Settings - Voltage
The Voltage section really exists of 3 parts; at the top you have the sensor selection and at the bottom you have the alarm and visual section for the selected sensor. So if you select a new sensor then the Alarm and Visual section will change according to the settings for the selected sensor. This means that you can/must configure each sensor on it's own
Voltage configuration
On some boards you need a special voltage configuration, if your board is in this list then select it, else just go for the standard one
MBM Voltage sensor
MBM 5 can show you up to 7 voltage lines, the one you select here determines to what sensor all the others changes you make on this tab are applied