Most InTouch calls from a running plant start the same way: a screen shows stale values, an alarm summary stays empty, or a report comes out blank. AVEVA's InTouch HMI documentation has the tools to find out where the chain breaks, but they are spread over many pages. This article collects them in the order we check a running system: the tag, the Access Name, SuiteLink, the I/O server, then WindowViewer memory, HistData exports and licensing. It is based on AVEVA's InTouch HMI 2023 R2 SP1 P04 documentation. For upgrading old InTouch versions, see Upgrading Wonderware InTouch to AVEVA InTouch HMI 2023 R2.
1. Is the value on the screen good?
Every I/O tag carries quality information from the I/O server. The .QualityStatus dotfield returns 0 for Bad, 1 for Uncertain and 3 for Good, and AVEVA's example uses it in a script to log a message when the value is not Good. Showing the quality next to important values, or logging it, separates two different faults: a value that is wrong in the PLC, and a value that has stopped arriving.
2. Is the Access Name connected?
For each topic, InTouch provides a built-in discrete item called Status. It is 1 while communication with the I/O server is normal and 0 when communication fails. A tag defined with the item name Status on the same Access Name shows the state of the whole topic, and AVEVA notes that at least one I/O point on that topic must be active for the status to be meaningful. WindowViewer also has a built-in topic, IOStatus, to watch a single conversation; in versions before 7.0 it was called DDEStatus.
When the connection drops and does not come back, the Special menu in WindowViewer has Reinitialize I/O: Reinitialize All restarts every Access Name, and Select restarts only the chosen ones. With the Reinitialize Default option set in the WindowViewer configuration, the Access Name is restarted with its original node, application and topic, ignoring values changed at run time.
3. Is SuiteLink working?
AVEVA's SuiteLink checklist has three basic points: TCP/IP must work on the InTouch computer, the computer name must be 15 characters or fewer, and the SuiteLink service must be running. SuiteLink is installed with InTouch and starts automatically, but if the service stops it has to be started again.
From System Platform 2023, SuiteLink connections from a standard (non-administrator) user behave differently from earlier versions. AVEVA's table shows cases where a connection that only produced a warning in the Logger up to System Platform 2020 R2 SP1 now fails. The two Logger messages to look for are a WWSLS warning about a non-encrypted communication channel and a WWSLS error saying that encrypted inbound SuiteLink connections are not possible in this configuration. AVEVA's fixes include allowing unsecure connections in the Configurator, configuring secure SuiteLink with the System Management Server, and, where the System Management Server is configured, running WindowViewer as a service, with administrator rights, or with its user added to the ArchestrAWebHosting group.
4. Is the I/O server reading the PLC?
If the topic status stays at 0 while SuiteLink is running, the fault is usually in the I/O server or the path to the PLC. In our experience, the topic name in the Access Name must match the topic configured in the DAServer, OI Server or Gateway Communication Driver, and the driver's own diagnostics show whether it reaches the controller. Only after that is the network itself worth checking: a ping to the PLC, the cables and the switches.
5. WindowViewer closes windows or slows down
WindowViewer checks memory and the Windows GDI object count at regular intervals, by default every 5 minutes. When a limit is exceeded, it starts removing windows from memory. Opening a new window or popup also triggers a check. The interval is set with a MemoryHealthCheckInterval entry, in minutes, under the [Intouch] section of InTouch.ini in the application folder; a value of 0 turns the check off, and WindowViewer must be restarted for the change to apply. Switching between WindowViewer and WindowMaker clears the graphic and window caches.
6. HistData exports fail
AVEVA lists the common HistData messages and their causes. Some of the most frequent:
| Message or symptom | Cause given by AVEVA |
|---|---|
| Too much data requested | the SendData item asks for too much data; do not use SendData when the goal is only an output file |
| DATADIR item invalid | the folder in the DataDir item does not exist or is misspelled |
| STARTDATE item invalid | wrong date format in StartDate; AVEVA says to set the Windows date format to mm/dd/yy |
| No log files found | no log files for the requested date in the DataDir folder |
| Could not find tagname … in database | the tag is not in the Tagname Dictionary |
| Poke was rejected by the server (WriteFile) | a value assigned to a HistData item was invalid, or WriteFile was set to 0 |
| Only one record in the file | the Interval or Duration item has a wrong value or format |
7. WindowMaker or WindowViewer will not start
A valid licence is required before WindowMaker or WindowViewer can be used. The AVEVA License Server and License Manager are installed with InTouch, and in a workgroup (no domain) both must be on the same computer. For subscription licences, AVEVA's Flex model assigns users to entitlement seats through their AVEVA ID in the CONNECT portal.
What we note before changing anything
These are TDL's working habits, not AVEVA requirements:
- The time the fault started, matched against Logger messages on the InTouch computer and the I/O server.
- The quality and Status values at that time, so that a PLC fault and a communication fault are not confused.
- A backup of the application before any change, and the version and patch level of every node involved.
How TDL approaches it
TDL Industrial Automation is listed in AVEVA's Partner Finder as a System Integrator in the AVEVA Partner Ecosystem. We maintain InTouch and System Platform applications under yearly contracts, for example the facility and power monitoring systems at Samsung SEHC, and have reconfigured Wonderware applications after PLC upgrades at Nestlé Tri An. More on this service: AVEVA (Wonderware) system integrator in Vietnam.
Frequently asked questions
How do I know whether an InTouch value is still being updated?
Check the tag's .QualityStatus dotfield: 3 is Good, 1 is Uncertain and 0 is Bad. A tag with the item name Status on the same Access Name shows 1 while the topic communicates normally and 0 when communication fails.
What are the basic checks when SuiteLink does not connect?
AVEVA's checklist: TCP/IP working, a computer name of 15 characters or fewer, and the SuiteLink service running. From System Platform 2023, also check the Logger for WWSLS messages about encrypted or non-encrypted connections.
Why does WindowViewer close windows by itself?
WindowViewer checks memory and GDI usage every 5 minutes by default and removes windows when a limit is exceeded. The interval is set with MemoryHealthCheckInterval in InTouch.ini.
What does "STARTDATE item invalid" mean in HistData?
The StartDate item has a date format HistData cannot read; AVEVA's fix is to set the Windows date format to mm/dd/yy.
Sources
- AVEVA, Troubleshoot SuiteLink communication problems, InTouch HMI 2023 R2 SP1 P04 documentation
- AVEVA, Monitor I/O server communications status and Monitor the status of an I/O connection
- AVEVA, Reinitialize I/O connections with commands
- AVEVA, .QualityStatus dotfield
- AVEVA, Configure the memory health check interval and About managing memory for WindowViewer
- AVEVA, Troubleshoot HistData errors
- AVEVA, InTouch HMI licensing
Read 13 November 2026. This article paraphrases the sources and does not quote them; read the original documents before designing or working on a system.