Page 2
PRELIMINARY OPERATIONS
Electrical Connections
You must connect the following cables to the RTU-A01P unit:
–
12V power cable.
–
L
ON
W
ORKS
twisted-pair cable.
–
I/O cables from the contacts/sensors.
Make sure that the 12V cable corresponds in size to the norms
indicated in the table below; the size of the 12V cable can be
calculated using the following table (maximum voltage drop on the
cable = 0.5V):
Cable length (m) = 0.5V / (I[A] load x 2 x (res [Ohm/km] /1000))
Type of cable
Length (m) in relation to base load
AWG
mm2
Ohm/Km 100 [mA] 200 [mA] 500 [mA]
1 [A]
2 [A]
5 [A]
10
5,25
3,41
733
367
147
73
37
15
12
3,3
5,7
439
219
88
44
22
9
14
2
8,8
284
142
57
28
14
6
16
1,3
14
179
89
36
18
9
4
18
0,9
21
119
60
24
12
6
2
20
0,6
34
74
37
15
7
4
1
22
0,35
52
48
24
10
5
2
1
•
The L
ON
W
ORKS
1
data cable must be twisted-pair.
•
In a free-topology configuration, the sum total of the sections must
not exceed 500m.
•
In a bus configuration, the sum total of the sections must not
exceed 2700m.
•
In a free-topology configuration, activate the 50ohm terminator by
placing the appropriate jumper on the FTT10A plug-in of the
TemaServer.
•
In a bus configuration, place two terminators (with resistance
values of 100ohm 1% ½W) at the two ends of the bus.
•
Check that the length of the L
ON
W
ORKS
1
data cable corresponds
to the norms indicated in Table 1.
1
L
ON
W
ORKS
®
is a trademark of the Echelon Corporation
