Precautions - Mitsubishi Electric MELSEC iQ-RD77MS2 User Manual

Precautions

Addition of slave stations
Do not connect 121 or more slave stations. If a slave station is added to a system having 120 slave stations, all stations will
fail and data link cannot be performed.
• Whether the number of the connected slave stations exceeds the controllable number can be checked
using "Number of connected modules over occurrence status" (SB0099). Number of connected modules
detected by "Number of connected modules over occurrence status" (SB0099) is the total of the slave
stations which are currently connected and the disconnected stations (slave stations which were previously
connected).
• The number of stations which were previously connected can be cleared by executing the network map
update of the CC-Link IE Field Network diagnostics. (MELSEC iQ-R Simple Motion Module User's
Manual (Network))
• A data link error may momentarily occur in all the stations and outputs of the connected slave stations may
turn off since all stations on the network will be reconnected when executing the network map update. Set
output data if needed. (Page 52 Output hold when a data link error occurs)
Connecting/disconnecting a cable and powering off/on a device
If the following operations are performed, the actual network configuration and the network map of the CC-Link IE Field
Network diagnostics may be a mismatch. Whether mismatch is occurred or not can be checked using "Network configuration
mismatch occurrence status" (SB0098).
In addition, if the following operations are performed, an alarm (communication error) may occur in the station in which the
synchronization communication is performed or a data link error may momentarily occur in all the stations and outputs of the
connected slave stations may turn off. An operation cycle time over error or an inter-module synchronization cycle over error
may be detected in the Simple Motion module. Check parameters related to output hold setting, inter-module synchronization
cycle, and alarm detection for slave stations again if needed.
Network configuration
Star topology
Line topology
The actual network configuration and network map can be matched by executing the network map update of
the CC-Link IE Field Network diagnostics. (MELSEC iQ-R Simple Motion Module User's Manual
(Network))
A data link error may momentarily occur in all the stations and outputs of the connected slave stations may
turn off since all stations on the network will be reconnected when executing the network map update. Set
output data if needed. (Page 52 Output hold when a data link error occurs)
Operation
• Powering off and on a slave station or switching hub
• Connecting/disconnecting an Ethernet cable connected to the switching hub
• Disconnecting an Ethernet cable from a slave station and connecting it to another slave station or a switching hub
• Disconnecting more than 9 stations, or half the number of slave stations or more in the system
• Changing the network topology when adding a slave station
• Simultaneously powering off/on multiple stations
• Simultaneously connecting/disconnecting Ethernet cables to/from multiple stations (When a data link faulty station
returns, a data link error will occur in all the stations.)
• Disconnecting more than 9 stations, or half the number of slave stations or more in the system
• Changing the network topology when adding a slave station
5 NETWORK CONFIGURATION OF RD77GF
5.1 CC-Link IE Field Network Configuration
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