Emerson PACSystems RX3i User Manual page 216

PACSystems™ RX3i and RSTi-EP CPU Reference Manual
GFK-2222AK
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:
EGD Sweep Impact
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:
Scan 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.
CPU
CPU310/NIU001
CPU315/CPU320
CPE010
CPE020
CPE030
Serial I/O, SNP & RTU Protocols
= Consumption
Scan
= Exchange Overhead
EGD Exchange Overhead Time
Embedded Ethernet
Activity
Consume /
READ
Produce /
WRITE
Consume /
READ
Produce /
WRITE
Consume /
READ
Produce /
WRITE
Consume /
READ
Produce /
WRITE
Consume /
READ
Produce /
WRITE
+ Production
Scan
+ Byte Transfer Time
Rack-based Ethernet Module
Interface
(µs)
NA
NA
NA
NA
184.3
342.0
87.7
187.9
85.1
191.8
Appendix A
October 2019
(µs)
233.6
480.6
100.0
195.1
238.2
452.0
117.8
257.5
114.1
253.5
208