Calibrating Pressure Transmitters

Will you keep the bleedin' NOISE down! I don't take kindly to being woken up at this time in the morning! <Cough, wheeze>

May be you are new to forum, but convension here is CAPITAL letters means barking (shouting). So use small letters next time.

Your question is not clear for answering. Whats cell range and whats calibration range.

Normally, the cell can servive 3 times the working pressure for most of the manufacturers.

sorry for capital letters.

I want to know in what basis we choose the transmitter cell and calibration rang?

for example I have data sheet of PT for which Maximum pressure is 89 bar g and the cell rang is 0 ÷ 400 bar g calibration is 0 ÷ 100?

can any body explain ?

PVSlack has already replied, which I agree., So I need not reply

A good rule of thumb is that the calibrated range should be <= 80% of maximum range. This is to ensure good repeatablity and minimizing overranging (damaging) the instrument.

I do not agree.

The measurement should be done near 80% of calibrated range. In fact the calibration should be done between 20% to 80% of the calibrated range. (Hope there is some standard, where these figures are recommended. Any body may correct these figures, if what I have stated is not correct)

All manufactures assure that the cell will not be damaged even if the maximum pressure reaches Calibrated range X OPR, where OPR is generally 3 or 4.

Not sure what the 89 bar is about. Doesn't sound like something the manufacturer would spec. I can tell you as someone who spent many years developing new product for a pressure sensor manufacturer the transmitter would be spec'd as:

Operating Pressure Range: 0 to 100 bar

Proof Pressure: 300 bar

Burst Pressure 400 bar

If the sensor was spec'd at +/- 1% linearity, then it would be linear within that tolerance over the full operating pressure range between -40C to 125C. Ecspecially if it is a programmable type sensor as most are today, where when the sensors are developed, algorithyms are created for each product line and programmed in that can maintain the sensors' linearity over the entire temperature range.

Older types where thick film trimmable resistors are used to calibrate the circuit and temperature effects could not be adjusted for other than in what materials are used, hence ceramic being very popular, tend to become non-linear towards the upper end of the pressure range on the extreme ends of of the temp range so they were usually sold as +/- 2% to +/- 5% so I would guess that is where that so-called 80% as a good rule of thumb came from.