Yaskawa SmartTrac DeviceNet Card - Manual (Page 12)

SMART TRAC DeviceNet Card
8
••
DeviceNet Basics Technical Manual 3554-0070
System Features: Removal and replacement of devices from the
network under power.
When using a combination of thin and thick cable in a DeviceNet network,
calculate the maximum cable distance according to Figure 4 and the following
formulae:
At 125 Kbps: L
thick
+ 5.0 * L
thin
= 500
At 250 Kbps: L
thick
+ 2.5 * L
thin
= 250
At 500 Kbps: L
thick
+ L
thin
= 100
(L
thick
is length of thick cable and L
thin
is length of thin cable)
Length of Thin
Cable (meters)
Length of Thick Cable (meters)
100
80
60
40
20
200 100 300 400 500 0
0
500
Kbps
250
Kbps
125
Kbps
Figure 4. Combined Thin and Thick Cable Length Determination
Thick cable consists of two shielded pairs twisted on a common axis with a
drain wire in the center. An overall braid shield covers the shield pairs. Thick
cable is typically used for trunk lines.
The thick cable specified for DeviceNet network connections consists of:
•
One (1) twisted signal pair (#18): blue/white
•
One (1) twisted power pair (#15): black/red
•
Separate aluminized Mylar shields around power pair and signal pair
•
Overall foil/braid shield with drain wire (#18): bare
Thinner and more flexible than than Thick Cable, use Thin Cable for drop lines
or for shorter distance trunk lines.
The thin cable specified for DeviceNet network connections consists of:
•
One twisted signal pair (#24): blue/white
•
One twisted power pair (#22): black/red
•
Separate aluminized Mylar shields around power pair and signal pair
•
Overall foil/braid shield with drain wire (#22): bare
Line Length with both
Thick and Thin Cables
Thick Cable
Specifications
Thin Cable
Specifications