Nowadays, most machines/equipment come equipped with a digital HMI screen(s) rather than the old-fashioned “Start/Stop” buttons. Most see this as an improvement in using technology. However, for those with “machine specific” LOTO procedures, these HMI screens pose a challenge regarding “verifying ZES” for the electrical energy sources.
In the old days, we returned to the control panel and pushed the “green” Start button as shown below. A straightforward means to verify electrical is at a ZES.
Today, with the newer HMI digital screens, once the electrical is locked out, the screen goes “dark.” So, there is no longer a “Start” button to push.
Yet in our travels, we see the vast majority of “machine specific” procedures using the old wording telling the authorized employee to use the “start” button to verify electrical is at a ZES.
However, once the electrical is locked out, the authorized employees will see this when they return to the HMI screen.