Valid Memory Types For Ethernet Global Data; Planning Exchanges; Figure 34: Adding Symbolic Reference To Ethernet Global Data Exchange - GE RX3i User Manual

Chapter 5. Ethernet Global Data

Valid Memory Types for Ethernet Global Data

The PLC memory types listed below can be included in EGD exchanges.
Memory Type
%R
%W
%AI
%AQ
%I
%Q
%T
%M
%SA
%SB
%SC
%S
%G
Symbolic Variables
Discrete point references such as %I or %Q are configured as Byte-Array, Word-Array, or Dword-Array
variables. That means a variable with discrete point references must be defined in blocks of 8 points if it is
defined as a Byte-Array, 16 points if Word-Array, and 32 points if Dword-Array. Discrete memory must be byte-
aligned.
Boolean type and Boolean-Array variables are not allowed.
To use a symbolic variable in an EGD exchange, it must exist in the Variables definition for the target. To add it
to an exchange, double click the Variable field to open a selection dialog box.
Figure 35: Adding Symbolic Reference to Ethernet Global Data Exchange

Planning Exchanges

It is possible to configure more Ethernet Global Data than a PLC can transfer (especially on 10Mbit networks). If
high levels of consumer timeouts occur in some or all of the consumed exchanges, the EGD load can be
reduced by:
▪
Increasing the production period (especially if the period is more frequent than double the minimum time in
which the data is needed).
▪
Defining fewer exchanges, each with more data.
72 PACSystems* RX7i & RX3i TCP/IP Ethernet Communications User Manual
Description
Register memory in word mode
Word memory in word mode
Analog input memory in word mode
Analog output memory in word mode
Discrete input memory in byte mode
Discrete output memory in byte mode
Discrete temporary memory in byte mode
Discrete momentary memory in byte mode
Discrete system memory group A in byte mode
Discrete system memory group B in byte mode
Discrete system memory group C in byte mode
Discrete system memory in byte mode
Discrete global data table in byte mode
Symbolic variables
P-Producer
C-Consumer
P/C
P/C
P/C
P/C
P/C
P/C
P/C
P/C
P/C
P/C
P/C
P
P/C
P/C
GFK-2224Q