Siemens SIMATIC ET 200SP System Manual page 76

To remove a BaseUnit, follow these steps:
1. Switch off all supply voltages on the ET 200SP distributed I/O system.
2. Loosen the wiring on the BaseUnit (with a 3 to 3.5 mm screwdriver).
3. Removing (from the right):
Press the mounting rail release on the relevant BaseUnit. Move the BaseUnit parallel to
the right and swivel the BaseUnit off of the mounting rail while pressing the mounting rail
release.
Removing (from the left):
Press the mounting rail release on the relevant BaseUnit and the BaseUnit located to its
right. Move the BaseUnit parallel to the left and swivel the BaseUnit off of the mounting
rail while pressing the mounting rail release.
Note: The mounting rail release is located above the BaseUnit
Figure 5-5
Distributed I/O system
System Manual, 09/2019, A5E03576849-AJ
Removing the BaseUnit (removing from the right)
5.5 Mounting BaseUnits for I/O modules
Installation
75