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 EXTENSION, OPEN-CIRCUIT DETECTION INTERFACE MODULE IM 153-2 HF OR IM 153-4 HF POSSIBLE