ABB AC 800F - 4.3.3.2 Redundant Connection Via RS422 Interface; Fig. 4-61 Redundant Cabling of Two FI 820 F Via RS232 Interfaces

4 Cabling the AC 800F
4-84
Fig. 4-61 shows redundant cabling of two AC 800F with one serial fieldbus module
each, using channel 0.
Fig. 4-61 Redundant cabling of two FI 820F via RS232 interfaces
4.3.3.2 Redundant connection via RS422 interface
Note that only the primary unit is allowed to actively transmit data. The secondary unit
must set its interface to high resistance. Communication between the primary and the
secondary unit is not possible via this interface, since both their transmit signals and
their receive signals are linked to each other.
• Deactivate the internal termination of the serial fieldbus modules.
• Activate the external termination with external supply at the external TB 870F.
Connect an external 5 V power supply as seen in Fig. 4-54.
• Deactivate the termination of the internal terminal block.
• Link two redundant fieldbus modules FI 820F with the terminal block TB 870F
using cable TK 821F. Only hand-tighten the screws.
• Put on the TK 821F cable shields. Connect them to the two AC 800F contact
ledges using clips TV 83xF.
• Connect the appropriate interface on the terminal blocks TB 870F using the
terminals specified below, and establish a connection to the RS422 devices
(slaves). Use a twisted pair cable, e.g. 3 x 2 x 0.25 mm
2
.
• Observe the max. cable length of 1200 m.
• Apply the shield to terminal P of the terminal blocks.