PACSystems™ RX3i and RSTi-EP CPU Reference Manual Appendix A
GFK-2222AK October 2019
Serial I/O, SNP & RTU Protocols 208
the exchanges must be taken into account when computing the worst-case sweep
impact.
The Ethernet Global Data (EGD) sweep impact has two parts, Consumption Scan and
Production Scan:
This sweep impact should be taken into account when configuring the CPU constant
sweep mode and setting the CPU watchdog timeout.
Where the Consumption and Production Scans consist of two parts, exchange overhead
and byte transfer time:
Exchange Overhead
Exchange overhead includes the setup time for each exchange that will be transferred
during the sweep. When computing the sweep impact, include overhead time for each
exchange.
Note: The exchange overhead times in the table below were measured for a test-case scenario of
1400 bytes over 100 variables.
EGD Exchange Overhead Time
Embedded Ethernet
Interface
(µs)
Rack-based Ethernet Module
(µs)
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