Schneider Electric 890USE17700 manual Improper Galvanic Isolation

The STB NIP 2212 NIM

Selecting a Source Power Supply for the Island’s Logic Power Bus

Logic Power An external 24 VDC power supply is needed as the source for logic power to the

Requirements island bus. The external power supply connects to the island’s NIM. This external supply provides the 24 V input to the built-in 5 V power supply in the NIM.

The NIM delivers the logic power signal to the primary segment only. Special STB XBE 1200 beginning-of-segment (BOS) modules, located in the first slot of each extension segment, have their own built-in power supplies, which will provide logic power to the STB I/O modules in the extension segments. Each BOS module that you install requires 24 VDC from an external power supply.

Characteristics The external power supply needs to deliver 24 VDC source power to the island. The

of the External supply that you select can have a low range limit of 19.2 VDC and a high range limit

Power Supply of 30 VDC. The external supply must be rated safety extra low voltage (SELV-rated). The SELV-rating means that SELV isolation is provided between the power supply’s inputs and outputs, the power bus, and the devices connected to the island bus.

Under normal or single-fault conditions the voltage between any two accessible parts, or between an accessible part and the protective earth (PE) terminal for Class 1 equipment, will not exceed a safe value (60 VDC max.).

CAUTION

IMPROPER GALVANIC ISOLATION

The power components are not galvanically isolated. They are intended for use only in systems designed to provide SELV isolation between the supply inputs or outputs and the load devices or system power bus. You must use SELV-rated supplies to provide 24 VDC source power to the NIM.

Failure to follow this precaution can result in injury or equipment damage.

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