Compare contact type and non-contact type speed measurement method.
Contact type method
|
Non contact type method
|
Physical contact between meter and shaft
|
No Physical contact between meterand shaft
|
Consists of moving parts
|
Does not consist of moving parts
|
Output is electrical signal
|
Output has to be converted to electrical signal
|
Optical transducer is not used
|
Optical transducer is used
|
ADC is required
|
ADC is not required
|
Maintenance is more due to the moving parts
|
Maintenance is less
|
Ex.AC / DC tachometer
|
Ex. Rotary Encoder, Photo electric tachometer
|