Siemens SINUMERIK Commissioning Manual page 173

(3) Blocking, very slow system
Problem:
The system is very slow and blocks the area switcher completely in some aspects. After a
certain period of time, all the operating actions are suddenly processed sequentially.
Possible causes:
The area application that is newly selected by the area switcher sets up hotlinks when
loading. When loading a form with DCTL, the message DDEInitialize is sent to the main
window of all processes. If a main window is very slow to answer or does not answer this
notification, then this can be the cause of the slow or blocked area switcher.
Rule:
"Top-level" windows must not be allowed to block the system for a long period of time.
DDE Clients may not use the DDEML. They must use the DCTL.
HMI Analyzer:
Select the DDE/Ping Windows item. Now you can check whether all windows answer the
DDE broadcasts while the cyclic operation is being started. The "Answer Time" should be set
to 100 ms and the cycle time of the query "Cyclic Time" to 1000 ms. The checkmark for
Append should be set and the checkmark for ShowAll should be removed. The applications
that appear in the list have not answered within the answer time. The displayed applications
can be the reason for the slow, blocking system.
Note
Clients that establish DDE connections during operation are particularly affected. Clients that
still use the DDEML should change to DCTL or limit the establishing of connections to the
application start. The problem is only solved after the 32 Bit DCTL. VB4.0 programs must be
ported accordingly.
For systems without much memory, the problem occurs more often. All of the processes
exported to the hard disk must be loaded into the main memory (e.g. DDE initialize) and
executed. This is very time-sensitive. Examples for time-critical applications are database
accesses, complex computation programs, etc. Background processes, in particular, must
be programmed in such a way that the applications that are running in the foreground are not
blocked.
(4) Slow communication times
Problem:
If too many hotlinks are set up, the communication times are significantly slowed down.
Possible causes:
Depending on the load on the PLC, the number of hotlinks that are causing problems differs.
Hotlinks represent a basic load for the control and as few as possible should be used.
HMI Advanced (IM4)
Commissioning Manual, 03/2009, 6FC5397-0DP10-3BA0
Diagnostics and service
5.7 HMI Analyzer
167