Schneider Electric 890USE19600 Version 1.0 manual Logic Power, Improper Galvanic Isolation

The STB NIB 1010 Basic NIM Module

Logic Power

Introduction	Logic power is a 5 VDC power signal on the island bus that the I/O modules require
	for internal processing. The NIM has a built-in power supply that provides logic
	power. The NIM sends the 5 V logic power signal across the island bus to support
	the modules in the basic segment.
External Source
	Input from an external 24 VDC power supply is needed as the source power for the
Power	NIM’s built-in power supply. The NIM’s built-in power supply converts the incoming
	24 V to 5 V of logic power. The external supply must be rated safety extra low
	voltage (SELV-rated).
		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
		island.
		Failure to follow this precaution can result in injury or equipment
		damage.
Logic Power
	The figure below shows how the NIM’s integrated power supply generates logic
Flow	power and sends it across the basic segment:

5V

24 V

24 VDC

26 890USE19600 April 2004