Rockwell Automation 25-COMM-P PowerFlex PROFIBUS DPV1 Adapter - Manual (Page 56)

56 Rockwell Automation Publication 520COM-UM004A-EN-E - November 2013
Chapter 7 Using Multi-Drive Mode
Multi-Drive Mode Example for Network
Benefits of Multi-drive mode include:
• Lower hardware costs. No need to purchase additional communication
adapters for daisy-chained drives.
• Reduces the network node count. For example, in Single-drive mode 30
drives would consume 30 nodes. In Multi-drive mode, 30 drives can be
connected in 6 nodes.
• Controller can control, monitor, and read/write parameters for all five
drives.
The trade-offs of Multi-drive mode include:
• If the PowerFlex 520-series drive with 25-COMM-P adapter is powered
down, then communications with the daisy-chained drives is 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 PROFIBUS (Single-drive mode).
This is because the 25-COMM-P adapter must take the PROFIBUS 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:
IMPORTANT For the examples in the chapter, we will use the PowerFlex 525 as a master
drive with four daisy-chained PowerFlex 4M drives.
Drive Additional Throughput Time
versus Single-Drive Mode
PowerFlex 525 0 ms
PowerFlex 525 plus 1 drive +24 ms
PowerFlex 525 plus 2 drives +48 ms
PowerFlex 525 plus 3 drives +72 ms
PowerFlex 525 plus 4 drives +96 ms
Esc Sel
Up to 5 drives per node
PROFIBUS
Up to four daisy-chained PowerFlex drives
(PowerFlex 4M shown)
RS-485 cable
PowerFlex 525
with
25-COMM-P as
master drive
AK-U0-RJ45-TB2P connector with
terminating resistor (120
Ω
)
AK-U0-RJ45-TB2P connector with
terminating resistor (120
Ω
)
AK-U0-RJ45-TB2P