Especially when adding new modules to your AE modular system, it's recommended to check the status of the supply voltage. When too many modules are supplied by one MASTER or POWER module, the supply voltage can drop too low below 5 volts; this can cause some issues like oscillators losing the tracking / calibration, digital modules can show some malfunction and so on.

To make the voltage check convenient, you can use the VOLTAGE TESTER: You can plug it either into a free socket on the bus cable, or via the included adapter, to the extension header at the front / rear side of the case. Then, 5 LEDs show the supply voltage, either green for "ok" (supply voltage is in the range of 4.9 - 5.1 volts), or other colours for too high or too low voltage in steps of 0.1 volts.