Siemens Simantic ET200SP System Manual page 237

NOTICE
Risk of hazardous system states
If you remove and insert digital output modules with the load switched on or technology
modules with the supply voltage switched on, this can result in hazardous system states.
The ET 200SP distributed I/O system or the connected sensors may be damaged as a
result.
Therefore, a digital output module may only be inserted and removed when the load is
switched off and a technology module may only be inserted and removed when the supply
voltage is switched off.
NOTICE
Risk of hazardous system states
If you remove and insert the AI Energy Meter ST with the primary-side voltage switched on
at the current transformer, this can result in hazardous system states.
The ET 200SP distributed I/O system may be damaged as a result.
• For this reason, remove and insert the AI Energy Meter ST only when the measuring
• Only when a special current transformer terminal is used which short-circuits the
Risk of injury from automatic restart
Inserting a motor starter may result in dangerous plant conditions. The motor starter can
restart again autonomously if an ON command is active.
This can result in serious injury caused by connected devices that are automatically started
up.
Withdraw and insert a motor starter only after disconnecting the load.
Distributed I/O system
System Manual, 12/2016, A5E03576849-AG
voltage on the primary side is switched off
or
secondary end of the transformer when a module is removed. Do not remove or insert
the AI Energy Meter ST until you have removed this current transformer terminal. With
the special terminal, the process can continue because the current transformer is
isolated safely. However, the measuring voltage on the module at the connections UL1-
UL3 still needs to be isolated.
WARNING
12.1 Removing and inserting I/O modules/motor starters
Maintenance
237