Vigilant
MX1-Au
Operator Manual
Document: LT0439
Page
23 October 2018
Issue 1.73
11-26
The I-HUBs are typically connected in a ring configuration as shown in
Figure 11-23.
SHLD
RXA+
RXA
-
TXA+
TXA-
RS485 PORT 1
SHLD
TXB-
TXB+
RXB-
RXB+
RS485 PORT 2
LK 11
LK 13
LK12
LK14
S
H
L
D
R
X
A
+
R
X
A
-
T
X
A
+
T
X
A
-
R
S
4
8
5
P
O
R
T
1
S
H
L
D
T
X
B
-
T
X
B
+
R
X
B
-
R
X
B
+
R
S
4
8
5
P
O
R
T
2
L
K
1
1
L
K
1
3
L
K
1
2
L
K
1
4
S
H
L
D
R
X
A
+
R
X
A
-
T
X
A
+
T
X
A
-
R
S
4
8
5
P
O
R
T
1
S
H
L
D
T
X
B
-
T
X
B
+
R
X
B
-
R
X
B
+
R
S
4
8
5
P
O
R
T
2
L
K
1
1
L
K
1
3
L
K
1
2
L
K
1
4
TXB-
TXB+
RXA-
RXA+
RXA+
RXA-
TXB+
TXB-
TX
B
-
TX
B
+
R
X
A
-
R
X
A
+
Figure 11-23
– I-HUB Ring Wiring
Links LK11, LK12, LK13 and LK14 must be installed on each I-HUB.
Wire the RS485 ring, preferably using shielded cable, from Port 2 TXB+
and TXB- to Port 1 RXA+ and RXA- on the next I-HUB, repeating around
the ring. The cable shields should be wired to the shield terminals. The
two shield screw terminals are joined together and are isolated from the
chassis and I-HUB power grounds.
In ring mode, the I-HUB network ports 1 and 2 are pre-configured to
operate at 57,600 baud. The recommended maximum cable length is
300 meters un-terminated (when using 0.75mm² screened cable). When
ports 1 and 2 are terminated, the cable length (0.75mm² screened cable)
may be increased to 1,500 meters. Termination is detailed in Section 3.9
of the I-HUB User Manual (LT0229).
Ports 1 and 2 can be combined to operate in a 2-wire ring arrangement
with other I-HUBs using fibre optic modems and fibre optic cable. Fibre
optic modems convert the RS485 signal interface into optical signals for
transfer via optical cable. Fibre optic transmission is not affected by
electrically ‘noisy’ environments and offers significant advantage where
long ‘cable’ lengths are required.
For fibre segments, I-HUB links LK11 and LK13 (Port 1), LK12 and LK14
(Port 2), (located either side of the screw terminal block) must be
removed.
Figure 11-24 shows a wiring diagram for use with OSD139AF optical
modems. These are the recommended fibre optic modems for use with
the I-HUB. These units support a maximum baud rate of 57,600 over two
fibres per leg. The DTE/DCE switch needs to be set in the DTE position.
I-HUB Copper
Ring
I-HUB Fibre
Optic Ring
