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Chapter
5
Operating Instructions
Flexi Soft Gateways
56
© SICK AG • Industrial Safety Systems • Germany • All rights reserved
8012664/XB29/2013-06-11
Subject to change without notice
Ethernet gateways
Once a connection has been successfully created, data can then be exchanged between
the PLC and the EtherNet/IP gateway.
The connection will remain open until it is closed by either the PLC or the EtherNet/IP
gateway.
Packet update interval
The packet update interval for Class 1 connections that will be returned to the EtherNet/IP
PLC in the Forward Open response depends on the following factors:
the value for the
Requested Packet Interval
received from the EtherNet/IP PLC in the
Forward Open message
the
Maximum PLC Update Rate
as configured in the
Gateway configuration
dialog of
the Flexi Soft Designer
the 10 ms system clock that the EtherNet/IP gateway operates on
If the Requested Packet Interval is less than the Maximum PLC Update Rate, the packet
update interval will be set to the Maximum PLC Update Rate. Otherwise, it will be set to the
Requested Packet Interval.
If the packet update interval is not a multiple of 10 ms (10, 20, 30, 40, etc.), then the
packet update interval will be adjusted up to the next multiple of 10 ms.
Requested
Packet Interval
Maximum PLC
Update Rate
Actual packet
update interval
Description
5 ms
10 ms
10 ms
Set to Maximum PLC Update Rate
10 ms
10 ms
10 ms
Requested Packet Interval accepted
15 ms
20 ms
20 ms
Set to Maximum PLC Update Rate
15 ms
10 ms
20 ms
Requested Packet Interval adjusted
upward to 20 ms
20 ms
25 ms
30 ms
Maximum PLC Update Rate adjusted
upward to 30 ms
40 ms
30 ms
40 ms
Requested Packet Interval accepted
32 ms
30 ms
40 ms
Requested Packet Interval adjusted
upward to 40 ms
48 ms
40 ms
50 ms
Requested Packet Interval adjusted
upward to 50 ms
50 ms
40 ms
50 ms
Requested Packet Interval accepted
Bandwidth limitations
The maximum number of Class 1 messages per second is limited by the FX3-CPUx. At 50 %
of available CPU bandwidth, this is approximately 200 messages per second or one
Class 1 connection at 10 ms I/O update rate (the system clock frequency of the FX0-GENT
is 10 ms).
PLC update rate [ms]
Cyclic two-way I/O
connections
Cyclic input-only multicast
connections
10 1 2
20 2 4
40
Up to 4
Up to 8
The gateway will not enforce these bandwidth recommendations. However, if the band-
width used for Class 1 communication exceeds 200 messages per second, the RS-232
interface and the Ethernet TCP/IP interface will slow down.
Tab. 30: Examples for the
packet update interval
Tab. 31: Recommended
bandwidths for Class 1
messages
Note