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Starting Communications Section 2-4
2-4-2 Starting the System
Turn ON the communications power supply and the power to other nodes in
the following order.
1,2,3... 1. Turn ON the communications power supply.
2. Turn ON the power to each Slave.
3. Turn ON the power to the Master Unit.
Note The power supplies listed above can all be turned ON simultaneously. The
external I/O power supply can be turned ON at any time.
2-4-3 Creating and Registering Scan Lists
Scan lists are lists that register the information that is transferred between
Master Units and Slaves. The Master Unit compares the scan list with the sta-
tus of the Slave currently being communicated with, so communications with
the Slave are always being checked.
For details on scan lists and remote I/O communications, refer to the opera-
tion manual for the Master Unit.
Note When a scan list is disabled, communications are possible with all Slaves on
the DeviceNet Network with fixed allocations. Without scan lists, however, the
Master Unit cannot check if there is an error in a Slave.
For normal operations, always enable the scan lists.
Precautions
User I/O Allocations The user can allocate any words for Slave I/O for the DeviceNet I/O Areas (IN
Area, OUT Area) in the Master Unit.
When user allocations are used, scan lists must be created with a DeviceNet
Configurator and registered in the Master Unit. The scan list is enabled as
soon as it is registered, and remote I/O communications start according to the
scan list.
For details, refer to the DeviceNet Operation Manual (W267) and the
DeviceNet Configurator Operation Manual (W328).
Fixed I/O Allocations Slave I/O is allocated in the DeviceNet I/O area (IN Area, OUT Area) in the
Master Unit in the same order as the Slave node addresses.
When fixed allocations are used, the scan lists are automatically created and
registered using the Master Unit's software switches. The scan list is enabled
as soon as it is registered, and remote I/O communications start according to
the scan list. When scan list is enabled, the mode is called the scan list-
enabled mode.
The registered scan lists can be cleared using the software switches. When
scan lists are cleared (disabled), the mode is called the scan list-disabled
mode.
Creating and
Registering Fixed
Allocation Scan Lists
The method of creating and registering scan lists for fixed allocation using
Programming Console and a CS/CJ-series Master Unit is explained here. For
details on operating Peripheral Devices, refer to the operation manual for the
Peripheral Device being used with the PLC. For details on creating scan lists,
refer to the operation manual for the Master Unit.
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