Relay safety light curtain monitoring, emergency stop and safety door ume two channels with manual and automatic monitoring and 3NA 1NF, 24V input voltage / ac, category 4 / PL ISO 13849-1, as SILCL 3 IEC 62061 SIL 3 IEC 61508, model PSR-SPP-24UC / ESL4 / 3X1 / 1X2 / B. Phoenix.