Measuring Range and Display Range for Dial Thermometers
We are often asked what information can be read on the dial of a dial thermometer – apart from the scaling and the serial number. The question often arises as to why some division lines are shaped like a small triangle.
These small triangles serve to mark the measuring range of the thermometer and define the part of the total display range in which the measuring accuracy of the device lies within the error limits defined in standard EN 13190.
Standard EN 13190 also stipulates that the measuring range must cover at least 2/3 of the entire display range. In some cases, however, the measuring range can also cover the entire display range. In this case, identification by the small triangles is omitted.
The permissible error limits within the measuring range vary, depending on the display range and class of the thermometer. Two classes (Class 1 and Class 2) are defined for dial thermometers, each with different error limits. In principle, however, it is also possible to produce other measuring ranges not included in the standard - however, these should comply with the limit values specified in EN 13190.
If the measuring range of the dial thermometer exceeds the display range specified in EN 13190, the error limit of the larger display range applies.
Summarized in brief:
Measuring range: is the range on the dial in which the thermometer measures, within the specified error limits.
Identification of the measuring range: The beginning and end of the measuring range are marked by small triangles.
Standard EN 13190: Is the European standard for dial thermometers and specifies, among other things, the measuring and display ranges as well as the error limits.
Error limits: Vary depending on the class of the thermometer, and are defined within the measuring range.
These markings help the user to recognize in which range the thermometer provides accurate measurements and which ranges are outside the guaranteed accuracy.
