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Entry type: Product note Entry ID: 4338714, Entry date: 03/11/1998

S7-400 - New Isolated Input Module

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Concerns the product with Catalog No.:                                      


6ES7 421-5EH00-0AA0    SM421, 16 DI, 120 V AC                               


A new digital input module is now available for the S7-400 PLC system.      


Salient features:                                                           


- designed for installations that require IEC type 2 inputs for 2-wire      

  proximity switches.                                                       

- can be used in applications that require separate power sources for       

  each input, e.g.:                                                         

  - motor control centers with individual control power transformers for    

    each starter or contactor.                                              

  - interfaces to a control system for skid mounted manufacturing equipment 

    or machines that have a self-contained control system and have separate 

    power feeds for each machine.                                           

  - interfaces to instrumentation equipment such as process analyzers,      

    sampling systems, combustion monitoring systems, flame safety control   

    systems etc.                                                            


Technical specifications:                                                   


Number of inputs:                         16 isolated IEC type 2            

Number of inputs per group:               1 input per common                

Rated voltages and isolation levels:                                        

Rated voltage range:                      74 ... 132 V                      

Operating frequency range:                47 ... 63 Hz                      

Number of inputs on continuously:         16 up to 60 deg. C                

Potential difference between groups:      250 V AC                          

Potential difference between inputs       1500 V AC                         

and the controller                                                          


Status indicators, interrupts, and diagnostics:                             

Status indicators                         1 green LED for each channel      

Interrupts                                None                              

Diagnostics functions                     None                              


Rated voltage input                       120 V AC                          

Voltage range for a "1" signal            74 ... 132 V AC                   

Voltage range for a "0" signal            0 ... 20 V AC                     

Input current for a "1" signal            6 ... 20 mA                       

Input current for a "0" signal            0 ... 4 mA                        

Input delay time for "0" to "1" signal    2 ms min.                         

Input delay time for "1" to "0" signal    25 ms max.                        


Type of IEC 1131 input                    Type 2                            

Connection to 2-wire BERO                 Yes                               

Connection to 2-wire proximity switches   Yes                               

Maximum quiescent current                 4 mA                              


Slots required                            1 slot                            

Weight                                    650 g                             



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