Rockwell Automation 22-COMM-D DeviceNet Adapter - Manual (Page 74)

7-2 Using Multi-Drive Mode
Figure 7.2 Multi-Drive Mode Example for Network
Benefits of Multi-Drive mode include:
• Lower hardware costs. Only one 22-COMM-D adapter is needed for
up to five drives. PowerFlex 4’s can also be used for the
daisy-chained drives instead of PowerFlex 40’s.
• Reduces the network node count (DeviceNet is 63 nodes maximum).
For example, in Single mode 30 drives would consume 30 nodes. In
Multi-Drive mode, 30 drives can be connected in 6 nodes.
• Provides a means to put PowerFlex 4’s on DeviceNet (PowerFlex 4’s
do not have an internal communications adapter slot).
• Controller can control, monitor, and read/write parameters for all five drives.
The trade-offs of Multi-Drive mode include:
• If the PowerFlex 40 with the 22-COMM-D adapter is powered down,
then communications with the daisy-chained drives are disrupted and
the drives will take the appropriate communications loss action set in
each drive.
• Communications throughput to the daisy-chained drives will be
slower than if each drive was a separate node on DeviceNet (Single
mode). This is because the 22-COMM-D adapter must take the
DeviceNet data for the other drives and sequentially send the
respective data to each drive over RS-485. The approximate
additional throughput time for Logic Command/Reference to be
transmitted and received by each drive is:
Drive
Additional Throughput Time
versus Single Mode
PowerFlex 40 w/22-COMM-D 0 ms
PowerFlex 40 w/22-COMM-D plus 1 drive +24 ms
PowerFlex 40 w/22-COMM-D plus 2 drives +48 ms
PowerFlex 40 w/22-COMM-D plus 3 drives +72 ms
PowerFlex 40 w/22-COMM-D plus 4 drives +96 ms
DeviceNet
up to 5 drives per node
PowerFlex 40
22-COMM-D
Up to 4 PowerFlex 4's or 40's
AK-U0-RJ45-TB2P
Connector w/3rd Party
Terminating Resistor
AK-U0-RJ45-TB2P
Connector w/3rd Party
Terminating Resistor
AK-U0-RJ45-TB2P RS-485