ABB AC500 PLC Hardware Manual page 1218

System Assembly, Construction and Connection
AC500-eCo > Connection and Wiring
2.5.4.5.1 Ethernet Interface
The Ethernet interface is carried out via a RJ45 jack. The pin assignment of the Ethernet inter-
face:
Interface
The supported protocols and used Ethernet ports can be found in a separate chapter.
Communication via Modbus TCP/IP is described in detail in a separate chapter.
2.5.4.5.2 Wiring
Cable Length For the maximum possible cable lengths within an Ethernet network, various factors have to be
Restrictions taken into account. Twisted pair cables (TP cables) are used as transmission medium for 10
Mbit/s Ethernet (10Base-T) as well as for 100 Mbit/s (Fast) Ethernet (100Base-TX). For a trans-
mission rate of 10 Mbit/s, cables of at least category 3 (IEA/TIA 568-A-5 Cat3) or class C
(according to European standards) are allowed. For fast Ethernet with a transmission rate of
100 Mbit/s, cables of category 5 (Cat5) or class D or higher have to be used. The maximum
length of a segment, which is the maximum distance between two network components, is
restricted to 100 m due to the electric properties of the cable.
Furthermore, the length restriction for one collision domain has to be observed. A collision
domain is the area within a network which can be affected by a possibly occurring collision (i.e.
the area the collision can propagate over). This, however, only applies if the components
operate in half-duplex mode since the CSMA/CD access method is only used in this mode. If
the components operate in full-duplex mode, no collisions can occur. Reliable operation of the
collision detection method is important, which means that it has to be able to detect possible
collisions even for the smallest possible frame size of 64 bytes (512 bits). But this is only guar-
anteed if the first bit of the frame arrives at the most distant subscriber within the collision
domain before the last bit has left the transmitting station. Furthermore, the collision must be
able to propagate to both directions at the same time. Therefore, the maximum distance
between two ends must not be longer than the distance corresponding to the half signal propa-
gation time of 512 bits. Thus, the resulting maximum possible length of the collision domain is
2000 m for a transmission rate of 10 Mbit/s and 200 m for 100 Mbit/s. In addition, the bit delay
times caused by the passed network components also have to be considered.
The following table shows the specified properties of the respective cable types per 100 m.
Table 210: Specified cable properties:
Parameter
Attenuation [dB / 100m]
NEXT [dB / 100m]
ACR [dB / 100m]
Return loss [dB / 100m]
1218
Pin
1
2
3
4
5
6
7
8
Shield
10Base-T [10 MHz]
10.7
23
N/A
18
3ADR010121, 13, en_US
Description
Tx+
Tx-
Rx+
NC
NC
Rx-
NC
NC
Cable shield
100Base-TX [100 MHz]
23.2
24
4
10
Transmit Data +
Transmit Data -
Receive Data +
Not connected
Not connected
Receive Data -
Not connected
Not connected
Functional earth
2019/04/17