Publish a step number, blocking condition and cycle time from each PLC, map the values to text with a text list or dynamic dialog, and repeat the block once per machine on an overview screen. Archive step transitions in Tag Logging so a supervisor can analyse where cycle time was lost during a shift.
- One reusable faceplate per machine keeps a ten-machine overview maintainable; ten hand-drawn blocks do not.
- The blocking condition is what turns an overview screen from decoration into a fault-finding tool.
- Archiving step number lets you prove which step is costing cycle time instead of arguing about it.
Designing the Overview Screen
The sequence overview sits one level below the plant overview in the screen hierarchy. Its job is to show, for every machine on the line, what step is running and whether it is progressing.
Give each machine an identical block containing:
- Machine name and a status lamp driven by the status integer.
- Active step as readable text.
- Blocking condition text, visible only when a transition is held.
- Current step time and last cycle time.
- Mode indicator showing auto, manual or maintenance.
Build the block once as a faceplate or a library object with tag prefixes, then place instances for each machine. On a ten-machine line this is the difference between one object to modify and ten. Screen structure and hierarchy are covered in SCADA system architecture.
Keep the arrangement geographic where possible, matching the physical order of machines on the line. Operators navigate by where things are, not by alphabetical order.
Mapping Step Numbers to Text in WinCC
WinCC Explorer offers two practical ways to turn a step integer into text.
Text list
Create a text list in the Text Library and link it to a static text or an I/O field configured as a list. Each value maps to a string, and the text is translated with the rest of the project languages.
Dynamic dialog on the output value
Use a dynamic dialog with the step tag as the expression and one row per value, returning the text to display. This is quick for a small number of steps and keeps everything on the object.
| Step value | Displayed text | Expected duration |
|---|---|---|
| 0 | Idle, waiting for start | Not applicable |
| 10 | Homing | 8 s |
| 20 | Loading | 12 s |
| 30 | Processing | 45 s |
| 40 | Unloading | 10 s |
| 99 | Aborted, reset required | Not applicable |
Record the expected duration for each step in the same table and store it in the PLC. It gives you a step-time-exceeded warning without extra engineering, and it becomes the baseline for the archive analysis later in this lesson.
Showing Cycle Status and Blocking Conditions
The single most valuable element on the screen is the line that names what a stalled machine is waiting for. The PLC writes an identifier when a transition condition is not satisfied, and WinCC maps it to text exactly as it does the step number.
Make the text object visible only when the value is not zero, using a dynamic dialog on the Visibility property. During normal running the line is absent, so its appearance is itself a signal that something is being held.
Colour coding cycle status
| Condition | Screen behaviour |
|---|---|
| Step running within expected time | Normal text, no highlight |
| Step time exceeded | Amber highlight on the step time field |
| Transition blocked | Blocking condition text appears below the step |
| Machine faulted | Red status lamp and the first-out fault text |
| Machine in manual | Mode indicator changes and the step display is dimmed |
Pair the screen with the alarm system so a step time exceeded also produces an archived message; see TIA Portal to WinCC alarm configuration.
Build a plant overview in class
WinCC Explorer sessions cover faceplates, tag prefixes, archives and line-level overview screens.
Archiving Step Transitions for Analysis
A live screen answers what is happening now. Tag Logging answers what happened last night.
Archive the step number as a process value archive with acquisition on change. Every transition is stored with a timestamp, so the time spent in each step can be calculated afterwards.
- Create a process value archive in Tag Logging and add the step number tag with acquisition on change.
- Add the cycle time tag with cyclic acquisition at the end of each cycle.
- Set the archive size and backup path so data survives beyond the retention window.
- Display the archive in a table control on a history screen, filtered by machine and shift.
- Export to CSV or into SQL Server for longer-term analysis.
The analysis usually finds one step consuming far more time than its expected duration. That is a concrete engineering target rather than a general complaint about line speed.
Archive configuration and retention are covered further in SCADA trend configuration, and the panel-level version of this screen is in HMI sequence status screen.
Hands-On Lab: Build a Two-Machine Sequence Overview
Hands-on- WinCC Explorer with a connected PLC or a simulated tag set
- Step number, blocking condition, step time and cycle time tags for two machines
- Simulation only
- Estimated time: 45 minutes
Create the machine block
Build one machine block with status lamp, step text, blocking condition, step time and cycle time.
Make it reusable
Convert the block into a faceplate or library object using tag prefixes, then place a second instance for machine two.
Map the step text
Add the step values to a text list or dynamic dialog and link the step display.
Add the blocking condition
Map the blocking condition values to text and set a visibility dynamic for values above zero.
Archive the step number
Create a process value archive with acquisition on change for both step tags and display it in a table control.
One reusable object serves both machines, every stalled machine names its blocking condition, and the archive contains timestamped step transitions ready for analysis.
Frequently asked questions
Should I build one screen per machine or a single overview?
Build both. A line overview shows every machine at a glance, and a detail screen per machine gives the depth an operator needs when one of them stops.
Text list or dynamic dialog for step text?
A text list is better for many steps and multilingual projects because the strings live in the Text Library. A dynamic dialog is quicker for a small fixed set of values.
How do I archive step transitions without filling the archive?
Use acquisition on change rather than a cyclic acquisition. A record is written only when the step number actually changes, which keeps the archive small and precise.
What is the fastest way to find a slow step?
Archive the step number on change, calculate the time between transitions and compare it against the expected duration stored in the PLC for each step.