Instrument’s Definition
Are you familiar with the basic definition’s for the Instruments ? Let us learn primary definitions in this article today for the instruments. We all get use to the instruments in our daily life from general stores to Industry. In Industry we discuss our requirement for the instrument to our supplier or manufacturer. Let us have glance on the primary definitions.
1) Reading
Any value shown by the instrument is know as Reading value.
2) Instrument Error
Result of a Instrument measurement value minus a standard value (True Value) is known as Instrument Error.
Error = Reading – True Value
3) Accuracy
Ability of the instrument to measure the value as close as to true value. Accuracy is usually represented in % value. The more closeness to % value to zero (0%), more accurate is the instrument.
4) Rangeability
It is defined as a ratio of maximum value to minimum value a instrument can measure.
5) Turndown ratios is the ratio of the maximum value to minimum value of the measuring range.
Note : There is minor difference in rangeability and turndown ratio. Rangeability specify ratio of complete range of instrument, however turndown specify ratio of the measuring range of instrument.
6) Operating Conditions
The set of process conditions from lower values to upper range values under which the instrument will operate and performance of meter will occur.
7) Measuring range of Instrument
The range of measuring value of the instrument. It is defined by lower and upper range limit that define the measuring span.
8) Calibration range of Instrument
The range of measuring value of the instrument for which the instrument is intended to lie within guaranteed specified limits.
9) Calibration
Calibration can be defined in many ways.
For Instrument World :- Calibration is set of process of determine the error of the instrument by comparing the reading shown by the instrument against standard value (true value) under specified condition.
In General, we can say calibration is the process of adjusting the instrument or equipment to customer’s specification.
10) Hazardous Area
Hazardous area is defined in DSEAR (Dangerous Substances and Explosive Atmospheres Regulations) as “any place in which explosive atmosphere can occur in quantities and is require to have special precautions to protect the safety of workers.
11) Ingress Protection (IP)
Ingress Protection rating, is an international standard (IEC 60529) used to rate the degree of protection or sealing effectiveness in electrical enclosures against intrusion of objects, water, dust or accidental contact
12) Temperature Classification
Temperature Classification is a term that is allocated within a hazardous area or zone to instruments and equipment. The classification or rating signifies the levels of thermal energy allowed in a particular area or produced by specific equipment.
