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Important Product Information 5
GFK-1490C
When the PLC configuration is stored from an Ethernet PLC Programmer, the communications loss occurs immediately
after successful completion of the store. Attempts to store configuration plus logic and/or reference tables in one
operation can fail. However, storing configuration separately from logic or reference tables will always succeed.
Store of Program or Reference Tables to Flash May Cause Loss of Ethernet Communications
While storing the PLC program, configuration, and/or reference tables from PLC RAM memory into Flash memory,
Ethernet data communications may be lost. Normal data transfers are temporarily suspended during the Flash store
operation. Ethernet data transfers (such as used by an Ethernet PLC Programmer connection) during a Flash store
operation will fail when the Flash store exceeds the 10-second maximum period allowed for completion. Upon
completion of the store to Flash operation, normal operation will resume.
RUN Mode Program Store
A store of a folder containing large (greater than 14kb) program blocks from a PLC Programmer connected through the
Ethernet port on the CPU364, or through an IC693CMM321 Ethernet module, may fail and result in momentary loss of
communications. This condition has been observed only when attempting to store a large program to a PLC which is in
RUN mode, and which is configured to use a limited communications window. These conditions cause the store
operation to take the maximum possible period to complete. The failure may occur if this period exceeds 10 seconds for
an individual program block. If this problem does occur, one of the following options may be used to complete the
store operation successfully:
1.
Change the PLC configuration to use Run-to-Completion mode instead of a Limited Communications Window for
the store operation.
2.
Change the PLC from RUN to STOP mode to complete the store.
3.
Structure the folder being stored to eliminate large program blocks or subroutine blocks. This will minimize the
chance that any single block will take longer than the maximum 10-second period allowed for storage of that block.
Store of Large Program Blocks from Older Ethernet Programmers
If an attempt is made to store a folder which contains large (greater than 14kb) program blocks or subroutine blocks
using the IC693 MS-DOS programming software, Ethernet Version 6.6 or earlier, the store attempt may fail with the
message “(S83) Program size too large for PLC or invalid user program” displayed. If this problem is observed, the
following options may be used to complete the store operation successfully:
1.
Update the IC693 MS-DOS programming software, Ethernet Version, to a more recent version that can be run in a
DOS box under the Microsoft Windows NT/95 operating system. IC693 MS-DOS programming software,
Ethernet Version 9.02 or later is recommended. (Note: In order to configure the CPU364, Version 9.02 or later is
required.) This option requires Microsoft Windows NT or Microsoft Windows 95 to be installed on the PC that
executes the programming software.
2.
If the ladder contains large (greater than 14kb) program blocks or subroutine blocks, then restructure the ladder to
use smaller blocks, either by simplifying the program or by making use of more subroutine blocks that are each
smaller than 14kb in size.
3.
If neither of the previous options is practical, the following work-around for the problem may be successful.
Modify the CONFIG.SYS file on the MS-DOS programmer PC to decrease the maximum TCP segment size used
by the Beame & Whiteside driver. This may be accomplished by changing the values used on the line containing
the following:
DEVICE=C:\BWTCP\TCPIP.SYS 1460 2920 20
Change the value 1460 to 1024, and change the value 2920 to 2048.
Managing Channels and TCP Connections
In certain conditions, the supply of TCP connections can be totally exhausted. When you issue a COMMREQ to
establish a read or write channel, a TCP connection is created, the transfer(s) are made, then upon completion of all the