User Manual

7000 Bus Converter User’s Manual (Version 1.8 Jan/2006, 7PH-006-18) --------------- 21
In most applications, the p7520 are used to convert the oRS-232 signal to
rRS-485 network. Normally the p7520 does not use the same DC power
ground as the nHost PC/PLC, and the isolation site is in the RS-232 section.
Therefore the nHost PC/PLC is isolated from rRS-485 network. That is to say,
if there is any high voltage transient on rRS-485 network, the nHost PC/PLC
will be free from damage.
WARNING!! ERROR CONDITION 1: if the p7520 are replaced by p7520R and
the p7520R uses the same DC power ground with q7000. In this situation,
(1) The nHost PC/PLC is common ground with oRS-232
(2) The oRS-232 is common ground with power ground of p7520R
(3) The power ground of p7520R is common ground with power ground of
q7000
(4) The power ground of q7000 is common ground with rRS-485
Note: the power ground of q7000
and rRS-485 is
common
ground.
This is the same for
A
dam 4000, Nudam 6000 and
DATAFORTH 9B series modules.
Therefore the nHost PC/PLC is common ground with rRS-485 network.
That is to say, there is no isolation between nHost PC/PLC and rRS-485
network. The nHost PC/PLC may be damaged if there is high voltage transient
on rRS-485 network.