Mitsubishi Electric QJ71E71-100 User Manual page 69

(2) Mounting an E71 on the extension base unit of a redundant system
This section provides information on mounting an E71 on the extension base unit of a redundant system.
(a) System configuration
The following shows the system configuration.
Control system
Extension cable
(b) Restrictions on the use of the functions
Restrictions are the same as those of when an E71 is mounted on a main base unit, except for the following
restrictions.
• Because an E71 does not issue a system switching request to the control system CPU module, the
system switching does not continue communications. To continue communications even when the E71
experiences a communication error or when the cable is disconnected, mount the E71 on a main base
unit.
• Dedicated instructions cannot be used. To use dedicated instructions, mount the E71 on a main base unit.
• The following restrictions apply to communications via modules mounted on an extension base unit.
• An access destination that can be specified (a control system CPU module or standby system
CPU module or a system A CPU module or system B CPU module) varies according to the MC
protocol dedicated command.
• If systems are switched during MC protocol communications or communications using dedicated
instructions from other stations, a communication timeout may occur.
Standby system
Tracking cable
Extension base unit
Ethernet
Connected device
CHAPTER 5 SYSTEM CONFIGURATION
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