
AS‑i connection for all variants of the function modules
The starter (contactor or contactor assembly) is controlled via the process image output of
the AS‑i connection in the basic module.
The status of the starter is signaled to the control via the process image input of the AS‑i
connection in the basic module.
24VDCauxiliary voltage
To control the contactor coils, the 24VDC auxiliary voltage must be applied.
To detect the switch position of the contactor contacts, to ascertain the error condition
"Contact welded", and to monitor the line voltage (L1-L2), the 24VDC auxiliary voltage must
be applied.
If the 24VDC auxiliary voltage is disconnected, the contactor coils are de-energized, even if
the AS‑i voltage is still applied.
With welded contacts, the line voltage (L1‑L2‑L3) can be applied at the main contacts of the
contactors, even if the 24VDC auxiliary voltage is disconnected.
The power supply unit for the 24VDC auxiliary voltage must comply with the ES1
(IEC62368-1) standard or PELV (Protective Extra Low Voltage) requirements.
SITOP power supplies are recommended, see Catalog
KT 10.1, https://support.industry.siemens.com/cs/ww/en/view/109745655 (https://
support.industry.siemens.com/cs/ww/en/view/109745655)
For more information, see also Section 10.2 "Connecting the function modules for AS-
Interface".
A safety-oriented shutdown can be achieved by switching o the 24VDC auxiliary voltage.
Feedback circuit monitoring, which is required to achieve the diagnostic coverage, must
be implemented with mirror contacts on the contactor. The diagnostic information that
the function module makes available via AS‑Interface is only generated when the 24VDC
auxiliary voltage is applied, and can therefore not be used for the feedback circuit monitoring
of the safety function.
See also Contactors in safety applications – Guide of use
https://support.industry.siemens.com/cs/ww/en/view/109807687 (https://
support.industry.siemens.com/cs/ww/en/view/109745655)
AS-i addressing unit
The AS‑i addressing unit (3RK1904‑2AB02) is used to assign an address to the AS‑i connection
in the basic module during commissioning. To do this, plug the addressing cable of the
addressing unit in the addressing socket on the basic module. For the contactor function test,
the AS‑i addressing unit enables the starter to be controlled and the status of the starter to be
read in without the use of an AS‑i master or a control (PLC).
The AS‑i address can also be assigned via the AS-i master, e.g. via the corresponding online
function in the TIA Portal.
The advantage of using the AS-i addressing device is that it is easy to assign the address to
the correct starter by plugging the addressing cable into the basic module of the associated
starter.
Product description
4.1Properties
SIRIUS 3RA2712 function modules for AS-Interface
20 Equipment Manual, 11/2022, A8E96801707001A/RS-AD/006