Siemens SIRIUS 3RT2 Manual page 46

Mounting
7.3 Mounting
Mounting the function module for star-delta (wye-delta) start
①
②
③
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Check that the interlock slide is engaged in the uppermost position.
Release the cover cap on the interface connection.
Remove the cover cap for the interface connection from the connector by lifting it up and out.
SIRIUS 3RA28 function modules for mounting on 3RT2 contactors
Manual, 02/2019, A5E03656507620A/RS-AD/005