What's the difference between a data viewer and a chart recorder?

Data Viewers and Chart Recorders are two different types of temperature monitors. Chart recorders are mechanical instruments that use a pen to draw a line on a paper chart that indicates the temperature record over some period of time. Charts can cover a day, a week or even a month but must be changed when the time is up or the next days data will overwrite the previous temperature data. Many people are moving to electronic devices such as data viewers to eliminate the ongoing expense of charts and pens, not to mention the constant need for maintenance to insure that the chart recorder is operating properly. Data Viewers are all-electronic Data Viewers such as the ThermaViewer completely eliminate the need for charts, pens or maintenance. They collect temperature data through sensors, which they store electronically in RAM memory. The better ones also draw a chart on an LCD so that the user can see what has been going on with the temperature. The ThermaViewer eliminates the need for maintenance. The ThermaViewer can store and display ten months of temperature data from each of its two sensors on the LCD display. The user can see enough temperature history so that trends are obvious. These all electronic devices also have built in relays to trigger an alarm or auto dialer if the temperature strays outside of user set parameters. Temperature monitors are extremely important for many industries. Many industries need temperature monitors to comply with regulations and for safety reasons. For example, laboratories and hospitals must monitor refrigerators and freezers where they have medicine, vaccines, or tissue samples stores. In these cases it is not only important to monitor the temperature to comply with government regulations but it is critical that the viability of the vaccine be maintained. If the vaccines get too warm they lose their effectiveness and won't perform their proper functions.