Ethernet Global Data Sweep Impact - GE PACSystems RX7i Reference Manual

A-3.5

Ethernet Global Data Sweep Impact

Note: Refer to Section, A-3.6 for information on standalone models supporting Embedded Ethernet
interface.
Depending on the relationship between the CPU sweep time and an Ethernet Global Data (EGD)
exchange's period, the exchange's data may be transferred every sweep or periodically after some
number of sweeps. Therefore, the sweep impact varies based on the number of exchanges that are
scheduled to be transferred during the sweep. All 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 + 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.
CPU
CPE302/CPE305/CPE310/
CPE330/CPE400
CPU310/NIU001
CPU315/CPU320
CPE010
CPE020
CPE030
CPE040
101
EGD Class 1 for this CPU type requires RX3i CPE310/CPE302/CPE305 firmware version 8.30 or later. Prior to that, EGD was
only possible in RX3i via the ETM001 module. Refer to the Section, A-3.6..
102
Performance data not available for this release.
GFK-2222AD
= Consumption
Scan
EGD Exchange Overhead Time
Embedded Ethernet Interface
Activity
Consume / READ
Produce / WRITE
Consume / READ
Produce / WRITE
Consume / READ
Produce / WRITE
Consume / READ
Produce / WRITE
Consume / READ
Produce / WRITE
Consume / READ
Produce / WRITE
Consume / READ
Produce / WRITE
April 2018
+ Production
Scan
(µs)
101
—
101
—
NA
NA
NA
NA
184.3
342.0
87.7
187.9
85.1
191.8
35.08
75.16
Appendix A. Performance Data
Rack-based Ethernet Module
(µs)
102
—
—
233.6
480.6
100.0
195.1
238.2
452.0
117.8
257.5
114.1
253.5
47.12
103.0
287