Using the Load Cell

Use this set of instructions when working with the load cell and PanelX software.

Download the software from the HBM web page. You will also need to download the driver for the RS485 to USB adapter from NI.

Connecting the load cell to PanelX

1. Connect the USB cable to a Windows computer.

2. Turn on the power supply (the black box) and wait a few seconds.

3. Start the PanelX program; a "Device scan" window will open automatically. 

4. Check the box next to RS232/RS485.

5. Make sure the Baud rate is set to 38400. 

6. Click Scan. 
   

   
   
   

7. When the scan has finished, the number and the sensor information will appear. 
   If the number of devices is zero, then you must perform the scan again or check if there are any problems with the connections of the load cell.
   
   

   
   
   

8. Close the window by clicking OK. 

9. Your display should now look something like this.
   

   
   
   

Begin Working with PanelX

1. Go to the top menu and click on Options.

2. On the Options menu go to User level.

3. Select the Administrator user level so that all the menu items are available.

Application:

1. Go to the Application tab. 

2. Select Checkweigher. This is used in industrial applications and I didn’t notice any change in the measurements when using standard or checkweigher. Use the one you like.

Adjustments:

Before working with the load cell, certain adjustments are necessary.

1. Click on the Adjustment menu icon: 
   

2. Select the decimal point configuration to: *******. This setting will display a number in this form: XX. 
   

   
   To make it have one decimal point, click on the x10 icon.
   
   
   
   A number in this form should appear on the measurement window: XX.X 
   
   
   
   

3. Choose the measuring unit. (i.e. “g” ). 

4. In this decimal configuration, the highest resolution is of 1g. Therefore, select 1 g in the Resolution drop down menu. 

5. Set the nominal value to 20000 g. This is supposed to be the range of the measurements you are performing; however, the load cell only displays correct data when the nominal value is set to 20000 g. 
   
   Your configuration should look like this:
   
   

   
   
   

6.  Click on Write.

Filters

Filters are used to cut off certain frequencies and prevent the program from displaying noise. 
The filters used for dynamic weighing are the 1: FIR32, 3: IIR4 (fast track), 4: FIR64, and 5: FIR64 filters.

1. Go to the Filter tab.
   

    
    

2. Select the filter that most suits you.  
   Recommended settings:
   
   

    
   
   

3. Click on Write.
   
   More on filters: 

   The 3rd filter : IIR4 (fast track) provided stable values with little noise - almost constant lines with a 0.1 g variation. Be careful when setting the cutoff frequency because if you choose a small cutoff frequency, you lower the sensitivity of the load cell. You will obtain a slow reaction time if cutoff frequency is 0.1 Hz. Try using 1.5 Hz; this will give faster reaction times. If you don’t observe changes in your experiments, then try elevating the cutoff frequency so that the load cell becomes more sensitive to change.

   You might want to play with filters and their cutoff frequencies to see which one is most suitable to your experiment; just remember which filters are the ones recommended for dynamic weighing and the effect of elevating or reducing cutoff frequencies.