Technical Description; As-Interface Operation With 24 V Voltage (As-I Power24V) - Siemens SIMATIC NET CP 343-2 Manual

Technical description

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AS-Interface operation with 24 V voltage (AS-i Power24V)

Description
The AS-Interface cable transports communication signals as well as supply voltage for the
modules and sensors / actuators (depending on module type). The nominal supply voltage is
normally 30 V DC and is supplied by an AS-Interface power supply unit. This power supply
unit also contains the data decoupling circuit required to operate the system.
Following enhancement of the AS-Interface specification in 2010, it is now possible to use a
nominal supply voltage of 24 V DC, which means that standard power supply units can be
employed. In this case, the following requirements must be fulfilled:
● An external data decoupling module is connected between the power supply unit and
● All components are approved for a 24 V DC supply voltage.
In order to limit the voltage drop on the AS-Interface cable, the maximum permissible cable
length specified for a 24 V DC supply voltage is 50 m. The extension plug cannot be used to
extend the cable length.
The AS-Interface method of communication is identical for both 30 V and 24 V supply
voltages. The possible number of addresses and slaves on the AS-Interface network is
therefore unaffected by the supply voltage used. Communication signals must be decoupled
from the power supply. The data decoupling circuit required is integrated in standard AS-
Interface power supply units (30 V DC).
CAUTION
Using a standard 24 V DC or 30 V DC power supply unit
 The AS-Interface system is designed to comply with protection class III (PELV) in
 When you use a standard 24 V DC or 30 V DC power supply unit, you must install a
Modules
● CP 343−2 (6GK7 343-2AH01-0XA0) and
● CP 343−2 P (6GK7 343-2AH11-0XA0)
with product version 02 or higher have been approved for operation with 24 V DC and
30 V DC.
CP 343-2/CP 343-2 P AS-Interface Master for SIMATIC S7
Supplement to Operating Manual, 08/2010, A5E03006584020A-01
other bus components (master and slaves).
accordance with IEC 61140. For this reason, the standard 24 V DC or 30 V DC power
supply unit must also comply with these requirements!
data decoupling module between the power supply unit and AS-Interface network!
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