The embodiment of the invention provides an electric meter abnormity switching apparatus comprising a
signal acquiring and comparing unit, a PLC
control unit, and a
relay control unit. The
signal acquiring and comparing unit is connected with an
operating table, is used for acquiring the
voltage and the loop resistance of the
operating table, and respectively compares the
voltage and the loop resistance with a set
voltage threshold value and a set resistance threshold value in order to generate a level
signal, wherein, a high level is outputted if the voltage is over the voltage threshold value or the voltage threshold value is over the set resistance threshold value, otherwise, a low level is outputted. The PLC
control unit is connected with the signal acquiring and comparing unit and outputs a PCL control instruction to the
relay control unit according to the level signal outputted by the signal acquiring and comparing unit. According to the PCL control instruction, the
relay control unit controls the disconnection and the connection of the relay. The electric meter abnormity switching apparatus may automatically or manually
cut off the
operating table when the operating table breaks down or is required to be powered off in order to ensure uninterrupted power supply of field real devices, thereby enabling
real field load operation and important significance to fault hidden trouble discovery of electric meters.