Siemens SM521 Digital Input Module

Manufacturer: Siemens

16 and 32-channel digital input modules

For flexible adaptation of the controller to the corresponding task

For subsequent expansion of the system with additional inputs

35 mm wide modules with parameters and diagnostic functions

25 mm wide modules for use in tight spaces:

particularly economical, without parameters or diagnostic functions

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Features Applications Model

Mounting on the S7-1500 mounting rail using one single screw
35 mm modules: Standardized 40-pin front connector using screw terminal or push-in technology (cannot be used for 25 mm modules)
25 mm modules: Standardized 40-pin front connector using push-in technology (cannot be used for 35 mm modules)
Standardized, harmonized front connector assignment for easier wiring
Connectable core cross-sections: 0.25 mm2 to 1.5 mm2 (AWG24 to 16)
Integrated potential bridges for flexible creation of potential groups (35 mm modules only)
Prewiring position of the front connector
Front flap with expandable cable compartment, even if fully wired
Unambiguous labeling on front of module: Channel numbers labeling
Cabling diagram
Included in the scope of delivery:
One labeling strip for manual labeling
One U connector
Printed front door
Front connector (for 25 mm modules only)

Digital input modules record 24 V DC or 230 V AC signals in the plant and forward them to the control. Switches and 2, 3 or 4-wire proximity switches can be connected.
35 mm wide input modules have settable parameters and diagnostic functions and can thus be adapted flexibly to the respective process requirements.
Low cost 25 mm wide 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. Uniform features and shared system accessories guarantee easy handling.

Mfr. Part No.	Description
6ES7521-1BH00-0AB0	S7-1500, DI 16X24VDC HF