A form of energy, according to the classification

- Pneumatic instrument: Twenty century Forty It's been widely used in industry.

- Features: simple structure, stable performance, high reliability, low price, the essence of explosion-proof, especially suitable for petroleum and chemical explosion dangerous situations.

- Electric meter:

- Features: electrical signal transmission, amplification, transform processing is relatively easy, easy to realize remote monitoring and operation, easy computer interface, more extensive application.  Take preventive measures, also can be used in flammable and explosive occasions.

- Hydraulic instrument: not widely used.

- Electric control Pneumatic instrument control Comparison of instrument