A well-engineered, universal product range for an extremely wide range of applications in process automation: tecsis manufactures in its own plants – in the most internationally powerful locations. This is the guarantee of top class quality and maximum flexibility in all areas of measuring technology.
Piezoresistive sensor elements contain a silicon chip with a pressure sensitive diaphragm, which comprises the resistors of the measuring bridge.
The sensitive silicon chip is isolated from the process medium by means of a stainless steel diaphragm.
The pressure inside the capsule is transmitted to the wafer by a special transmission fluid.
Thin Film Sensors
Thin film sensors are made of stainless steel with the resistors of the measuring bridge (Wheatstone Bridge) manufactured on the surface of the membrane (thin film technology).
The measuring resistors are located in the area of compression and expansion of the membrane.
The base body of the ceramic cell is made of ceramic and the resistors are printed on the membrane (thick fiilm technology).
For both the ceramic and the thin film cells the measuring diaphragm is simultaneously the separating diaphragm.
An internal transmission fluid is not required.
Membrane Pressure Switches
The membrane transmits the pressure of the medium to the switch contact.
Piston Pressure Switches
The piston with O-ring sealing transmits the pressure of the medium to the switch contact.
Transistor Outputs p-switching (pnp)
The load is connected to the switching output with the GND as reference point.
Transistor Outputs n-switching (npn)
The load is connected to the switching output with the supply voltage as reference point.
The Hall Measuring Principle
If a magnetic field is present that is perpendicular to the direction of current in a conductor, the electrons experience a force, called Lorentz force.
This Lorentz force causes electromigration that can be measured as hall voltage.
The hall effect is used to measure the deflection of resilient measuring elements. Therefore the magnet is fixed on a membrane or a bourdon tube.
The hall sensor transforms the pressure proportional signal into a switching signal. The switch point is adjusted by moving the hall sensor by means of an adjustment screw.
Programmable Electronic Pressure Switch
The programmable electronic pressure switch is based on a measuring sensor with bridge circuit.
The bridge signal, that depends on the pressure, is evaluated by the microcontroller (µC) and controls the switching transistors.The switching points can be adjusted with the programming buttons on the instrument.
Normally close (NC): contact opens if p > pswitch
Normally open (NO): contact closes if p > pswitch
Changeover contact (SPDT): contact 1 opens and contact 2 closes if p > pswitch
Switch Points and Maximum Pressure
The contact changes its status (it opens, closes or changes) as soon as the pressure reaches the switching point (see also switching functions). The hysteresis determines the reset point.
The switching point can be adjusted within the adjustment range. The adjustment range must be selected so that both the switching point and the reset point are within the adjustment range. If several pressure and switching cycles are taking place, the switch point will be within specified repeatability.
Pressure switches can be loaded dynamically up to the maximum working pressure. Furthermore sporadic and short pressure peaks up to the overload limit do not damage the switch. If the system pressure exceeds the burst pressure the pressure switch might be destroyed and will leak.