In this section we will read about
- Current to pressure Converter (I/P Converter)
- Control Valve positioner or Pneumatic positioner
- Parts of a pneumatic control valve positioner
- Control Valve and its types
- Solenoid Valve
- Pneumatic Cylinder
- Butterfly Valve
- Globe Valve or pneumatic globe valve
- Parts of a Control Valve
- Pneumatic globe valve types
- Control Valve Characteristics
- Class of a control valve
- Pressure Transmitter
- pressure transmitter working principle
- Pin type pressure Transmitter
- Pressure Transmitter connections
- pressure transmitter signal checking
- Flow transmitter
Pin type pressure Transmitter
In this lesson, we will study a pin-type pressure transmitter.
Pin-type pressure Transmitter
- Piezo-resistive sensor
- A piezo-resistive sensor has a far more complex structure than the sensors described above. The sensor element is made of a silicon chip. This chip consists of a diaphragm, structured with piezoresistive resistors, which deflects under pressure. The chip has a surface area of only a few square millimeters and is thus much smaller than, for example, the diaphragms of metal thin-film or ceramic thick-film sensors.
- The piezo chip is very susceptible to environmental influences and, therefore, must be hermetically encapsulated in most cases For this reason it is installed into a stainless steel case that is sealed using a thin flush stainless-steel diaphragm. The free volume between the piezo chip and the (external) diaphragm is filled with transmission fluid. Synthetic oil is usually used for this. In an en-capsulated piezo-resistive sensor, the pressure medium is only in contact with the stainless- steel diaphragm, which then transmits the pressure through the oil to the (internal) chip’s diaphragm.
A pin-type pressure transmitter (pin type PT)has standardized interfaces, both on the process side and on the electrical output signal side, and converts the physical pressure value to a standard industrial signal. The pressure connection is used to lead the pressure directly onto the sensor. It has a (standardized) thread and an integrated sealing system to enable easy connection of the pressure transmitter simply by screwing it in at the relevant measuring point. A suitable case protects the sensor and the electronics against environmental influences. The electronics transform a sensor signal into a standardized signal; e.g. the common industrial signal of 4- 20 m Amp. The output signal is transmitted via a (standardized) plug or cable for sub-sequent signal evaluation.
Supply for pin type PT is 24 V DC
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