Some devices feature a universal power adapter for two-pin industrial connectors, which caters for variable power supply voltages of 10 – 28 volts.
To avoid a failure or damage to the device, these models monitor and the voltage and report over- and undershooting of the allowed voltage range.
The displayed voltage is the actual momentary input voltage at the integrated universal power adapter. The input voltage can have a minimum value of 10 volts and a maximum value of 28 volts. If input voltage over- or undershoots the allowable range, the device reports the error via SNMP trap and as a SYSLOG message. Furthermore, LANmonitor logs these states to the device activity list. In such cases you should quickly ensure that the permissible input voltage is supplied again.