Digital input modules record 24 V DC or 230 V AC signals in the plant and forward them to the PLC. Switches and 2, 3 or 4-wire proximity switches can be connected.

High Feature modules feature configurable parameters and diagnostic functions and can thus be freely adapted to the respective process requirements.

Low cost input modules do not have settable parameters or diagnostic functions and are therefore very easy to integrate into the engineering. They are recommended for use in locations where only very few input channels are necessary or under conditions of use in which a high number of channels must be implemented in a very limited space.

Both module types can be used side by side in one station as required. Standardized features and shared system accessories guarantee easy handling.

The following digital input modules with a width of 35 mm are available:

• DI 16x24VDC HF;
  digital input module with 16 channels for acquiring 24 V DC signals; one potential group; input delay 0.05 … 20 ms; input type 3 (IEC 61131); parameterizable diagnostic alarms and hardware interrupts; option of using two channels for simple counter functions up to 6 kHz
• DI 32x24VDC HF;
  digital input module with 32 channels for acquiring 24 V DC signals; two potential groups; input delay 0.05 … 20 ms; input type 3 (IEC 61131); parameterizable diagnostic alarms and hardware interrupts; option of using two channels for simple counter functions up to 6 kHz
• DI 16x24VDC HS;
  digital input module with 16 channels for acquiring 24 V DC signals; two potential groups; input delay 0.05 … 20 ms; input type 2 (IEC 61131); isochronous mode up to 250 μs; parameterizable diagnostic alarms and hardware interrupts; option of using four channels for simple counter functions up to 20 kHz; pulse stretching; chatter monitoring, signal inversion
• DI 16x24VDC SRC BA;
  digital input module with 16 channels for acquiring 24 V DC signals; sourcing input; one potential group; fixed input delay 3.2 ms; input type 3 (IEC 61131)
• DI 16x230VAC BA;
  digital input module with 16 channels for acquiring 230 V AC signals; four potential groups; input delay 20 ms; input type 1 (IEC 61131)
• DI 16×24…125VUC HF;
  digital input module with 16 channels for acquiring 24 … 125 V UC signals; 16 potential groups; input delay 0.05 … 20 ms (DC) or 20 ms specified for (AC); parameterizable diagnostic alarms and hardware interrupts
• DI 64x24VDC SNK/SRC BA;
  digital input module with 64 channels for acquiring 24 V DC signals; source-sinking input; four potential groups of 16 channels each; fixed input delay 3.2 ms; input type 3 (IEC 61131); connection of the signals via SIMATIC TOP connect
• DI 16xNAMUR HF;
  digital input module with 16 channels for acquiring NAMUR signals (8.2 V DC); two potential groups; input delay 0.05 … 20 ms; parameterizable diagnostic alarms and hardware interrupts; option of using four channels for counter functions up to 20 kHz; pulse stretching; chatter monitoring; signal inverting; discharge of 8.2 V directly on the module

The following digital input modules with a width of 25 mm are available:

• DI 16x24VDC BA;
  digital input module with 16 channels for acquiring 24 V DC signals; sinking input; one potential group; fixed input delay 3.2 ms; input type 3 (IEC 61131)
• DI 32x24VDC BA;
  digital input module with 32 channels for acquiring 24 V DC signals; sinking input; one potential group; fixed input delay 3.2 ms; input type 3 (IEC 61131)

Siemens Digital Modules S7-1500 Product Specifications: