Safety
Safety Isolation Systems
ElectroGuard™ Operation
The ElectroGuard system is placed between the energy source and the machine. The Control Module controls and verifies the ElectroGuard system function. Every function is commanded and monitored for proper completion, being comprised of the ladder logic of electro-mechanical devices & safety relays. The control module sends and receives signals from the Electrical Isolation Module, the Pneumatic Isolation Module and the Remote Lockout Stations. At any time, if the ElectroGuard Power Panel ground is broken, or a fault occurs within the isolation system, the ElectroGuard system will shutdown. Under a fault or shutdown condition of the ElectroGuard system, the "system Isolated" light will not be illuminated. No light means no entry.
The ElectroGuard system is powered by a 120V control transformer in the power panel and 24V DC power supply within the control module. All external modules are powered from the power panel; the RLS is a 24V DC low voltage signal, and the Pneumatic Isolation Module is 120V AC.
Sequence of Isolation Operation
- The Remote Lockout Station initiates the isolation sequence, by an operator turning the handle from the ON to OFF position.
- The control module responds by commanding both isolation modules, electrical and pneumatic, to isolate and verify isolation.
- The electrical isolation module opens the series contactors, the voltage sense circuit monitors the isolated voltage, when safe the grounding contactor connects the isolated electrical lines to the isolated ground. Electrical Isolation is now completed and verified by the control module.
- The pneumatic isolation module opens the pneumatic value with its own control module, and redundant pressure sensors verify isolation has completed. Pneumatic Isolation is now completed and verified by the pneumatic control module.
- After successful isolation, the control module illuminates that operator’s Remote Lockout Station “system isolated” light.
- An operator then applies a LOTO lock to the Remote Lockout Station handle, and it is safe to work on the machine.
This entire sequence is less than 10 seconds.