146
SI-Ethernet User Guide
Issue: 3
7.3.1
RTMoE Message rate capability
When designing a network, the message loading for each device should be checked to ensure the
number of messages do not exceed the maximum recommended value.
Consider the following example where a Unidrive M700 is communicating with three other devices
over Ethernet using Modbus TCP/IP (10 parameters read every 100 ms), EtherNet/IP (5
parameters read every 10 ms and 5 parameters written every 10 ms) and RTMoE (2 parameters
written every 500 µs).
7.3.2
RTMoE Message type
From the system design, it should be known how many drives will be used and what data needs to
be sent where. There are two fundamental ways of sharing data:
•
Cyclic data – use cyclic links for important information relating to the dynamic behavior of
the machine (e.g. control word, speed reference, etc.)
•
Non-cyclic data – used for non time-critical information (e.g. drive setup data) A user
program must be used to control the transfer of non-cyclic messages. (see
Non cyclic
enable
(
S.02.035
) and
Non cyclic
base parameter
(
S.02.036
))
Each cyclic message can be one of three types:
Protocol
Number of
Parameters
Rate
Parameters accessed /
second
Message rate /
second
Modbus TCP/IP
10 x read
100 ms
100
10
EtherNet/IP
5 x read
10 ms
500
100
5 x write
10 ms
500
100
RTMoE
2 x write
500 µs
4000
2000
Total
5100
2210
Maximum supported
6000
8000
Within capability?
1
Unicast – used if data needs to go
from one device to another
2
Broadcast – used if data needs to go
from one device to all other devices
3
Multicast – used if data needs to go
from one device to a subset of the other
devices
Содержание Unidrive M600
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