DCM 1271 data decoupling module for SIMATIC S7-1200
With the aid of the DCM 1271 data decoupling module, the AS-Interface network can also be supplied with 24 V DC or 30 V DC from a standard power supply unit and the transmission of data and power can be implemented on one cable.
The data decoupling unit DCM 1271 has the same type of enclosure as an S7‑1200 module and can therefore be perfectly combined with the AS‑i master CM 1243‑2.
The data decoupling unit DCM 1271 has no connection to the backplane bus of the SIMATIC S7‑1200 and is therefore not counted as a communication module for the calculation of the maximum configuration.
The integrated ground fault detection functions with grounded and non-grounded power supply: The connection of negative pole and ground (upstream from the data decoupling module) customary with 24 V DC power supplies is permitted. A ground fault to the negative or positive pole on the AS-Interface network (behind the data decoupling module) is identified and signaled via LED and a transistor output.
The AS-Interface data decoupling module is designed for AS-Interface networks with 30 V or 24 V supply (AS-Interface Power24V).
Operation of an AS-i network with the data decoupling module and a 30 V standard power supply unit is technically equivalent to the use of an AS-Interface power supply unit and offers the service-proven features of AS-Interface for all applications.
AS-Interface Power24V uses a 24 V power supply unit in conjunction with a data decoupling module and is particularly suitable for
The power supply units must comply with the PELV (Protective Extra Low Voltage) or SELV (Safety Extra Low Voltage) standards, have a residual ripple of < 250 mVpp, and in the event of a fault must limit the output voltage to a maximum of 40 V. We recommend:
Note on AS‑i Power24V:
The length of an AS-i Power24V network is restricted to 50 m in order to limit the voltage drop along the cable.
AS-i masters, AS-i slaves and the sensors and actuators supplied through the AS-i cable must be designed for the reduced voltage. Sensors and actuators for the standard voltage range of 10 to 30 V can be supplied with sufficient voltage.
Please also continue to observe the requirements specified in the section "Extension of AS-i Power24V" for implementation of AS-i Power24V, see "AS-Interface → Introduction → AS-Interface Specification → Extension of AS-i Power24V".
Configuration of an AS‑i Power24V network with AS‑Interface data decoupling unit DCM 1271
Additional information on AS‑i Power24V see "AS-Interface System Manual", .
Manuals see .