Appendix A. Performance Data
290
PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual
GFK-2222AD
A-3.6
EGD Sweep Impact for Embedded Ethernet Interface on RX3i &
RSTi-EP CPE Models
EGD Sweep Impact for RX3i CPE330 and CPE400
The CPE330 and CPE400 process Ethernet communications independently from logic and sweep
execution. This architecture precludes the possibility of Ethernet communications causing the watchdog
timer to time out. Consequently, the discussion below does not apply to CPE330 or CPE400.
EGD Sweep Impact for RX3i CPE302/CPE305/CPE310 and RSTi-EP CPE100/CPE115
Embedded Ethernet Interface
Each EGD production or consumption will take about 200 µs regardless of size of exchange. For Produced
Exchanges on the embedded port you can think of it as a timed interrupt block that takes 200µs duration
to execute each time it is triggered. For Consumed Exchanges on the embedded port you can think of it
as an I/O interrupt block that takes 200µs duration to execute each time the remote unit sends an
exchange and it is received on the embedded port.
It is important to note that this 200µ
s per exchange is not a simple ‘sweep impact’ time, rather per
execution of that exchange time, and depending on sweep time length and production period it may
occur more than one time per sweep.
Users configuring systems with EGD on an embedded Ethernet port should take care to make sure that
production and consumption time on the embedded Ethernet port is accounted for.
The impact of EGD Exchanges configured on Embedded Ethernet Interface of RX3i CPE302/CPE305
/CPE310 and RSTi-EP CPE100/CPE115 on the Controller sweep can be reflected in two parameters:
1.
𝑻𝒐𝒕𝒂𝒍_𝑬𝒈𝒅𝑰𝒎𝒑𝒂𝒄𝒕𝑷𝒆𝒓𝑾𝑫𝑻_𝒎𝒔
:
This is the total EGD impact per Watchdog Time period
configured in milliseconds (ms).
2.
𝑬𝒈𝒅𝑷𝒓𝒐𝒄𝒆𝒔𝒔𝒐𝒓𝑼𝒕𝒊𝒍𝒊𝒛𝒂𝒕𝒊𝒐𝒏 %
:
This is the percentage EGD processor utilization.
The formula for calculating these two parameters are shown below:
𝑇𝑜𝑡𝑎𝑙_𝐸𝑔𝑑𝐼𝑚𝑝𝑎𝑐𝑡𝑃𝑒𝑟𝑊𝐷𝑇_𝑚𝑠 = ∑ (
𝑊𝑑𝑡_𝑚𝑠
𝑃𝑒𝑟𝑖𝑜𝑑_𝑚𝑠
𝑛
× 𝐸𝑥𝑐ℎ𝑎𝑛𝑔𝑒𝑃𝑟𝑒𝑠𝑒𝑛𝑡
𝑛
× 0.2 00)
255
𝑛=1
𝐸𝑔𝑑𝑃𝑟𝑜𝑐𝑒𝑠𝑠𝑜𝑟𝑈𝑡𝑖𝑙𝑖𝑧𝑎𝑡𝑖𝑜𝑛_% = (
𝑇𝑜𝑡𝑎𝑙_𝐸𝑔𝑑𝐼𝑚𝑝𝑎𝑐𝑡𝑃𝑒𝑟𝑊𝐷𝑇_𝑚𝑠
𝑊𝑑𝑡_𝑚𝑠
) × 100
𝑊𝑑𝑡_𝑚𝑠
–
Watchdog time configured in ms
𝑃𝑒𝑟𝑖𝑜𝑑_𝑚𝑠
𝑛
–
Exchange Period n
th
Exchange, as configured in ms (Production Period for production
exchanges and Consumption timeout for consumption exchanges
𝐸𝑥𝑐ℎ𝑎𝑛𝑔𝑒𝑃𝑟𝑒𝑠𝑒𝑛𝑡
𝑛
–
n
th
Exchange configured (value=1) or not configured (value=0)
It is recommended that the calculated
𝑬𝒈𝒅𝑷𝒓𝒐𝒄𝒆𝒔𝒔𝒐𝒓𝑼𝒕𝒊𝒍𝒊𝒛𝒂𝒕𝒊𝒐𝒏_%
for a given EGD exchange
configuration and Watchdog period should be less than 50-55% for stable operation within watchdog
period without WDT elapse.
Note:
The higher percentage of this parameter indicates that the EGD on Embedded Ethernet
interface could have a greater impact on CPU applications.