Protective Devices And Insulation Monitoring Devices - Siemens S5-100U User Manual

S5-100U
3.5

Protective Devices and Insulation Monitoring Devices

When you configure systems that have programmable controllers, follow the relevant VDE
regulations (e.g., VDE 0100, VDE 0113 or VDE 0160). Pay special attention to the following points:
• Prevent conditions that can endanger people or property.
• When power is restored after a power failure or after EMERGENCY OFF devices are
deactivated, machines must not be able to restart automatically.
• When a programmable controller malfunctions, commands for EMERGENCY OFF devices and
safety limit switches must remain effective under all circumstances. These safety measures
must directly affect the actuators in the power supply.
• When EMERGENCY OFF devices are activated, safety must be guaranteed for both people and
the system as follows:
- Actuators and drives that could cause dangerous situations (e.g., main spindle drives for
machine tools) must be shut off.
- Actuators and drives that could endanger persons or the controlled system by being shut off
(e.g., clamping devices) must not be shut off by EMERGENCY OFF devices.
• The programmable controller must be able to record the activation of EMERGENCY OFF
equipment, and the control system must be able to evaluate it.
Protection in Case of Indirect Contact
Accessible parts must not be dangerous to touch even if there is a fault.
This requirement is fulfilled if you make all accessible metal parts electrically safe that could be
dangerous to touch in the event of a failure (e. g, standard mounting rails, transoms, the cabinet).
This is done by connecting these parts to the protective ground conductor (PE). The maximum
permissible resistance between the protective-conductor terminal and the accessible part that
requires protecting is 0.5 .
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Installation Guidelines
EWA 4NEB 812 6120-02