
B-63404EN/03 CONNECTION 1.CONNECTING DeviceNet FUNCTIONS
- 75 -
NOTE
When Thick Cable Is Used Together With Thin
Cable
A mixture of thick cable and thin cable can be used
for the cable connecting furthermost nodes. Note,
however, that in this case, the line lengths of each
type of cable must satisfy the expression in the
following table. So, the total network length becomes
shorter than when the network is configured by
connecting only thick cable.
Prevent the maximum current consumption of the cables from being
exceeded.
Baud Rate Maximum Network Length
500 K bit/sec Lthick + Lthin < 100m
250 K bit/sec Lthick + 2.5 × Lthin < 250m
125 K bit/sec Lthick + 5 × Lthin < 500m
Lthick: Length of thick cable, Lthin: Length of thin cable
Example
Baud Rate Maximum Network Length
Acceptability
500 K bit/sec Lthick + Lthin=175 < 100m NG
250 K bit/sec Lthick + 2.5 × Lthin = 125 + 2.5 × 50=250 < 250m OK
125 K bit/sec Lthick + 5 × Lthin = 125 + 5 × 50 = 375 < 500m OK
According to the above calculation, communications at 250 kbit/sec
and 125 kbit/sec is possible in this case. Note, however, that a
network cannot be configured if the maximum allowable current
consumption of the cables is exceeded even if the above conditions
are satisfied.
Node
Node
Node
Node
Terminator
Terminator
T-branch tap
T-branch tap
Maximum network length
40m
Communications
power supply