P94DVN01A
Installation
3.3 Electrical Installation
3.3.1 Cable Types
Due to the high data rates used on DeviceNet networks, it is paramount that correctly specified cable is used.
The use of low quality cable will result in excess signal attenuation and data loss. Several types of cable are
available for DeviceNet networks: flat cable, thicknet, mid cable and thinnet. Installation is typically done
with thicknet for trunk cable and thinnet for drop cable. Thicknet has a 3” minimum bend radius. Thinnet is
more flexible, with a 2” minimum bend radius, and as such is easier to install. Thinnet can be used for the
entire installation. The type of cable used, the lengths of the overall network and the drop cables all affect the
maximum baud rate.
Cable specifications and approved manufacturers are available from the official DeviceNet website at: http://
www.ovda.org.
3.3.2 Network Limitations
There are several factors that must be taken into consideration when designing a DeviceNet network. For full
details refer to the official “DeviceNet Planning and Installation Manual” available on the http://www.ovda.org
website. However, here is an abbreviated checklist:
DeviceNet networks are limited to a maximum of 64 nodes. Devices default to node 63 so leave node 63
open to avoid duplicate node addresses when adding devices.
Maximum total network length is governed by the data rate and cable type used. Refer to Table 3.
Table 3: Network Length, Drop Cable Length and Baud Rate
Data Rate
MAXIMUM Network Length
Sum of all Drop Cable Lengths
Flat Cable
Thicknet
Mid Cable
Thinnet
125 kbps
420m
500m
300m
100m
156m
250 kbps
200m
250m
250m
100m
78m
500 kbps
75m
100m
100m
100m
39m
Cumulative drop line does not exceed the network specified limit.
Network drops/spurs must not exceed 6 meters (19’ 8.2”).
Use fiber optic segments to:
Extend networks beyond normal cable limitations
Overcome different ground potential problems
Overcome very high electromagnetic interference
Ground at only one location, prferably in the center of the network.
•
•
•
•
•
•
•
•
•
