I'm using this Phoenix Contact DIN rail relay, DigiKey part 277-17665-ND (data sheet). I thought it would be prudent to add a flyback diode, but looking at the data sheet, it vaguely suggests it already has protection.
In the section “Input Data”, there’s a line “Type of protection” with value “Free-wheeling diode.” In the section “Output Data,” “Type of protection” says “Reverse polarity protection” and “Surge protection.” Later it says the rated surge voltage is 4 kV.
I don’t know much about industrial controls, but it would be convenient if they could handle inductive kickback without external protection, so I wonder if they don’t.
Will my relay be okay without additional protection?