I appreciate I may not have answered the question fully as I thought it was just a calibration issue. We've taken a further look into this and the suggestion is to setup a Custom Probe for each of the channels as required in order to scale the values.
The steps to take are as follows:
- Use a 50 Ohm terminator or a short on each channel to measure the offset from 0V in PicoScope.
- Apply the 8V DC input on each channel and measure the voltage.
- Reverse the input to achieve a -8V signal and measure the voltage on each channel - this will help to see if the difference is the same at the positive and negative end.
- Subtract the offset from your readings for each channel if it is 1mV or above.
- If you have obtained negative readings, you can average the magnitude with the positive readings to obtain an average reading.
- If your reading is outside 1% of the range, then you will need to scale the value.
- Divide the average reading by 8V to obtain your scale value.
- Next within PicoScope, click on the Channel options icon for the channel you need to scale, in our case it was Channel B.
- Next click the '...' icon next to the Probe drop-down menu.
- In the Custom Probes window, click 'New Probe...'
- Click 'Next >' when the Custom Probe Wizard appears.
- Leave the 'Probe Output Units' as volts.
- In the Scaling Method dialog, enter your scaling value (m) and offset as required.
- Click 'Next >' and 'Next >' again on the Range Management dialog.
- Enable the Filter as required and click 'Enter', then click 'Next >'.
- In the Custom Probe Identification dialog, enter a name for the Custom Probe and a short description.
- Click Finish.
- A new probe will appear in the Library.
- Select the probe and click 'OK' to begin using it.
- Repeat for the other channel as necessary.
I have attached an example Custom probe that I created which scales the value to 99%. You can use the Import function in the Custom Probes dialog to load this into PicoScope.
Hope this provides suitable clarification.