Контекст:
This example denotes a control situation where the alarm is automatically reset once the %kW value drops below the Hysteresis band. For protection applications, Hysteresis is typically not used and the alarm would be physically reset
A continuation is shown where the motor load drops such that it falls below the L2 Min Limit which triggers a Relay 2 alarm once %kW has remained below L2 for the duration of the delay timer Tr2
Again, the HPL420 is reset using the automatic Hysteresis function but this can also be done physically. Note also that the relay logic for the HPL420 can be programmed which is shown in the diagram as N. Inv. or Inv

Relay 1 Closed N. Inv.
Relay 1 Closed Inv.
Relay 2 Closed N. Inv.
Relay 2 Closed Inv.

http://www.wentec.com/unipower/products/pdf/hpl420instruction.pdf

там даже табличка ест, где это Inv расшифровано
стр.15
Relay 1 Relay 1 Polarity N. Inv./Invert. N.Inv. <->Inv. N.Inv. <->Inv. “Pol” N. Inverted
Relay 2 Relay 2 Polarity N. Inv./Invert. N.Inv. <->Inv. N.Inv. <->Inv. “Pol” N. Inverted