The modules are designed in accordance with EN50 178 with reinforced isolation. The safety circuit is controlled with one or two channels, with cross circuit detection for safety category 4. The PSR modules meet the requirements of EN 954-1 Category 4 and can be used for the Stop Category 0 or 1 in accordance with EN 60204. They are well-suited for Emergency Stop applications, guard-door monitoring and two-hand operation.