JeremyAdair87
Member
So one maintenance guy in my plant advocates negative logic and supplying power to all Commons. The plant is switching to a new product line and the old modular machines are being phased out.
The maintenance man told everyone that the negative logic is tied to safety and that positive logic is not safe. He also goes into the concept of failure mode analysis about shorts and what he would rather see happen in that event. I would rather see a fused output or isolation relays on each output.
This concept mystifies me, but we are having trouble finding maintenance men that can follow negative logic.
My PLC designs and the main hardware EE are going to change the standard in the plant to sourcing outputs and sinking inputs. I just can't seem to find anything on safety and npn vs pnp. I need to make an informed decision.
Penny for your thoughts?
The maintenance man told everyone that the negative logic is tied to safety and that positive logic is not safe. He also goes into the concept of failure mode analysis about shorts and what he would rather see happen in that event. I would rather see a fused output or isolation relays on each output.
This concept mystifies me, but we are having trouble finding maintenance men that can follow negative logic.
My PLC designs and the main hardware EE are going to change the standard in the plant to sourcing outputs and sinking inputs. I just can't seem to find anything on safety and npn vs pnp. I need to make an informed decision.
Penny for your thoughts?