Siemens Automation System S7-400 - Manual (Page 155)

Maintenance
7-7
Automation System S7-400 Hardware and Installation
A5E00850741-01
7.4 Replacing Digital or Analog Modules
Slot Numbering
If you have provided the modules in your system with slot numbering, you must
remove the number from the old module when replacing it and apply the number to
the new module.
Installing a Module
1. You can replace analog and digital modules in RUN mode. You must have taken
the appropriate action in your STEP 7 program to ensure correct responses
from your system.
If you are not sure whether your program will react correctly, set the CPU mode
switch to STOP.
!
Warning
Improper handling of the front connectors can result in injury and damage.
If the front connector is removed and inserted during operation, hazardous
voltages of >25 VAC or >60 VDC may be present at the pins of the module.
When such voltages are present at the front connector, modules with power
applied may only be replaced by electrical specialists or trained personnel in such
a way that the pins of the module are not touched.
2. Loosen the mounting screw of the front connector and pull it off.
3. Loosen the mounting screws of the module.
4. Swing the module out.
Note
In order that the removal and insertion of digital or analog modules can be
detected by the CPU, a minimum time of two seconds must elapse between
removal and insertion.