How to select correct temperature sensor?


#1

Temperature Measurement

How to select a Temperature sensor

** Performance Consideration**

1.Determine the range of temperature to be measured.

2.Identify the operating media that is being measured.

3.Determine the temperature accuracy (+ or - Degree ,+ or - % of reading)

4.Determine frequency response required.

5.Identify the temperature units you require

Fahrenheit
Celsius
Kelvin
Rankine
Reaumure

6.Determine over-temperature conditions?
Will temperature ever exceed maximum of range?
By how much?

Mechanical Consideration

1.Physical Size

Size constraints
Probe length
Location access

2.Process connection/pressure fitting

What is the maximum working pressure of the system?

  1. Characteristics of the media

Corrosive
Viscosity
Velocity
On/Off cycling

Electrical Consideration

1.Analog

mV /V
0-5 Vdc,0-10 Vdc,other
Bipolar voltage
Isolated or Non-isolated voltage
4-20 ma Current

2.Digital

RS485
RS232

3.Combination

Analog and Digital

4.Electrical Termination

Connector or integral cable
Customer specified
Need for mating connectors and cable assemblies
Connector / Cable orientation
Wiring codes / Pin-outs

5.External Zero and Span

6.Specify the type of power supply

Environmental Condition

1.Operating Temperature Range

2.EMI/RFI conditions

3.IP or NEMA rating required

4.Hazardous environment

Intrinsic safe
Explosion proof

5.Indoor or Outdoor use

Exposure to the element
Dust dirt
Temperature extreme
Animal,critters,rodents etc.

6.Submersible or Subsea

Depth
Case pressure

Special requirement

  1. Calibration requirement

2.Special approval / Certifications

3.Testing or Cleaning

4.Special Labeling requirement

5.Shock and Vibration resistance

  1. Serviceability

How accessible must the unit be?
How often will it be serviced?

how to select temperature measuring sensor