO2 and oxygen levels.

Data logger uses in operating theatres
A data logger is often used to monitor temperature and humidity in operating theatres to ensure the comfort of patients and staff.

Data logger applications in medical research
It is not possible within the scope of this article to list all of the applications for data logger technology in medical research, but here is an interesting example:
Recently medical researchers used a data logger fitted with strain gauges to measure the force being applied to an external steel brace on a broken limb. As the bone healed the bending force applied to the brace slowly reduced. The data logger was set to record this force every few seconds so the healing process could be monitored very closely over a period of four weeks, providing invaluable data.

So it can be seen that data logger technology is now used extensively in hospitals to help maintain both the quality and safety of the care that they provide.

Jim Furness is CEO of Omniinstruments Ltd, specialists in data logger and other instrumentation solutions

Temperature data logger

Perhaps the most common application for the use of the data logger in the world today is for temperature logging. The temperature data logger is used in factories, offices, hospitals, museums, road transport, and outdoors for environmental monitoring. Here is an outline of typical temperature data logger applications:

Temperature data logger use in factories
The monitoring and logging of temperature is vital in many manufacturing processes. In the food industry a temperature data logger is often used to ensure that unprocessed food is stored at the correct temperature in cold stores. It is also used in ovens and production lines to ensure the food has been heated to the correct temperature for the required length of time

In the semi conductor industry clean rooms and production processes must be kept at a constant temperature to ensure quality control. Here the temperature data logger is indispensable.

In brick works a temperature data logger is used in the oven through process to ensure that bricks are cured to the correct temperature.

Temperature data logger us in offices
Many companies will position a temperature data logger in main working areas throughout their building to verify that a comfortable temperature is maintained during working hours. Staff will sometimes complain that a room is either too hot, or too cold. A data logger can be used to record the actual temperature so that subjective judgments can be corroborated.

Temperature data logger use in hospitals
Hospitals use many types of data logger for temperature recording. Fridges and freezers where drugs and samples are stored will have a temperature data logger permanently installed. Incubators are also generally monitored for temperature and here a data logger is often used for historical data.

Temperature data logger use in museums and art galleries
In paintings many artefacts are extremely sensitive to temperature. It is common for a temperature data logger to be placed in each room, and often within individual display cases to monitor ambient temperature. In art galleries paintings are very sensitive to temperature. As well as placing a data logger in each room, sometimes a temperature data logger is also fitted within the frame of very old paintings, particularly those painted on wood.

Temperature data logger use in environmental monitoring
In addition to general weather monitoring the temperature data logger is used widely to log temperature over large areas where scientists and researchers need to have exact ground temperature data. Typical examples are glaciers, rain forests, mountain areas, and polar regions. A temperature data logger can also be used to monitor rivers and lakes.

Temperature data logger use in road transport
Sensitive or delicate goods, in particular foodstuffs can often be in transit for many hours or days by road. A data logger can be used to check that goods in refrigerated trucks have been maintained at the correct temperature throughout a journey. In the UK it is now a requirement to use a data logger to record temperature in vehicles used for livestock transportation.

Jim Furness is CEO of Omniinstruments Ltd, specialists in data logger and other instrumentation solutions

What is a Data Logger ?

A data logger is a solid state device used to measure and record analogue and / or digital inputs from sensors or other instruments. Typically these sensors or other instruments will themselves be measuring environmental or process parameters such as temperature, humidity, pressure, flow, level, wind speed, wind direction, and many other physical properties.

A data logger is a stand alone recording device. It does not need a PC to store it’s data. There are many types of data logger. However they fall into two broad categories.

1) Small compact battery powered data logger for use in remote locations or in application where weight and space available is critical

2) Large multi channel data logger, usually mains powered to store large amounts of data from many external sensors and inputs.

Data logger design has improved exponentially over the last few years. A typical small data logger for single channel temperature measurement will be no larger than a matchbox, and can store up to 32,000 temperature readings. Utilising flash memory some 4 and 8 channel data logger types are still small enough to fit in your pocket, with battery life of up to 2 years.

Most types of data logger come with custom software to download data to a PC, show the results in graph and table format, and export data to MS Excel and other applications. The proprietary software is also used to program the data logger for sample rate, and logging duration. Data is usually downloaded directly from the data logger to the PC. However with many types of data logger data download can also be achieved remotely using Ethernet, low power radio, GSM, GPRS or telephone lines. Some data logger models also publish their data direct to websites.

Due to it’s versatility in measurement applications the data logger has become an indispensable tool for academic and medical research, biologists, physicists, process engineers, civil engineers, electrical engineers and environmental scientists. A wide range of data logger types are used across a whole spectrum of industries, including power generation, oil and gas exploration, general manufacturing, civil construction, aerospace, horticultural and medical science.

Omni Instruments has been actively involved in the data logger market for over 10 years and has supplied all data logger types for a vast range of applications. They include:

Temperature data logger – for use in offices, factories and hospitals
Temperature and humidity data logger for measurement in museums and warehouses
Temperature, rainfall, wind speed and direction, solar radiation and barometric pressure data logger for measurement in remote weather stations
Multiple input data logger units for vibration, orientation and movement measurement in robots and remotely controlled vehicles
Process data logger units for pressure, flow and level measurement in factories and plants
Vibration data logger for goods in transit

In short a data logger in many applications is a far more effective means of recording measurements and activity than a man with a clip board or traditional recording instruments such as chart recorders.

Jim Furness is CEO of Omniinstruments Ltd, specialists in data logger and other instrumentation solutions

Data Logger use in environmental monitoring

With worldwide concern about global climate change the use of data logger equipment to monitor a wide range of environmental factors such as temperature, solar radiation, rainfall, and water table levels is becoming increasingly prevalent.

Many modern data logger models offer long operation on internal batteries coupled with multi channel universal input capability. This makes them ideal for use in the field with a variety of environmental sensors. The basic data logger inputs required for these sensors are listed below:

Data Logger Temperature Sensor Inputs
The three main types of temperature sensors are thermocouples, PT100 sensors and thermistors. Thermocouples require a data logger with high resolution and cold junction compensation. Thermocouples do not require external power making them ideal for use with data logger installations in remote locations. Thermistors are low cost and accurate, but are non linear so the data logger needs an internal look up table to read these devices accurately. PT100 sensors are very accurate, but as they are three wire devices many low cost data logger models are not compatible.

Data Logger Rain Gauge Inputs
A rain gauge is a barrel shaped device with a rain collector. The collector funnels the rain water onto a tipping bucket sensor. When the bucket fills up it tips, triggering a pulse from a reed switch to measure 0.2 of a millimeter of rainfall. A data logger must have a pulse input to work with a rain gauge.

Data Logger Inputs for Solar Radiation Sensors
Whilst many low cost data logger models can work with temperature sensors and rain gauges, the very low voltage output of solar radiation sensors can present a problem. With a typical range of 0-20 mV to represent a range of 0-2000 WM2 a data logger needs a very low measurement range and high resolution to take meaningful readings.

Data Logger inputs for Water Level Sensors
Water level sensors are usually submersible pressure sensor types or ultrasonic non contact. As most pressure based depth sensors require excitation the data logger needs to be able to power the sensor. Many data logger models have a five volt supply available for this type of sensor. For use with ultrasonic level sensors the data logger needs to be able to power a 4-20mA loop.

Data Logger Inputs for Wind Sensors
These are available with voltage, mA and serial outputs. Whilst most data logger types can handle voltage and current inputs few are able to read serial devices. The new generation of Omni Instruments data logger models support the serial protocols used by the latest wind sensors.

So it can be seen that for environmental monitoring applications it is important to select a data logger with multi channel input capability which is able to support a wide range of sensor inputs

Omni Instruments has many years of experience of providing data logger equipment for these applications and can also supply compatible sensors.

Jim Furness is CEO of Omniinstruments Ltd, specialists in data logger and other instrumentation solutions

Data Logger Applications – Remote Data Logger Systems

The data logger has now become the indispensable tool for anyone requiring to monitor and record factory processes or environmental conditions automatically. Stand alone data logger systems are now used throughout the manufacturing, chemical, oil and gas, water and power generation industries. Data logger units are also commonly used for industrial R and D, medical research, and environmental monitoring.

However, whilst it is very useful to use a data logger to record a process, or environmental conditions. The data is no use inside the data logger, it has to be downloaded to a PC to be viewed by the relevant users. Typically a user will take a laptop PC to the site and connect directly to the data logger to download the data. This is OK where the site is nearby and data does not need to be downloaded very often, but for remote sites, or where the data logger needs to be downloaded often this is not very practical.

Many types of data logger now incorporate various means of remote communication to enable the data to be collected without a site visit. These can be summarized as follows:

Data logger remote communication via GSM.
The data logger is fitted with a GSM modem so that the host PC can connect over the worldwide GSM network.

Data logger remote communication via GPRS
The data logger is fitted with a GPRS modem and data is transferred via the internet utilizing the worldwide GPRS network

Data logger remote communications via SMS text messaging
The data logger sends it’s data at regular intervals or on alarm via SMS text message. This is ideal for small amounts of data, such a daily totals from water meters, gas meters or electricity meters.

Data logger remote communications via Ethernet
The data logger connects directly via Ethernet TCP/IP to a host PC or network. Some data logger models are also able to publish web pages directly to the internet

Data logger remote communications via low power radio
The data logger connects to the host PC using license free low power radio. Ranges up to 10 KM can be achieved with this method.

Using remote data acquisition solutions such as these OEM manufacturers have the option to monitor equipment for fault conditions almost anywhere in the world. A typical example is of a manufacturer of steel mill equipment based in the UK being able to monitor faults in it’s equipment installed in a mill in China. Where once an engineer would have been sent from the UK to China to investigate a potential fault, now the initial diagnoses and remedial action can be carried out remotely saving time and considerable expense. Portable systems with built in GPRS are now available as turnkey products, with the ability to email logged data direct to a user’s inbox.

Omni Instruments has many years experience in providing remote data logging solutions for both machine and environmental monitoring together with relevant sensors for process measurement and also weather monitoring.

Jim Furness is CEO of Omniinstruments Ltd, specialists in data logger and other instrumentation solutions