Fluid Pressure Sensor
DECIPHERICATION OF FLUID PRESSURE SENSOR
Geokon Pressure Transducer Model 4500H link to data sheet
The main function of the pressure transducer is to measure the pressure of a fluid in a hydraulic or pneumatic pressure line.
Operation and Energize
The transducer uses a pressure sensitive diaphragm with a vibrating wire element attached to it. the diaphragm is welded to a capsule which is evacuated and hermetically sealed. Fluid pressure acting upon the outer face of the diaphragm causes deflection of the diaphragm and changes in tension and frequency of the vibrating wire. The changing frequency is sensed and transmitted to the readout device by an electrical coil acting through the walls of the capsule. The transducer is energized by batteries in the readout device.
The output of the device is the changing frequency of the vibrating wire that is attached to the diaphragm.
Standard Ranges: This defines the limits that the transducer input can vary. For this transducer, it can either be as small as 70 kPa and as large as 5 MPa, with other choices in between.
Over Range: The transducer is able to withstand pressures of two times the rated pressure before it breaks.
Resolution: The smallest change in the input value that will produce an observable change in the output is rated at 0.025% of F.S.
Accuracy: The summation of all of the possible errors that can occur is +/- 0.1% F.S.
Linearity: The linear relationship between the pressure reading (input) and the wire frequency (output) can vary up to 0.5% F.S.
Temperature Range: The transducer can be used between the temperatures of -20 degrees C and 80 degrees C.
Thermal Zero Shift: When the temperature changes by 1 degree C the output of the transducer for zero input will change by less than 0.05% of F.S.
Diaphragm Displacement: At F.S., the diaphragm displacement will be less than 0.001 cm cubed. This is the maximum that it will move when pressure is applied.
Length x Diameter x Mass: The sensor's physical dimensions are 140 x 25.4 mm squared and it has a mass of 0.30 kg.
Sensor Interface with Electronics
The pressure transducer is attached to a readout device via a long black cord that can be up to several kilometers in length. This readout device will allow the user to monitor the fluid pressure.
Sensor Interface with Dynamic System
The transducer is supplied with a 1/4-18 NPT male or female pope threading to allow it to be coupled directly into hydraulic or pneumatic lines. Other pipe thread sizes are also available upon request.