Rockwell Automation MD65 Profibus Communication Card User Manual
Page 63
Using Multi-Drive Mode
8-3
The multiple drive connectivity, up to five drives with at least one
MD65 drive, for example, one MD65 and four MD60 drives, provides
a low cost Profibus solution in the industry for multiple drives.
Important:
In Multi-Drive mode, the unit will not operate with MDI
peripheral devices such as the OIM or the MDCOMM-
232 and the application of any other peripheral will be
prohibited.
Benefits of Multi-Drive mode include:
•
Lower hardware costs. Only one MDCOMM-PBUS module is
needed for up to five drives. The MD60 can also be used for the
daisy-chained drives instead of MD65 drives.
•
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 means to put MD60 drives on Profibus (MD60 drives
do not have an internal communications module slot).
•
Controller can control, monitor, and read/write parameters for all
five drives.
The trade-offs of Multi-Drive mode include:
•
If the MD65 drive with the MDCOMM-PBUS module 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
mode). This is because the MDCOMM-PBUS module must take
the Profibus data for the other drives and sequentially send the
respective data to each drive over RS-485.
•
Since the RS-485 ports are used for daisy-chaining the drives,
there is no connection for a peripheral device such as an OIM.
The AK-U0-RJ45-SCI MDI Splitter Cable cannot be used to add a
connection for a peripheral device.