Thermo Scientific APEX 100 User Manual page 237

Example of Changing the Polarity for an Output Device
To continue our example from the section above, having moved your reject device to
Output 4, you now want to change its polarity from positive (+) to negative (–).
1) Navigate to the "+4" icon in the outputs menu.
Output 4 Polarity
2) Press the Go button and the icon changes to "–4," indicating the polarity of Output 4
in now negative (–).
Output 4 Polarity
3) Press the Back button to save your changes and exit the menu.
Thermo Scientific APEX User's Guide Page 237