i did use wincc (HMI) create a button and name it as tagout .this button provide with password where only maintenance personal and manager level carried it..once they press the button it shut down the wanted out ( create ladder as N/C) and i fix relay to indicate which panel (stater Been tagout) .after that maintenace personal will do lockout at Panel stater panel and a signal back to PLC as input and massage appear on HMI mention been lockout by maintenance personal.
even when operator accidently click it it wont start the stater board or energize the output.
No way an HMI would work as LOTO in the states. It MUST be a mechanical disconnection of power supply voltage, meaning if you are locking out a motor it must disconnect the power portion of the motor circuit.