2
Basic Repeater Operation
(Refer to Figures 2A and 2B)
The REP-1 has two independent 2-wire
RS-485 repeaters that permit the addition
of another 80 ohms of wire to a Style 4
circuit by using the REP-1 at the end of the
network. When an REP-1 Repeater is in
place, there can be up to 64 nodes on that
network; however, two of the nodes are
used for the repeater module itself.
An REP-1 module uses one node on each
network pair to which it is connected. Al-
though this decreases the 32 available
nodes on a network run, the REP-1 module
adds 31 new nodes on the repeated net-
work.
The REP-1 module occupies one node on
the original network and one node on the
repeated network in both Style 4 and Style
7 wiring.
Adding a T-Tap to a System
(See Figures 2C and 2D)
I
f an REP-1 module is connected along a
Style 4 or a Style 7 network, the repeated
network can run in a new direction. This
type of setup makes it possible to have a
star configuration on the network.
Converting Style 7 to Style 4 in
a System
(See Figure 2E)
A Style 4 tap can be added to a Style 7
network by using an REP-1 module. This
is helpful when installing RCC-1s and
MOI-1s/7s in a Style 7 system if Style 7 is
not required for those modules.
When an REP-1 is used to add Style 4 to a
Style 7 network, REP-1 connects to two
nodes, thus adding 30 new nodes.
CSG-M Control of System Size
Even though the REP-1 supplies an
increased node count in a system, the total
system size is still controlled by the CSG-M.
This limit guarantees that the MXL System
can support the number of modules installed.
PROGRAMMING
(See Figure 1)
There is one switch (S1) and one jumper
(JP1) on the REP-1 that must be set before
installing the REP-1 in the MOM-4 module.
Setting the Switch on REP-1
The S1 switch on the REP-1 has two
positions available.
•
The
left-side position
(7 to 4)
of the
switch enables conversion from
Style 7 to Style 4.
•
Select the
right-side position
(NORM)
of the switch if the REP-1
is used as a repeater.
Selecting the Correct Position
for the JP1 Jumper
The REP-1 provides electrical isolation
between the local power supply and the
RS-485 lines. The JP1 jumper on the
REP-1 has two positions relating to this
feature—
PSR
and
MMB.
•
Select the
left-side position
(PSR)
for
the jumper if the REP-1 is installed in
an enclosure with a PSR-1. This set-
ting protects ground fault isolation for
the system. (See
CAUTION
on the next
page.)
•
Select the
right-side position
(MMB)
for the jumper if the REP-1 is installed
in an enclosure with an MMB so as
to protect ground fault isolation circuits
.
For additional information on the MXL/MXLV
System, refer to the
MXL/MXLV Manual,
P/N 315-092036.
