Calibrate a G2-RAIN


The G2-RAIN’s included rain gauge comes factory calibrated. However, to ensure the most accurate measurements this calibration should be verified regularly.

Note: There are two versions of the G2-RAIN, one with a HyQuest Solutions tipping bucket and the other manufactured by Rickly.

Rickly Tipping Bucket 

G2-RAIN diagram with Rickly tipping bucket

HyQuest Solutions Tipping Bucket

HyQuest solutions tipping bucket

 

Rickly Tipping Bucket Calibration

    1. Remove the siphoning tipping bucket by loosening the three connection bolts and lifting up. Follow the guide below to learn how to remove the siphoning tipping bucket.
      1. Install and Remove the Siphoning Tipping Bucket 

G2-RAIN siphoning tipping bucket

 

    1. Remove the rain gauge from the G2-RAIN-RTU base by unscrewing the (3) 9/16″ bolts.

 

    1. Remove the tipping bucket leads from the reed switch and the other screw holder.

Remove tipping bucket lead from the Reed switch

 

    1. Loosen the cable nut and carefully, one at a time, remove each tipping bucket lead through the cable gasket.
      1. Set the G2-RAIN-RTU aside.

Remove the tipping bucket leads one on top of the other

Carefully remove the leads through the cable gasket

 

    1. Level the gauge using the bulls-eye level

Level the bulls-eye on the rain gauge

 

 

    1. Move the adjustment screw (under the opposite bucket) all the way counter-clockwise.
      1. The bucket over that screw should lie flat.

Rotate the adjustment screw for the opposing bucket counterclockwise

The bucket should lie flat.

 

 

    1. Using a syringe and a mass balance, weigh out the standard amount of water necessary to achieve a tip for the specific tipping bucket model by following the table below.
      1.  While the syringe is empty on the scale, zero the scale to correct for the mass of the syringe, and then add the proper water mass.
Model Number Grams per Tip (g)
G2-RAIN-0.01” 8.40
G2-RAIN-0.1mm 3.31
G2-RAIN-0.2mm 6.62
G2-RAIN-0.5mm 16.54
G2-RAIN-1.0mm 33.08

 

    1. Slowly release water into the raised bucket side.

Slowly fill the raised bucket side with water

 

    1. Once all of the water has been released, slowly spin the adjustment screw (that was lowered in step 4) clockwise until the bucket tips.
      1. This adjustment will force the bucket to tip whenever that specific mass of water is pooled into the bucket.

Rotate the screw below the opposite bucket until the bucket filled with water tips

 

    1. Repeat for the other bucket

 

    1. Confirm the calibration by replacing the outer cover and letting a known amount of water flow through the gauge until 5 tips have occurred for each bucket.
      1. Before beginning the measured test, let several tips occur to ensure the assembly is wet.

 

    1. Measure the output from each bucket separately.

 

Make any necessary changes to the adjustment screws ¼ turn at a time until the expected measurement is achieved

 

HyQuest Solutions Tipping Bucket Calibration 

All HyQuest Solutions gauges are calibrated at the factory; however, HyQuest Solutions does provide products for calibration or calibration checks:

  1. Field Calibration Device (Model FCD)
  2. Laboratory Calibration Unit (Model TB340A)
  3. Recalibration service at HyQuest Solutions’ factory

 

HyQuest Solutions Tipping Bucket Calibration Check 

The HyQuest Solutions Field Calibration Device (FCD) is designed to check tipping bucket calibrations in the field. There are multiple FCD models; however, these FCD’s have all been calibrated to hold a known amount of water, which will be discharged into the tipping bucket, while the user or the data logger records the number of tips.

Follow the Field Calibration Device Manual to perform a calibration check.

  • Using the FCD-314 model (314 mL volume), the following table displays the theoretical number of tips that should occur (+/- 1 tip difference) when performing a field calibration check.
    • Ensure to know the model of your tipping bucket for proper comparison with values in the table.
Theoretical Number of Tips
Bucket Size 200 mm Catch 203 mm Catch
0.2 mm 50.0 48.5
0.5 mm 20.0 19.4
1.0 mm 10.0 9.7
0.01 inch 39.4 38.2

 

  • Using the FCD-653 model (653 mL volume), the following table displays the theoretical number of tips that should occur (+/- 1 tip difference) when performing a field calibration check.
    • Ensure to know the model of your tipping bucket for proper comparison with values in the table.
Theoretical Number of Tips
Bucket Size 200 mm Catch 203 mm Catch
0.2 mm 103.9 100.9
0.5 mm 41.6 40.4
1.0 mm 20.8 20.2
0.01 inch 81.8 79.4

 

 

Please contact either NexSens or HyQuest Solutions for further information.