Calibrate the pressure sensor on a FieldLab

Calibrate the pressure sensor on a FieldLab

Do-it-yourself instructions for calibrating a Ralston digital gauge with the free FieldLab Desktop software. At the end of this process, FieldLab Desktop will automatically make any necessary adjustments to bring your FieldLab to acceptable tolerances.

This article applies to the following devices:
  1. FieldLab Digital Pressure Calibrator, all models.
  2. Field Gauge, all models equipped with one or more pressure sensors.
Instructions in this article are specific to FieldLab, but also apply to Field Gauge models.


Things you will need:
  1. A PC running Windows.
  2. FieldLab Desktop software version 1.38.0 (or later) installed on your PC. Download the latest version for free.
  3. A Ralston Instruments FieldLab.
  4. USB Cord, provided with your FieldLab.
  5. A pressure source that can generate enough pressure to take the FieldLab and reference to full span.
  6. A reference pressure device that is (recommended) 4 times more accurate than the FieldLab, and has a full span that is equal to or greater than the full span of the FieldLab.


1. Connect the FieldLab and reference gauge to the same pressure source.

2. Power on the FieldLab.

3. Connect FieldLab to a PC running FieldLab Desktop with the provided USB cord.

4. In FieldLab Desktop on your PC, select the FieldLab you want to calibrate from the Devices screen.
You cannot select the FieldLab unless it is powered on and connected to your PC with the provided USB cord.

5. On the FieldLab Overview Screen, select the tab titled "Sensors".

Select the tab titled Sensors


6. On the Sensors screen, select the button titled "Calibration".



7. Select the pressure engineering units you want to use for the calibration process.




Note: The example screens in this support article were taken from a FieldLab model with a full span of 300 psi.
Ralston FieldLab models are available with full spans from 30 to 10,000 psi; so when you are calibrating your FieldLab be sure to follow the actual Min, Mid, and Max calibration points displayed on your computer screen in FieldLab desktop.

8. Adjust the pressure source to the target pressure.
FieldLab Desktop will automatically feed the pressure reading from the FieldLab via the USB connection to Fieldlab Desktop. FieldLab Desktop cannot see the reading on the reference device, so you will need to adjust the pressure so that the reference device displays each target pressure.

If you can't get the reference device to read exactly the target pressure get it as close as you can and then manually enter the reference device reading into the Reference Reading field using your keyboard.

9. When the reading on the reference device indicates you have reached the target pressure, select the "Log Reading" button.




10. Select the button titled “Up Next, Mid Point” to proceed to the next reference point.



Repeat steps 8, 9, and 10 above for each of the remaining reference points.

11. Once you have logged the Min, Mid, and Max Points, select the Make Adjustments button.
After you select the Make Adjustments button, FieldLab Desktop will recalibrate the FieldLab if it is out of spec.

Select the Make Adjustments button once you have logged the Min, Mid, and Max points.


12. Set the Next Calibration Date


13. Save Changes so that the next calibration date will be recorded on your FieldLab and in FieldLab Desktop.

14. Select Exit to return to the overview screen for your FieldLab.


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