36
NRG 26-61 - Installation & Operating Manual -
819874-00
Connecting the CAN bus system
Bus line, cable length and cross-section
■
■
Use a shielded, multi-core, twisted-pair control cable, e.g. UNITRONIC
®
BUS CAN 2 x 2 x .. mm
2
or RE-
2YCYV-fl 2 x 2 x .. mm
2
as the bus line.
■
■
Pre-wired control cables (with plug and coupling) are available as accessories in various lengths.
■
■
The baud rate (transfer rate) is determined by the cable length between the bus terminal devices, and
the wire cross-section is determined by the overall power input of the measuring sensors.
■
■
0.2 A at 24 V is required per sensor. With five sensors, there is therefore a voltage drop of approx. 8 V
per 100 m when using cables of 0.5 mm². In this case, the system is operating at its limits.
■
■
With five or more sensors and a cable length of ≥ 100 m, the wire cross-section needs to be doubled
to 1.0 mm².
■
■
At larger distances of > 100 m, the 24 V DC supply can also be connected on site.
Example
5
Shield
3
3
5
5
120
Ω
CH
CL
120 Ω
CH
CL
S
+ 24 V
- 0 V
CH
CL
S
CL
-
CH
+ 24 V
S
+ 24 V
- 0 V
CH
CL
S
+ 24 V
- 0 V
CH
CL
S
+ 24 V
- 0 V
CH
CL
S
CH
CH
CH
CH
CL
CL
CL
CL
S
S
S
S
+
+
+
–
–
–
–
+
24V DC
24 V DC
100 - 240 V AC
120 Ω
2
7
+ 24 V
CL
CH
-
0 V
+
+
-
–
C
H
C
L
Option
URB
URS, NRR, LRR,
URW
NRG, LRG, TRV
NRG, LRG,TRV
CH = CAN High
CL = CAN Low
S = shield
Terminating
resistor
Fig. 17
