Delta RMC151 - Manual (Page 481)

6 Communication
• Read Rockwell Automation’s EtherNet/IP Performance application guide
(Publication ENET-AP001D-EN-P). It covers this subject in greater detail.
Considerations for RMC EtherNet/IP Performance
The RMC can support EtherNet/IP at its enforced minimum RPIs without compromising its
determinism with respect to motion control or EtherNet/IP I/O communications.
Considerations for Master EtherNet/IP Performance
The PLC EtherNet/IP I/O module must often support a large number of devices, including
RMCs and other devices. Therefore, it is important to recognize the limits in bandwidth of
your EtherNet/IP master controller, and to know how to determine the amount of
bandwidth being utilized. This entire subject is covered in more detail in Rockwell
Automation’s EtherNet/IP Performance application guide (Publication ENET-AP001D-
EN-P), but will be addressed narrowly here for RMC connections.
Here are some published bandwidth limits for EtherNet/IP I/O controllers available as of
this writing:
Manufacturer Module Total Bandwidth (packets/second)
Allen-Bradley 1756-ENET/B (obsolete) 900
Allen-Bradley 1756-ENBT 5000
Allen-Bradley 1756-EN2T,
1756-EN2TR,
1756-EN2F,
1756-EN2TXT,
1756-EN3TR, 10000
Allen-Bradley 1768-ENBT 5000
Allen-Bradley 1769-L23E 2000
Allen-Bradley 1769-L3xE 4000
Allen-Bradley 1788-ENBT 4000
Schneider Electric Quantum 140 NOC 711 00 7500
Schneider Electric Premium TSX ETC 100
7500
Omron CS1W-EIP21 6000
Omron CJ1W-EIP21 6000
Omron CJ2H-CPUxx-EIP 6000
Omron CJ2M-CPU3x 3000
Notice that it is recommended that not more than 90% of this bandwidth be used on I/O
connections.
The bandwidth required for each RMC depends on the RPI and the number of connections.
The first connection requires 2 / RPI packets per second (where RPI is in seconds), and
each additional connection requires 1 / RPI additional packets per second. The following
chart summarizes the requirement:
Number of Connections Required Bandwidth (packets/second)
1
2 / RPI
2 3 / RPI
3 4 / RPI
4 5 / RPI
Therefore, to determine the total bandwidth required for any group of RMCs being
serviced by a single master EtherNet/IP I/O controller, simply add up the bandwidth
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