Calibrating a Digilent Test & Measurement Device

While all Digilent Test & Measurement devices are factory calibrated, they can be recalibrated so that you can ensure that you are making the most accurate measurements possible.


Inventory


Guide

1. Device Manager

In the Settings menu in the bar at the top of the WaveForms window, click on Device Manager to open the device manager window.

Once the Device manager window opens, you can explore all of the features of the device manager.

In the top half of the window, the table contains the devices that you can use with WaveForms. If you have a device plugged in, it will appear here.

Along with the devices that are plugged in, you can also see a DEMO mode for each Digilent Test & Measurement device supported by WaveForms.

Demo modes allow you to see all of the features of WaveForms as if you had plugged that device in. For example, with the Demo Discovery selected, if you open the oscilloscope tool, you can see channel 1 and 2 scoping a square and sine wave.

Plug in your device so that is shows up in the device manager. If it is the only device connected, it will be the only entry in the table with a serial number.

Device manager window.


2. Rename Tool

The first tool to explore is the rename tool. In the device manager, click on “Rename” at the top left of the screen. Here you can type in a new name for your device. You can use uppercase or lowercase alphanumeric characters.

Our new device.

For example, we named ours “MyDevice”.

The Rename tool can be useful if you have more than one device or are collaborating in a large group where there will be multiple devices present.

Device renamed.


3. Calibration Window

Next, we are going to explore the calibration feature to ensure the best possible accuracy for captured data.

In the Device Manager window, click “Calibrate”. This will open the Device Calibration window.

The first tab you will see in the calibration window is the “Calibrate” tab. Here you can see all of the tools that can be calibrated.

There is also the “File” menu where you can save or load an existing calibration file, and the “Reset” menu, which we will talk about later.

The Parameters and References tabs can also be seen. These are the values that define the existing calibration. It is highly recommended that you do NOT manually change these values. Instead, we will do a full calibration using the Calibration Wizard.

Calibrate tab.


5. Device Calibration Wizard

To open the Device Calibration Wizard, click “Wizard” at the top of the Device Calibration Window.

When the wizard opens, the start screen appears, as in the figure to the right, which tells you what you will need in order to calibrate your device. Click Next.


6. Calibrate Waveform Generator 1

The first thing you'll need to do calibrate is the first waveform generator. To do this, connect the waveform generator 1 pin to your digital multimeter.

Connect the yellow wire (positive end of the waveform generator 1) from the flywire assembly to the positive side of your multimeter. Connect the negative side of the multimeter to a black wire (ground) from the flywire assembly.

Circuit set up.

Read the value on the multimeter. As indicated by the Calibration Wizard, it should be around 0.

Enter the value you read off of the multimeter into the Calibration Wizard, and click Next.

Repeat this process until the Calibration Wizard indicates to move on to waveform generator 2 (10 total measurements).

Note: Default values in the “Measured” field indicate the expected result of the measurement.

Enter calibration value.

0.987—

7. Calibrate Waveform Generator 2

Create the same circuit as before, using waveform generator 2 instead of waveform generator 1. To do this, swap out the waveform generator 1 pin (yellow cable) with the waveform generator 2 pin (yellow cable with white stripes).

Plug in waveform generator 2.

Read the value on the DMM, it should be around 0. Enter this value into the Calibration Wizard and hit Next.

Repeat this procedure until the Calibration Wizard indicates to move on to Oscilloscope Calibration (10 total measurements).

Enter value.


8. Zero the Oscilloscope

The next step in the calibration process is to zero the oscilloscope.

As indicated by the Calibration window, connect all of the oscilloscope probes to ground.

To do this, connect the positive end of channel 1 (orange cable), positive end of channel 2 (blue cable), negative end of channel 1 (orange cable with white stripes), negative end of channel 2 (blue cable with white stripes), and the ground (black cable).

Setting up the circuit, close up.

Click Next to start the calibration.

The oscilloscope zero calibration is automatic, so all you have to do is wait for it to finish (this may take several minutes).


9. Calibrate the Oscilloscope

The calibration we will do next will be for the oscilloscope. The first step is to set up the circuit.

Connect the positive ends of the 2 channels of the oscilloscope to waveform generator 1 (blue and orange cables), and the negative ends of the 2 channels of the oscilloscope to ground (blue and orange cables with white stripes).

Circuit setup, close up view.

Click Next to start the oscilloscope calibration. This is another automatic calibration, so you'll just need to wait for it to finish (this may take several minutes).


10. Calibrate the Positive Power Supply

The last things to calibrate are the variable power supplies, starting with the positive one.

Connect the positive supply (red cable) to the positive probe of the DMM. Connect a ground pin (black cable) to the negative probe of the DMM.

Connect positive supply and ground to DMM.

Read the value off of the DMM and enter it into the text field. As indicated by the Calibration Wizard, it should be around 1. Click Next.

Continue taking and entering voltage readings until the Calibration Wizard indicates to move on to the negative power supply (two total measurements).


11. Connect the Negative Supply

Disconnect the positive supply (red cable) and replace it with the negative supply (white cable).

Repeat the same process used on the positive supply until the calibration window indicates that the negative supply has been calibrated (two total measurements).

Connect the negative supply.


12. Finished!

To complete the calibration, click Finish.


13. Apply the Changes

In the Device Calibration window, click Apply, then Yes in the popup, to confirm the changes.


14. Compare Accuracy

We've hooked up the device's flywires so that the waveform generator 1 is connected to channel 1 of the oscilloscope.

In the image to the right you can see captures of the datalogger reading the 0 value with and without calibration. You can see that with calibration, the zero is more accurate.

Compare the accuracy.


15. If Necessary, Reset Calibration

If you are ever dissatisfied with the calibration of your device, you can reset the calibration to factory settings, or reset all values to zero by using the Reset menu in the Device Calibration window.


16. Use Your Digilent Test and Measurement Device

Now that you've gone through the calibration process, you can begin taking advantage of the many features of your Test & Measurement device.

To read more about those features, you can view your device's reference manual, accessible via the device's resource center, linked from this wiki's Instrumentation page.

There is also an extensive collection of projects on the Digilent Learn Site, as well as an entire curriculum called Real Analog written for the original Analog Discovery, but adaptable to the Analog Discovery 2 or Analog Discovery Studio.