ABB AC 900F, Mounting And Installation Instructions Manual

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Section 2 Configuration Controller redundancy
M&I – AC 900F Controller 19
The S700 I/O modules are connected on the right side of the I/O bus, i.e. they are
simply plugged to the TU terminal blocks that were previously added to the CPU
modules. Up to ten I/O modules can be connected to the I/O bus of the CPU module.
The configuration in the Freelance Engineering hardware structure should
correspond to the actual controller configuration (local DIN rail). Make sure that
there are no blank TU terminal blocks between the individual I/O modules. I/O
modules connected on the right side of a gap (i.e. of a blank terminal block) are not
controlled by the CPU module.
Controller redundancy
Two controllers of identical configuration - hereinafter referred to as redundant
controllers - are used for redundant operation. While the active controller has the
“Primary“ status, the “Secondary“ status is assigned to the other controller. During
normal operation, the primary is the active controller and the secondary the passive
one (hot standby).
For synchronization purposes, a point-to-point Ethernet connection (100 MBit/s)
must be established between the controllers. This connection is also referred to as
redundancy link.
A redundant configuration may be composed of two controllers of basic or medium
level configuration. Make sure to use only the CI 930F, CI 910F or CI 773F
communication interface modules for the medium configuration level as only these
module types are suitable for redundant operation.
The S700 Direct I/O and the CM 772F communication module are not supported
with redundant controller arrangement.