Pressure transmitters for relative and absolute pressure

Function: Changing the measured pressure will cause the sensor diaphragm to deflect. This change is converted to a 4-20 mA output signal.

Technical parameters of absolute and relative pressure sensors:

• Type of measured pressure value: Relative, absolute
• Accuracy: <0.5%
• Output type: Analog
• Analog output: 4 - 20 mA
• Supply voltage: 24 VDC
• Connector: Hersman DIN43650
• Housing material: Stainless steel AISI 304
• Membrane material: Stainless steel AISI 316
• Sensor material: Silicon
• Degree of protection IP: IP 65
• Temperature range of the measured medium: –25 ° C ～ +8 5 ° C
• Response time: 10 ms
• Influence of ambient temperature: 0–50 ° C from the upper limit of the range <0.5%, –20 ° C to + 80 ℃ from the upper limit of the range <1%
• Seal: Viton
• Overload capacity: 150% of the measured range
• Suitable for materials compatible with stainless steel AISI 304.

Another option for connecting absolute and relative pressure sensors:

Possibility of delivery with separating clamp membrane made of stainless steel AISI 316L - easy sanitization of the meter.

Use: 

• Light industry
• Medical devices
• Regulation of pressure processes
• Hydraulic and air pressure systems
• Cooling, air conditioning
• Compressors
• Food and beverage industry

Absolute pressure, relative pressure, and differential pressure

Every pressure measurement, even for example a tire pressure measurement, is related to a reference pressure. Usually, the measurement is related to the pressure of the physical atmosphere, other times it is a measurement with respect to an ideal vacuum or to another reference pressure. When measuring pressure, we, therefore, distinguish the following terms:

• Absolute pressure is the pressure measured against an ideal vacuum, absolute pressure is equal to relative pressure plus atmospheric pressure.
• Relative pressure is the pressure measured against atmospheric pressure, so it is equal to the difference between absolute pressure and atmospheric pressure.
• Differential pressure is the pressure difference between two different points.

source: Wikipedia