ICP DAS USA 7000 Uses the same DC, Power Ground with Host PC/PLC for, If there is high voltage

	WARNING!! ERROR CONDITION 2: if the						7520 uses the same DC
	power	ground with			Host	PC/PLC (for	example,	Host PC/PLC
	provide non-isolated DC power source to 7520). In this situation,
(1)		The	Host PC/PLC is common ground with power ground of							7520
(2)		The power ground of				7520 is common ground with			RS-485
	Therefore the			Host PC/PLC is common ground with					RS-485 network.
That is to say, there is no isolation between Host PC/PLC and										RS-485
network. So			the	Host PC/PLC may be			damaged	if there is high voltage
transient on			RS-485 network.
	OK CONDITION: If the DC power ground of						7520 or	7520R is not common
	to any module, the				Host PC/PLC will be isolated from				RS-485 network in
	all conditions.

The power adapter PWR-24 is designed for single 7000 series modules only. The 24V DC output of the PWR-24 is isolated from its AC input. If the 7520 or 7520R is connected to the PWR-24, this PWR-24 cannot connect to the other module. Normally the Host PC/PLC uses a switching power and the DC output of this power supply is also isolated from its AC input. Therefore the DC power ground of 7520 or 7520R is isolated from Host PC/PLC. Therefore, the Host PC/PLC is isolated from RS-485 network in all condition.

PWR-24

￿7520

￿RS-232 ￿7520R ￿RS-485

￿Host PC/PLC	Connecting 256
	modules without
	repeater, 7510
	￿7000 series	￿7000 series

￿Host PC/PLC is isolated from ￿RS-485 network for ￿7520 or ￿7520R in all condition

7000 Bus Converter User Manual (version 1.2,Feb/2003, 7PH-006-10) --------------- 25