The power supply unit must be safety-separated in accordance with
DIN EN 50 178, section 5.2.18.1. Transformers must be designed with safety
separation in accordance with DIN EN 60 742.
If these requirements are complied with, the 24 V supply voltage is rated as
safety-separated extra-low voltage in accordance with DIN EN 50 178, section
5.2.8.1. This voltage is designed either as safety extra-low voltage (SELV)
without ground connection of the reference conductor or as protective extra-
low voltage (PELV) with ground connection of the reference conductor.
A three-phase power supply unit with easy full-bridge rectification is appropri‐
ate. The ripple voltage content must not exceed 5 %.
All 24 V voltage supply lines have to
●
be laid such that they are isolated from lines carrying higher voltages, or
●
be insulated to a particularly high degree, with the insulation having to be
designed for the highest voltage present (see EN 60 204-1: 1997, section
14.1.3).
Any peripherals, such as digital sensors/actuators, which are connected to the
interfaces of the IndraControl L10, have to comply also with the criteria of safe‐
ty-separated circuits.
8.2.3
24 V Power Supply
Setup without Electrical Isolation
The most easiest connection method is the establishment of an electrical iso‐
lation between the internal logic and the peripheral supply.
In this case, a power supply unit is appropriate to supply the
IndraControl L10. It is not permitted to use an autotransformer to ensure com‐
pliance with overvoltage category II.
Fig.8-2:
Setup without electrical isolation
Setup with Electrical Isolation
According to DIN EN 60 204-1, electrical isolation should be provided between
the logic of the central processing unit and the I/O interfaces of the peripheral
Project Planning Manual | Rexroth IndraControl L10
Electric Drives
and Controls
| Bosch Rexroth AG
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