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MAS2600: Testing and Recalibration Reference Manual
December 2014 Ed 21
41
Recalibrating the Absolute Transmitter using Pressure on
the Transducer
Caution! Please observe that testing and recalibration of transmitters mounted in hazardous
areas shall be carried out by Ex qualified personnel.
When recalibrating the MAS2600 Absolute Transmitter a pressure calibrator with a range of
-1 to 3.5 bar should be used. It should have an accuracy of 0.05% FS or better, as well as a 4½ digit
milliampmeter. If a calibrator without reference transmitter is used, the atmospheric pressure must
be known to calculate the correction.
Atmospheric pressure and Transducer range to be entered into the formulas as mbar.
1. The calibrator with the output selector switch set to pressure mode is connected to the
MAS2600 transmitter via MAS2600 Test Cup, type G022S100 (DPI610 and DPI603) or type
G022S103 (DPI802P CAL KIT).
2. Check the transducer range. The transducer range is indicated on the amplifier inside the box.
3. Calculate output signal in conditions of no pressure (atmospheric pressure), using below for-
mula. The output signal should be adjusted to the calculated value on the zero potentiometer.
mA at Atmospheric pressure = 4 + (16
*
(Atm. press - 800) / (Trd. range - 800))
4. Calculate the pressure for maximum output signal, using the following formula.
mbarg at 20 mA = Trd. range - Atm. press
Increase the pressure to calculated pressure and adjust the output signal to 20.00 mA on the
span potentiometer.
5. Remove the pressure and check the zero point.
6. Check the linearity at 0-25-50-75 and 100% of the measuring range.
Output signal at different pressures P can be calculated, using the following formula.
mA at P mbarg = 4 + (16
*
(Atm. press - 800 + P) / (Trd. range - 800))
7. If necessary, repeat the steps 3 to 6.
Example:
If the range of the transducer is 3.5 bar abs and the atmospheric pressure is 1005 mbar.
Calculated output at atmospheric pressure:
mA at Atm.press = 4 + (16
*
(1005 - 800) / (3500 - 800)) = 5.215 mA
Calculated applied pressure for maximum output:
mbarg at 20 mA = 3500 - 1005 = 2495 mbarg
Calculated pressure at 50% of the transducer range:
mA at P mbarg = 4 + (16
*
(1005 - 800 + 1750) / (3500 - 800)) = 15.585 mA