Restrictions On System Configuration - Mitsubishi Electric MELSEC iQ-R Series Manual

2.2

Restrictions on System Configuration

This section describes the restrictions on the system configuration.
• When 'Online module change availability flag' (SM1616) of the CPU module or remote head module is OFF (0), the online
module change cannot be performed. Before performing the online module change, check that 'Online module change
availability flag' (SM1616) is ON (1). In the multiple CPU system, 'Online module change availability flag' (SM1616)
becomes ON (1) when all the CPU modules support the online module change. However, the setting details of the direct
change setting cannot be checked with 'Online module change availability flag' (SM1616). To check the direct change
setting, check the CPU parameter.
• In the multiple CPU system, the combined use of the Process CPU (with the setting to enable the direct change) and CPU
modules other than the Process CPU results in an error. ( MELSEC iQ-R Module Configuration Manual)
• When a module controlled by other CPU modules is accessed in the multiple CPU system, performing online module
change on the module causes the access to stop. The following shows the accesses to be stopped.
• FROM instruction
• Direct access input (DX)
• Instruction that uses a module access device (Un\G)
• Importing an input (X) or an output (Y)
• For the modules that are set to an empty slot in "I/O Assignment Setting" of the system parameters, online module change
is not permitted.
• For the modules that are set as the synchronous target module in "Inter-module Synchronization Setting" of the system
parameters, online module change is not permitted.
• Only direct change is available as a method of the online module change when a redundant system is configured using a
remote head module. The LEDs, SM/SD, and error codes can be checked with the control system remote head module.
2 SYSTEM CONFIGURATION
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2.2 Restrictions on System Configuration