How to resolve a possible software bug on the Labrador.
Update August 1, 2021
I’ve noticed that the “Paused” check box appears to “delete the buffer and force a reload”. For example, I might see some clipping on a sine wave and if I check/uncheck Paused, the wave will appear accurately. This would help explain why “checking and unchecking Paused” can fix a multitude of sins. Therefore my new advice is, if your results aren’t what you expect, do the following:
- Ensure your power supply setting is high enough (+1.6V above expected signal) to cover the expected results. This is very important when measuring an AC signal such as a sine wave.
- Make sure you are able to see the signal:
- If you don’t see a signal at all, press M or Oscilloscope -> Show Range Dialog on Main Page and adjust Vmax such that you can see a signal.
- Ensure your screen is showing a good signal and the signal is not a flat signal with no noise.
- Checking (Clicking) and unchecking Paused on Oscilloscope CH1 can frequently change a flat signal to a good signal.
- Make sure Trigger is unchecked if you are measuring a AC signal such as a sine wave.
If you continue to have problems with the Multimeter, remember:
- Oscilloscope CH1 and CH2 are the probes for the DMM.
- Voltage measurements are a differential measurement, which means you are measuring the difference between CH1 and CH2.
- Ensure both CH1 and CH2 signals show on the screen then use the vertical cursors to measure the difference between the two signals.
I have found that this method can be extremely accurate.
There appears to be a bug in the software for the Multimeter function. When attempting to measure voltage using the Labrador Multimeter, you might see this issue:
- Multimeter will show approximately 3V for any voltage above 3V
- Or if measuring a voltage that goes negative, the range will be limited to +3V and -3V
If You Prefer the Solution in Video Form
Illustration and Solution to Bug in Long Form
Confirm Bug Exists: Hardware
- Plug Oscilloscope CH1 (Orange wire) into measure the positive socket on the Labrador
- Use Oscilloscope CH2 (Blue wire) into the ground socket on the Labrador
- Plugin Labrador to USB on computer and start the Labrador application
Confirm Bug Exists: Application
In the Labrador Application
- Start the Labrador application
- Immediately Uncheck Oscilloscope CH1 box
- Check Multimeter box
If the bug exists, the Multimeter will show approximately 3.01V and it needs to show approximately 4.5V (Note all 4 values Max/Min/Mean/RMS are exactly the same)
Three Step Fix In the Labrador Application
- Uncheck Multimeter and check both Oscilloscope channels then press M to bring up Range Dialog and enter 5V for Vmax (remaining values don’t matter)
- Check and Uncheck Paused under Oscilloscope CH1
- Uncheck Oscilloscope CH1 and CH2 and check Multimeter and the values will be accurate