Bronkhorst DeviceNet slave interface - Manual (Page 10)

BRONKHORST ®
Page 10 DeviceNet interface 9.17.026
The distance between any two points must not exceed the maximum cable distance allowed for the data rate used.
Data rate
Maximum distance
(flat cable)
Maximum distance
(thick cable)
Maximum distance
(mid cable)
Maximum distance
(thin cable)
125k bit/s 420m 500m 300m 100m
250k bit/s 200m 250m 250m 100m
500k bit/s 75m 100m 100m 100m
2.5 D ROP LINES WITH D EVICE N ET
The cumulative drop line length refers to the sum of all drop lines, thick, thin, or mid cable, in the cable system. This
sum cannot exceed the maximum cumulative length allowed for the data rate used.
Data rate Cumulative drop line length
125k bit/s 156m
250k bit/s 78m
500k bit/s 39m
The maximum cable distance from any device on a branching drop line to the trunk line is 6m.
2.6 N ETWORK TERMINATION
You must terminate the trunk line at both ends with 121 Ohms, 1%, 1/4W terminating resistors.
2.7 P OWER S UPPLY
The cable system requires the power supply to have a rise time of less than 250 milliseconds to within 5% of its rated
output voltage. You should verify the following:
 The power supply has its own current limit protection
 Fuse protection is provided for each segment of the cable system
 Any section leading away from a power supply must have protection
 The power supply is sized correctly to provide each device with its
 Required power
 De‐rate the supply for temperature using the manufacturer’s guidelines
Use the power supply to power the DeviceNet cable system only. If a device requires a separate 24V
power source other than the DeviceNet power source, you should use an additional 24V power source.
Choosing a Power Supply
The total of all of the following factors must not exceed 3.25% of the nominal 24V needed for a DeviceNet system.
initial power supply setting
1.00%
line regulation 0.30%
temperature drift (total) 0.60%
time drift 1.05%
load regulation 0.30%
The maximum cable distance is not necessarily the trunk length only. It is the maximum distance
between any two devices.