ICP DAS USA 7000 user manual Therefore the Host PC/PLC is common ground with, Network

￿7520

￿RS-232

￿RS-485

￿Host PC/PLC

￿7000 situation

Note: the power ground of ￿7000 and ￿RS-485 is

common ground.

This is the same for Adam 4000, Nudam 6000 and DATAFORTH 9B series modules.

In most applications, the 7520 are used to convert the RS-232 signal to RS-485 network. Normally the 7520 does not use the same DC power

ground as the	Host PC/PLC, and the isolation site is in the RS-232 section.
Therefore the	Host PC/PLC is isolated from RS-485 network. That is to say,

if there is any high voltage transient on RS-485 network, the Host PC/PLC will be free from damage.

WARNING!! ERROR CONDITION 1: if the 7520 are replaced by 7520R and the 7520R uses the same DC power ground with 7000. In this situation,

(1)	The	Host PC/PLC is common ground with RS-232
(2)	The	RS-232 is common ground with power ground of 7520R
(3)	The power ground of		7520R is common ground with power ground of
	7000
(4)	The power ground of		7000 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. The		Host PC/PLC may be damaged if there is high voltage transient
on RS-485 network.

7000 Bus Converter User Manual (version 1.2,Feb/2003, 7PH-006-10) --------------- 24