4-11
4 Remote I/O Master Communications
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
4-2 Scan List
4
4-2-1 Scan List
4-2 Scan List
A scan list is used to register the slaves with which the Master Unit communicates in DeviceNet remote
I/O communications. It is the basis on which the Master Unit communicates with slaves.
The Master Unit does not contain a scan list by default. DeviceNet Unit, however, has a default setting
that allows it to communicate with all slaves even with the scan list disabled, but this operating mode
should not be used for normal operation. Always create a scan list prior to operating the Unit.
z Scan List Contents
The contents of the scan list is listed in the following table. When a Master Unit goes online, it com-
pares each of these items with the slaves that are actually connected to the network. The items that
are compared, however, will depend on the allocation method that is used.
4-2-1 Scan List
Item Description Fixed allocations User-set allocations
using device vari-
ables for CJ-series
Unit
User-set allocations
from the CX-Integra-
tor
Node address Node address for
every Slave
Compared Compared
Allocated IN/OUT
sizes and allocation
Settings of the num-
ber of bytes allocated
to every slave in a
data area of the Mas-
ter Unit
Compared Compared
Vendor Unique manufacturer
ID
Not compared Set from CX-Integra-
tor
Device type Unique product type
value
Not compared Set from CX-Integra-
tor
Product code Unique product model
value
Not compared Set from CX-Integra-
tor
Connection type Applicable DeviceNet
protocol
(See A-2 DeviceNet
Connections for
details.)
Automatically set Automatically set or
set from CX-Integrator
Connection path Type of slave I/O data
(See A-2 DeviceNet
Connections for
details.)
Cannot be set Set from CX-Integra-
tor
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