Meriam MFT 4010 Modular Calibrator_HART Communicator - Manual (Page 23)

18
FIELD RECALIBRATION
All pressure modules and the integral mA / V meter can be recalibrated in the field for zero, span, and linearity. The
proper primary standards must be available prior to calibrating the MFT or modules. These standards should meet
the accuracy requirements for your company or industry. Meriam follows the guidelines established by ANSI / NCSL
Z540-1-1994 which requires that the primary standard be 4 times more accurate than the unit under test.
For pressure sensor modules up to 200 PSI, Meriam recommends a ±0.0015% of reading deadweight
tester for optimal accuracy. For sensors 200 PSI and above, a ±0.0030% of reading deadweight tester is
recommended. If calibrating using inches of water units, be sure to match the reference temperature of water
in both devices.
The TIO0110 thermocouple module field recalibration supports one (1) point at 0.00 ºC. See the TIO0110
T/C Measure & Simulation section in the Appendix of this manual for more details.
The RIO4000 RTD module field recalibration supports Module Only recalibration using precision resistors
and Module + Probe recalibration using a temperature bath or a dry block temperature tester. See the
RIO4000 Measure & Simulation section in the Appendix of this manual for more details.
The VMA0055 mA / V module does not have field recalibration support. Contact the manufacturer to return
out of tolerance VMA0055 modules for service and recalibration.
To enter Field Recalibration mode from the Measure Mode display, press the More soft key, then press the Rcal
soft key. This will access the Field Recal Setup screen.
Field Recalibration Setup Screen
Module: Select to choose which sensor module (S1, S2, S3) or mA/V (I or V) meter to calibrate.
Units: Allows the user to choose the engineering units to calibrate in. Meriam recommends the calibration be
performed in the default units of the subject sensor. For example: an xDN0200 sensor with a range of 0-200” of
water referenced to 20º Celsius should be calibrated using a deadweight tester with the same units and
temperature reference. Other engineering units or reference temperatures may be used but great care in units
and temperature reference conversion must be used to achieve accurate calibration results.
Points: This option allows the user to select the number of calibration points desired from pressure modules. The
example above would use 3 calibration points; 0%, 50%, and 100% of the full range of the sensor. The user may
select 3, 5, or 9 point calibrations if desired for pressure modules. (See Appendix topics TIO0110, RIO4000, and
VMA0055 for more details on using Rcal feature to field recalibration these modules).
Start: Begins the recalibration process.
Restore Defaults: Restores factory calibration coefficients for use
Recalibration Set-Up Menu
Select the parameters desired and the sensor module to be calibrated using the options provided. Press the Up
or Down soft keys to scroll to the desired parameter. Press the Select soft key to choose that parameter. A
sub-menu opens showing the options for the selected parameter. Use the Up or Down soft keys to scroll to the
Field Recal
Field Recal Setup:
Start
Module: 1
Units: inW20C
Points: 3
Restore Defaults
Up Down Select Back