2
019-
02
28
Appendix
5.2
Data cables and accessories
RS-485 data cable
For the RS-485 data transfer path, a four-wire, shielded, twisted pair data cable must be used.
One wire pair is used for the supply voltage, and one pair for the RS-485 data connection. The
maximum length of the cable depends on the capacity of the data cable
—
core-core
—
for data
transfer, and on the cross section of the cables for power supply to the WCS readers. For data
transfer, a small core cross section and thus small cable capacitance is an advantage,
whereas for the power supply, the largest possible cross-section is required. The table below
shows the possible cable lengths depending on the cable cross section.
In the calculations, the worst-case scenario was assumed: All WCS readers are located at the
end of the data line. In the case of large cable lengths, and when connecting multiple WCS2
readers with heating, 6-wire data cables (3 x 2) can be used. These data cables use two pairs
for the power supply (doubling the cable cross-section), and one pair for the RS-485 data line.
The table shows the possible cable lengths depending on the cable capacitance (core-core).
The number of connected WCS readers is of no significance.
WCS-DCS / WCS-DCF data cables
There are 2 types of data cable available:
. WCS-DCS for stationary cable routing
. WCS-DCF for trailing cable and drag chain installations.
The data cables are twisted pairs and have a tinned copper braided shield. The braided shield
surrounds all wire pairs. The parameters of the data cable for RS-485 and SSI data transfer
applications are listed in the table below.
Capacitance core-
core
RS-485 interface
19.2 KB (LS246)
62.5 KB (LS221)
187.5 KB (LS211)
60 pF
500 m
500 m
300 m
90 pF
500 m
450 m
275 m
120 pF
500 m
400 m
250 m
WCS-DCS
WCS-DCF
Capacitance (core-core)
95 pF/m
60 pF/m
Cross section
0.14 mm
2
0.25 mm
2
Number of wires
6 (3 x 2)
6 (3 x 2)
External diameter
5.8 mm
7.5 mm
Temperature range
-30
°
C ... 70
°
C
-40
°
C ... 70
°
C
Order designation
WCS-DCS
WCS-DCF
