GE GFK0579B Scanner User Manual


 
2
39Chapter 2 Installation
Programmer Connections in a Multidrop Network
In a multidrop network, a programmer connected to the CPU can communicate with
the Remote I/O Scanner over the serial link, as shown below. A programmer can also
be connected directly at the remote drop. However, when the Remote I/O Scanner is
part of a multidrop network, its serial port, which is used for connection of the serial
link, is not available for direct connection of a programmer.
P
S
U
C
P
P
S
A
S
C
N
N
E
R
a44886PLC REMOTE DROP
B
C
PROGRAMMER
CONNECTION
(SERIAL)
ON
MULTIDROP
NETWORK
GENIUS BUS
SERIAL NETWORK CABLE
The illustrations that follow suggest how extra connectors may be installed to allow the
use of a programmer at various points in the system, without disturbing the serial link
between the PLC and the remote drop. When extra connectors are used, it is
important to be sure that the connections will be secure. For example, the connectors
can be permanently mounted on panels.
The illustrations show connections for a Workmaster II programmer, although a
different type of programmer could be used.
If the programmer does not have a Workstation Interface card, RS232–to–RS422
conversion must be provided at each location. A conversion box can be installed at
each drop, or one conversion box can be moved from location to location with the
programmer.
In locations where isolation is not a problem, the non–isolated RS232–to–RS422
Conversion Box (IC690ACC900) can be used.
In locations where ground potential differences may occur, it is important to provide
adequate ground isolation. Repeater/Converter Box (IC655CMM590) that provides
both RS232–to–RS422 conversion and isolation should be used.