Operational unit symbols refer to the comparison between two values of a characteristic quantity, such as voltage, current, frequency, temperature, pressure ...
|Higher than ...||Lower than ...|
|Higher or lower than ...||Equals ...|
|Equal to zero||Close to zero|
|Overcurrent release||Defetuosa actuated relay voltage|
|Relay low power||Relay blocked rotor|
|Relay maximum and minimum current||Excess counter|