Meriam MFT 4010 Modular Calibrator_HART Communicator - Manual (Page 106)

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Module Only cal can also be performed using a User Cable (p/n A900028-90500) and a precision
resistor. When the User Cable is connected to the RIO4000, the RIO User Select Screen is displayed.
The user can select the 10 Ω, 100 Ω, or 1000 Ω precision resistor options from the list and proceed as
above.
3.2 Module + Probe method is an alternative for users who need a module and probe reference standard
calibrated as a “matched set;” that is, using a specific RIO4000 module with a dedicated RTD probe
and cable to achieve the best possible displayed accuracy. This method allows adjustments to be
made to the Module + Probe calibration by using an external temperature bath, dry block, Ice Point
Calibration Reference Chamber, or other temperature standard. The user can select 1-, 3-, 5- or 9-
point calibration options. When calibrating using a temperature bath or dry block, a DIN Class A RTD
should be used for best possible “matched set” accuracy.
Please note that 1) all calibrations are executed in °C units and 2) adjustment made to calibration
points within a multipoint calibration procedure are temporarily saved point-by-point but not
permanently saved until the entire procedure is completed. To erase Rcal data, simple select the
“Restore Defaults” option from the Rcal Feature Main Setup Menu shown above.
Selecting the Module + Probe option with an RTD connected will cause the following display to appear
on the MFT.
The
Module + Probe recalibration screen shown above provides the following information:
Cal Point: target calibration temperature expressed in percent of the specified range. The default
Calibration Range is -20
° C to +80° C (see the following section “Other Recalibration Keys and
Functions ” information on changing the range or any point within the range).
Applied: the target recalibration temperature calculated by the MFT based on the number of calibration
points selected in the
Rcal set-up menu for the default or specified range.
S1/S2/S3: this line shows measured temperature in the sensor bay location of the RIO4000 module.
The temperature applied by the user standard is displayed in
°C.
Error: the algebraic difference between the applied temperature and the temperature measured by the
“matched set” (RIO4000 module and connected RTD or RTD simulator) expressed in
°C.
Adjust the temperature source until the temperature applied matches the
Applied value displayed. If the
“matched set” is accurate, the Error value will be very close to zero. If the Error value indicated
exceeds your requirements, press the Adj soft key and enter the actual applied temperature value as
indicated by your standard. Press the Done soft key and then select Yes to save the new data point.
This process adjusts that particular point on the calibration curve. Confirm the Error value is now within
specification (see below).
Field Recal
Cal Point:
0%
Applied: -20.00 C
S1: -20.01 C
Error: -0.01 C
Adj Abort Next Back
Field Recal
Cal Point:
0%
Applied: -20.00 C
S1: -19.54 C
Error:
0.46 C
Adj Abort Next Back
Probe Only Recalibration Screen