1-2
Section
DeviceNet Functions
6
1-2-3 DeviceNet (CompoBus/D) Communications Specifications
Item
Specification
Communications protocol
DeviceNet
Supported connections
(communications)
Master-Slave: Remote I/O and explicit messages
Peer-to-peer: FINS commands (see note 1)
Both conform to DeviceNet specifications
Connection forms (see note 2)
Combination of multi-drop and T-branch
connections (for trunk or drop lines)
Baud rate
500 kbps, 250 kbps, or 125 kbps (switchable)
Communications media
Special 5-wire cables (2 signal lines, 2 power
lines, 1 shield line)
Communications
distances
500 kbps
Network length: 100 m max. (see note 3)
Drop line length: 6 m max.
Total drop line length: 39 m max.
250 kbps
Network length: 250 m max. (see note 3)
Drop line length: 6 m max.
Total drop line length: 78 m max.
125 kbps
Network length: 500 m max. (see note 3)
Drop line length: 6 m max.
Total drop line length: 156 m max.
Communications power supply
24 VDC supplied externally
Max. number of nodes
64 nodes (including Configurator when used)
Max. number of Masters
Without Configurator: 1
With Configurator:
63
Max. number of Slaves
63 Slaves
Communications cycle time
(see note 4)
Without Configurator: Calculated from conditions
Ex:
Input Slaves (16-pt): 16
Output Slaves (16-pt) :16
Cycle time at 500 kbps: 9.7 ms
With Configurator: Set between 2 and 500 ms
Calculated value takes priority if longer.
Max. communications cycle
time with multiple Masters
(see note 5)
Calculated from conditions.
Ex:
Input Slaves (16-pt): 16
Output Slaves (16-pt) :16
Max. cycle time at 500 kbps: 18 ms
Error control checks
CRC error check
Note
1. FINS communications are not supported by the DeviceNet Interface Unit.
2. Terminating resistors are required at both ends of trunk line.
3. Indicates the length when thick cables are used. Reduce the network length
to 100 m max. when using thin cables. When using both thick and thin cables
together, refer to Combining Thick and Thin Cables in 3-2-2 Maximum Net-
work Length.
4. Indicates the maximum time for remote I/O communications from a Master
to a specific Slave until remote I/O communications are conducted again for
the same Slave.
5. The communications cycle time when more than one Master is present on a
single network.
Refer to the DeviceNet (CompoBus/D) Operation Manual (W267) for other com-
munications specifications, such as communications cycle times.