Rockwell Automation 22-COMM-C ControlNet Adapter - Manual (Page 71)

Using Multi-Drive Mode 7-3
Benefits of Multi-Drive mode include:
• Lower hardware costs. Only one adapter is needed for up to five
drives. Any PowerFlex 4-Class drive can be daisy-chained.
• Reduces the network node count. 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 convenient way to put more than one PowerFlex 4 drive on
the network using only one adapter (PowerFlex 4 drives do not have
an internal communications adapter slot).
• Controller can control, monitor, and read/write parameters for all five
drives.
Trade-offs of Multi-Drive mode include:
• When a PowerFlex 40/400 drive with an internal-mounted adapter is
powered down, communications with the daisy-chained drives is
disrupted and the drives will take the appropriate communications
loss action set in each drive. However, communications will not be
disrupted when the adapter is used in a DSI External Comms Kit and
a daisy-chained drive is powered down.
• Communications throughput to the daisy-chained drives will be
slower than if each drive was a separate node on the network (Single
mode). This is because the adapter must take the network 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 in
Multi-Drive mode is:
• Since the RS-485 ports are used for daisy-chaining the drives, there is
no connection for a peripheral device such as a HIM. The
AK-U0-RJ45-SC1 DSI Splitter cable cannot be used to add a second
connection for a peripheral device.
Adapter Mounted In
Drives per
Node Additional Throughput
Time versus Single Mode
PowerFlex 40/400 or
DSI External Comms
Kit
1 drive 0 milliseconds
2 drives +24 milliseconds
3 drives +48 milliseconds
4 drives +72 milliseconds
5 drives +96 milliseconds