redundancy follows the same principles as the communication interface redundancy
in the Advant Controller 400 Series.

Communication Interface Redundancy in AC 800M
The communication interface redundancy in AC 800M is achieved by using two
CI869 modules that are connected to the same AC 800M controller. One of the
CI869 modules is configured as primary, while the other is configured as backup.
Failover time for CI869 and Double DSP timeout
The failover time is the time that the backup CI869 takes to function as primary
without error, if the primary CI869 does not work properly.
The other stations on the AF 100 bus do not influence the failover of the CI869
modules.
The backup CI869 is supervising that the primary CI869 is sending its CDPs with
the expected cycle time. If the backup CI869 detects that the Primary CI869 does
not send its CDPs as it should, it triggers the AC 800M controller to perform a
failover of CI869.
The ‘Double DSP timeout’ parameter must be enabled for an AF 100 station that is
receiving DSP data from another AF 100 station that uses redundant communication
interfaces. For details, refer to the Online Help of Control Builder.
Cable Redundancy and Partner Supervision
In a redundant configuration, the primary and the backup CI869 modules supervise
that the communication happens between them.
The backup CI869 supervises that the primary CI869 sends its CDPs as it should.
For this, it is required that both the cables that are connected to the backup CI869
have bus traffic.
If any of the cables connected to the backup CI869 are without bus traffic for 10 ms
or more, the Partner Supervision is disabled, and:
• If the parameter "Cable" on the CI869 hardware editor is set to Redundant, the
Partner Supervision not active unit status bit is set on the backup
CI869 hardware unit.
• If the parameter “Cable” is not set to Redundant, the status bit is not set.
However, a warning stating that the Partner Supervision requires redundant
lines is displayed during the download of this redundant CI869 configuration to
the controller.
Advant Fieldbus 100 Length Concept
The Advant Fieldbus 100 length concept helps to configure the bus for three
different lengths and thereby achieve different combinations of physical distance
and performance.
The possible lengths for AF 100 bus are:
• 2000 meters (6500 ft., maximum physical distance is 1700 meters).
• 8500 meters (27600 ft., maximum physical distance is 7600 meters). The
throughput must be 40% of the throughput on 2000 meters.
• 15000 meter (48750 ft., maximum physical distance is 13300 meters). The
throughput must be 15% of the throughput on 2000 meter.
The Advant Fieldbus 100 bus length is set while defining the communication
interface.
See Section 2, Advant Fieldbus 100 Concepts, for detailed rules of how to calculate
bus length in an Advant Fieldbus 100 network. See Section 3, Configuration of
Advant Fieldbus 100 for calculation of performance and bus load.
Figure 5 shows an example of an Advant Fieldbus 100 network with length of
15000 meters

Figure 5. An example of using the Advant Fieldbus 100 length concept for 15000
meter.
In Figure 5, the necessary terminations and groundings are not shown completely.
Table 4 describes the communication interfaces that support the bus lengths of
8500m (27630 ft.) and 15000m (48750 ft.).

Physical Overview
General
A station is connected to the AF 100 bus through a communication interface and a
particular modem. Table 5 describes the communication interfaces and modems that
are used for the different station types and media.
Table 5. Communication Interfaces and modems for different station types and media

The allowed station numbers for Advant Controller 400 Series and
AC 100 OPC Server are 1 to 80. For other controllers and AF 100 Stations, station
numbers 1 to 79 are allowed.
Communication Interfaces
There are several communication components that can communicate on the
Advant Fieldbus 100. The communication interfaces that have the capability to be
Bus Administrators are CI520, CI522, CI525, CI526, CI527, CI626, CI627, CI630,
and CI631.
Advant Controller 70
The Advant Controller 70 has integrated Twisted Pair Modems for connection to
Advant Fieldbus 100.
Advant Controller 110
The Advant Controller 110 is connected to the Advant Fieldbus 100 via a CI626
communication interface for coaxial media or a CI627 communication interface for
twisted pair media.
Advant Controller 160
The Advant Controller 160 is connected to the Advant Fieldbus 100 via a CI626 or
CI630 communication interface for coaxial media or a CI627 or
CI631communication interface for twisted pair media.
Advant Controller 400 Series
The Advant Controller 400 Series is connected to the Advant Fieldbus 100 via
single CI520 or via single or redundant CI522 communication interface, and
modem TC625 for coaxial media or modem TC512/TC516 for twisted pair media.