1-8
Series 90-30 PLC Installation and Hardware Manual
–
August 2002
GFK-0356Q
1
The next figure shows a system that has a CPU baseplate, one Expansion rack and three Remote
racks. Notice that the last rack, the one at the end of the I/O Expansion Bus, must be terminated.
A convenient way of terminating the bus is with an IC693ACC307 I/O Bus Terminator Plug, as
shown.
C
P
U
CPU BASEPLATE
EXPANSION BASEPLATE
REMOTE BASEPLATE
REMOTE BASEPLATE
EXPANSION
BASEPLATE
MAXIMUM DISTANCE
FROM CPU = 50 FEET
(15 METERS)
CPU
BASEPLATE
REMOTE
BASEPLATE
I/O BUS
TERMINATOR
PLUG
IC693ACC307
REMOTE BASEPLATE
REMOTE
BASEPLATE
MAXIMUM DISTANCE
FROM CPU = 700 FEET
(213 METERS)
REMOTE
BASEPLATE
Figure 1-9. Connecting Expansion and Remote Baseplates
What is the Difference Between Expansion and Remote baseplates?
The main factor to consider is distance. How far will the baseplate be from the CPU baseplate? If
the cabling distance from the CPU baseplate is 50 feet (15 meters) or less, use an Expansion
baseplate. The Expansion baseplate is preferable because of its higher communication speed with
the CPU baseplate. However, if a baseplate must be located where it requires a cabling distance
from the CPU rack in excess of 50 feet, an Expansion baseplate will not work - a Remote baseplate
must be used. The limit for a Remote baseplate is a cabling distance of 700 feet (213 meters) from
the CPU baseplate to the farthest Remote baseplate.