SIMATIC S7/PCS7, digital input SM 321, 16 DI; 24 V DC, 1 x 40-pole, diagnostics-capable, for contacts (wired/ not wired), NAMUR encoder, 3/4-wire BERO, with chatter monitoring; pulse stretching, open-circuit detection connection IM 153-2 HF or IM 153-4 HF possible