calibration of transmitter

Calibration of a pressure transmitter

Calibration with analog apparatus

Equipment

Pressure Transmitter range (0 to 200 psig )

Pressure source range (0 to 250 or more than)

Multi meter

24vdc power supply

Procedure

Set range of transmitter to required range (0 to 200 psig)

Connect multi meter in series of power supply to the transmitter

Make graduation of the range of transmitter as follows

(for 0 to 200 psig range)

Applied pressure	Multi meter output	%age
0 psig	4 ma	0%
50 psig	8 ma	25%
100 psig	12 ma	50%
150 psig	16 ma	75%0
200 psig	20 ma	100%

First adjust the zero (with zero screw) that multi meter must read 4ma

If multi meter is reading less then 4 ma then increase the out put by clockwise moving to the zero set screw

And if multi meter is reading more than 4 ma then decrease the out put by moving the anticlockwise to zero set screw

After adjusting the zero apply 50 psig pressure (as u made graduation) to the transmitter where multimeter must show 8ma if not then adjust it from span screw

After adjusting check

100 psig = 12ma.

150 psig = 16ma

200 psig = 20ma respectively

after adjusting all the readings check two or more time to all readings if no changes occur then your transmitter is calibrated

Calibration with HART communicator (Highway addressable remote transducer)

Equipment

Pressure Transmitter range (0 to 300 psig ) “must be Hart enabled”

Pressure source range (0 to 350 or more than)

Hart communicator (275/375)

24vdc power supply

Procedure

Connect the Hart communicator with the transmitter

Connect its terminals across the 250 Ohms resistor connected in series of power supply to the transmitter

When Hart communicator detects your device then go into its setup

Adjust the range through the option lower/upper range value

Set lower range value to zero (0) and upper range value to 300 psig

Set the zero by zero trim option (given pressure must be zero)

Apply 300 psig pressure to the transmitter and set it the 100% range value of transmitter by span trim option

After this setting check the 0 and 100% out put by connecting also multi meter in the series of the power supply

At 0 psig pressure multi meter must read 4ma

Apply the 300 psig where multi meter must read 20ma

Repeat this practice two or three times your transmitter will be calibrated when it matches its output reading match to the input