Some of the events that can cause a switchover are:

•Hardware failure within the active controller

•Communications failure between the active controller and I/O

•Communications failure on both control network ports of the

active controller

•Removal of the active controller from the carrier

•User request initiated from Diagnostic Explorer

System Compatibility

M-series, S-series and SZ controllers are all supported on

DeltaV v12.3 and beyond. PK Controllers are supported on

DeltaV v14.3 and beyond. For detailed version compatibility

see the Prerequisites section below.

Redundant controller pairs must be of the same series. For

example, M-series and S-series controllers cannot be connected

together as a redundant pair.

Although an SX controller can operate as a standby controller to an

SQ active controller, it is recommended that both the active and

standby controllers be of the same hardware. The SQ may not have

sufficient memory or CPU capacity to accept the configuration that

runs in an SX controller. This applies for MX and MQ controllers as

well, only mix controller types as a temporary condition during a

hardware upgrade.

The MQ, MX, SQ, SX and PK Controllers are all capable of

redundancy. For more information on these controllers, refer to

the respective controller product data sheet.

SZ Controllers are also capable of redundancy. For more

information on this controller, refer to the DeltaV SIS Electronic

Marshalling or DeltaV SIS IS Electronic Marshalling product data sheets.