Profibus DP Mk2 Option Card Installation Manual
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Publication PUB088-005-00_1017
6.5 Single Highway Dual Channel
– FR Mode
On either the Simple or RedCom dual channel card the mode for communications may be set to FR
(Flying Redundancy) in some cases. This will require the card’s GSD file to be changed or the
parameter value altered by a PDM or FDT utility.
Redundancy
SR is the default mode; it must be altered for FR mode.
In FR mode there is one highway and a single PLC can be used. The two channels on the card each
have an address offset by 64. One channel is in Primary mode and uses the base address whilst the
other is in Backup mode using the base address plus 64. As with SR mode, the card is waiting for a
communication message on the channel that is in Primary mode and the two channels will switch their
mode whilst searching for comms. There is no discrimination between Channel 1 and Channel 2 to
determine which is in Primary mode. The two channels will both try to adopt Primary mode. The
difference here is that the PLC can communicate with the backup using a different address.
When using either type of dual channel card in FR mode the following must be set up:
Address
The two channels have address offset by 64. Setting the base
address will set the offset address. With IQ and IQT actuators the
address can be set using the IrDA communication link directly with the
actuator and the IQ setting tool. For all actuator variants the address
can be set over the highway using a Class 2 master.
Baud Rate
This is selected by the PLC, both channels adopt the same baud rate.
Slave Configuration
One of the 10 configurations for the slave must be chosen. Both
channels will use the same configuration setting.
Configuration can only be carried out on the Primary channel.
Basic Parameterisation
The basic parameters such as deadband and motion
inhibit time can be set using either the GSD file or a suitable PDM or
FDT utility. The default settings will be suitable for most systems. Both
channels will adopt the same settings.
Parameterisation can only be carried out on the Primary channel.
IDATA4 Bit 5 indicates the channel status and will show if the channel
in communication is the Primary or Backup.
Fig 34: Flying Redundancy
– One highway redundancy
FR
Primary
Backup
Profibus Card
address # =n
address # = 64+n
Master PLC Standby PLC
Highway 1
