DSC2000 Calibration – Load Cell

Overview

1)   It is recommended that Transducer Calibration is carried out by qualified personnel at a periodic interval defined by the local Standards.

2)   The recommended method for Dual Point Calibration is to use a certified Reference Device that is at least as accurate as the resolution required for the Transducer to be calibrated.

3)   This Support Document covers dual point calibration in CLISP Studio for Load Cell’s connected to a DSC 2000M for dynamic triaxial testing and a DSC 2000MM for Dynamic simple shear or Dynamic triaxials with dynamic cell pressure control.

4)   It is assumed that:

-          CLISP Studio is running

-          The DSC to which the Transducer is connected has been added in CLISP Studio

-          The DSC 2000 is communicating with Clisp Studio

Calibrating a Load Cell

To start the calibration processes open the DSC 2000 Instrument Window in Clisp Studio and select the Analogue Inputs Tab

Figure 1 - DSC Instrument Window in Clisp Studio

Important

When calibrating a Load Cell it is very important that the correct units are used. The transducer units must be set to kN in Clisp Studio.

To edit the calibration setup it may be required that you press the Edit button and enter the passcode 2603.

Figure 2 – Vertical Load Panel

Calibration Initial Setup

Now add the zero and FSD. The Zero is normally 0 and the FSD is the maximum Load that the Cell can read. In most cases this is 5kN. This can be found on the Calibration certificate supplied with the transducer.

Figure 3 - Calibration Certificate

Lastly make sure Dual Point is selected. Single factor calibrations cannot be used with the DSC 2000. Once this has been completed press the ‘Write’ button (see Figure 4).

Figure 4 - Writing the FSD

There are two ways the calibration can be completed either by using the calibration certificate or using a reference device. If you are using a calibration certificate please read section 5 and if you are using a reference device please read section 6­­­.

Calibration using the Calibration Certificate

In Clisp Studio open the advanced tab, the first number we need to enter is the Raw Divisions at Full Scale

Figure 5 - Raw Divisions at Full Scale

This number can be calculated from a value that is found on the calibration certificate; the number required is the sensitivity, as is highlighted in figure 3.

This number must be put through the following calculation:

So from the example calibration certificate in figure 3 above you would get the following answer:

2.1821 / 1000 = 0.0021821

So the following would be entered into the raw divisions at full scale. Once this has been entered press the write button.

Figure 6 - Calculated Raw Divisions at Full Scale

To complete the Raw divisions at Zero ensure that the transducer is at is zero load. Then press the Zero button.

Figure 7 - Raw Divisions at Zero

Calibration using Reference Device

A Reference Load Cell with attached display unit is used for calibrating Load Cells.

Figure 8 - Reference Load Cell

1)     Set up the Instrument with the Reference Load Cell in place below. Figure 9 shows a Frame with the Reference Load Cell in Place.

NOTE: the example shown below is for an Internal (submersible) Load Cell.

Figure 9 - Example Triaxial Frame Internal Load Cell Calibration Setup

2)     From the ‘Inputs’ screen of the Instrument that the Transducer is connected to, click on the Load Channel Number to display the Channel setup window (see Figure 1). In order to enable editing of the Calibration Parameters, the ‘Edit’ button should be selected and the passcode entered.

3)     Select the ‘Dual Point’ radio button, set the ‘Zero’ field to the lowest Load reading (usually 0) and the ‘FSD’ (Full Scale Deflection) field to the highest Load reading (in this example 5kN).

4)     To reset the Load Channel calibration, click on the ‘Clear’ button.

5)     To send the input information to the Transducer, click on the ‘Write’ button.

6)     With zero Load being applied, click on the ‘Zero’ button. The Display will reset to 0.

7)     Now apply Load using the Instrument until the Reference Cell readout displays the Maximum Load then click on the ‘Gain’ button. The Display will reset to the FSD value (in this case 5.000kN – see Figure 10). When different loads are applied, the Display will reflect the load accordingly.

Figure 10 - Load Calibration Screen