Pressure Transducer

Too complex to address in one, or even a few, thread postings.

First, get yourself a standard reference for pressure, we call it Dead Weights : Ametek has various calibration equipment.

It does not only stop there. You need to check or calibrate transmitter output and receiving module io's by a signal calibrator(below)

Then you will have a reliable instruments, frequency of calibration has guidelines depending on your QA/QC protocols and mandate

A1) See #2 above.

A2) Transducers don't have SOPs _{(no apostrophe as it is a plural)}. SOPs are there to provide ways of operating the entire plant. An SOP might conceivably cover the situation where a transducer is out-of-service for whatever reason, and that is all. If the question is about calibration procedures, then it depends upon the equipment in use to carry out the calibration, an example of which is given in #2 above. The procedure itself will be given as a guidance note in the operating manual for the equipment.

For further information, discuss the matter with the Instrument Technician that normally carries out the task at the facility.

You find, "How pressure transducers are caliberated" by first learning How to Search the Internet - Hannon Library.

It's so easy, even a child can do it.

Calibration of a pressure transducer

High quality transducers will generally produce a linear output. If you plot it on a graph, it looks like a straight line whose formula is Y=mX + b where "b" is the Y value when X=0 or the cross over point.

Most of the little meters that you might use have instructions for how to enter the b value. If it were a scale, you might call this the TARE setting.

As a mechanical engineer you should know more about transducers since modern machine design can only go ahead with measuring thus using transducers.

1- What is a pressure transducer? If is a device which gives an information proportional to the actuating pressure. This can be an optical information on a dial or an electric signal which can be processed. In most cases the sensing element is a "mechanical" part which presents a deformation under pressure effect, this deformation is measured either mechanical (manometer with a bourdon tube + gears) or electrically (strain gauges, LVDT,aso) and displayed either optically (dial) or as an electric signal (voltage or current).

2- What is calibration? The transducer indications have to be "correct" as image of the pressure so that the device has to be checked and adjusted for the rightness of the supplied information.

3- How is a transducer calibrated? There basically 2 different ways to calibrate

a- one generates a pressure applying a dead weight on a piston sliding without friction in a cylinder and compares pressure value with displayed signal.

b- one generates a pressure and measures it with 2 devices at same time one being the device to be calibrated and the second a reference device which was already calibrated usually by the method "a". This is a calibration by "comparison" which has a lower degree of uncertainty but acceptable in most industrial applications.

If you consider electric or electronic devices then the whole chain from sensor to display has to be "calibrated" and not only the sensor.

This is calibration in mini nutshell.

You MUST consider what was written above very seriously: take a good book about instruments and measuring techniques since the future of your "mechanical" professional life is more and more connected to this technique.

The calibration procedure used depends on what type of pressure transducer is being calibrated.

Contact the Original Equipment Manufacturer to obtain the correct procedure(s) and to identify the correct equipment required to perform the procedure.

In today's "black box" technical world it may well be that the device in question cannot be calibrated in the field or it may be a "throw away" one-time-use device that cannot be re-calibrated at all.

Keep in mind that the more accurate the device is, the more accurate and more expensive the calibration equipment used will be.

Any/all calibration equipment must be regularly sent to the OEM or other certified testing and calibration facility for calibration and certification.

Hope this helps.