Electrical Configuration Of The S5-95U With External I/Os - Siemens SIMATIC S5-90U System Manual

S5-90U/S5-95U
3.4.2

Electrical Configuration of the S5-95U with External I/Os

Figures 3-27 and 3-28 show different configuration possibilities. Pay attention to the following points
when you design your configuration.
• You must have a main switch (1) in accordance with VDE 0100 for your PLC, the sensors, and
the actuators.
• You do not need an additional fuse (2) to connect your PLC and the load circuit to power if your
radial lines are a maximum of 3 meters (9.84 feet) long and are inherently earth-fault-proof and
short-circuit-proof.
• You need a load power supply (3) for 24 V DC load circuits.
You need a back-up capacitor (rating: 200 µF per 1 A of load current) if you have non-stabilized
load power supplies.
• You should ground the load circuit at one end.
ground conductor on the load power supply (terminal M) or on the isolating transformer.
You must provide earth-fault monitoring for any non-grounded load circuits.
• You must separately fuse (5 and 6) the load voltage for sensor circuits and for actuator circuits.
• You must connect the standard mounting rail of the S5-95U to the ground conductor through a
capacitor (7), (to suppress high-frequency noise) for non-grounded configurations.
• You must have a low-resistance connection between the standard mounting rail and the
cabinet's chassis ground (9) for grounded configurations.
• You need a power fuse (8) to protect against a short-circuit occurring in the power supply.
EWA 4NEB 812 6115-02b
Installation Guidelines
Provide a removable connection (4) to the
3-27