Omron SYSMAC CS1D-PD Series Operation Manual page 32

Application Precautions
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• When replacing a Duplex Unit online in a Duplex CPU, Dual I/O Expan-
sion System, always follow the procedure provided in this operation man-
ual.
• When replacing a Connecting Cable or Expansion Unit online in a Duplex
CPU, Dual I/O Expansion System, always follow the procedure provided
in this operation manual.
• When using duplex Connecting Cables in a Duplex CPU, Dual I/O Expan-
sion System, always use cables that are the same length.
• In a Duplex CPU, Dual I/O Expansion System, do not connect two Con-
necting Cables to Expansion Backplanes that are in different operating
levels. Doing so may cause improper operation.
• Before removing a Unit during operation without a PLC Programming
Device (CX-Programmer or a Programming Console), always confirm that
the Removal of a Unit without a Programming Device or Removal/Addi-
tion of Units without a Programming Device function is enabled in the PLC
Setup. If a Unit is removed while the PLC Setup is not set to enable Unit
removal without a Programming Device, an I/O bus error will occur and
the PLC (CPU Unit) will stop operating.
• When a Unit has been removed during operation without a PLC Program-
ming Device (CX-Programmer or a Programming Console), data trans-
ferred from the removed Unit to the CPU Unit may be invalid. If an invalid
data transfer will adversely affect the system, use a Programming Device
to replace the Unit online.
• When the Removal of a Unit without a Programming Device or Removal/
Addition of Units without a Programming Device function is enabled in the
PLC Setup and a Special I/O Unit has been removed, the Special I/O Unit
Area words allocated to that Unit for data transfer (to and from the CPU
Unit) will be cleared. If the loss of the Special I/O Unit Area data will
adversely affect the system, disable these functions in the PLC Setup and
use a Programming Device to replace the Unit online. (When a Program-
ming Device is used to replace the Unit online, the data in the Special I/O
Unit Area is retained while the Unit is removed.)
• An I/O bus error, which can be caused by a Unit malfunction, is normally a
fatal error that stops operation. When he Removal of a Unit without a Pro-
gramming Device or Removal/Addition of Units without a Programming
Device function is enabled in the PLC Setup, the I/O bus error will be
treated as a non-fatal error and PLC (CPU Unit) will not stop operating. If
there are any Units that will adversely affect the system if an I/O bus error
occurs, do not enable these functions in the PLC Setup.
• Do not turn ON the Maintenance Start Bit (A80015) continuously from the
ladder program. As long as the Maintenance Start Bit is ON, errors will not
be generated even if there are Unit malfunctions, so the system may be
adversely affected.
Note The Maintenance Start Bit is provided to prevent non-fatal errors
from occurring during Unit removal without a Programming Device.
• Do not turn ON the Online Replacement Completed Bit (A80215) continu-
ously from the ladder program. If the Unit is mounted while the Online
Replacement Completed Bit is ON, the PLC (CPU Unit) may stop operat-
ing.
Note The Online Replacement Completed Bit is provided to restart the
data exchange between the replaced Unit and CPU Unit. After a
Unit has been replaced without a Programming Device, turn ON
the Online Replacement Completed Bit to restart the data ex-
change.
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