WinCC HMI Visibility Control for 8-Bit Binary 0000 0000

Overview: Why Multi-Bit Visibility Is Not Native in WinCC Comfort/Advanced

WinCC Comfort and WinCC Advanced — the engineering systems that back the TP 1500 Comfort, TP 700/900 Comfort, TP 1200 Comfort, and the WinCC Runtime Advanced on a PC — expose exactly two configurable triggers for the Visibility, Appearance, and Movement animations of a screen object: Single bit and Range. There is no third trigger that lets you specify a compound condition such as “visible when bit 0 AND bit 1 are both 1” or “visible when the 8-bit alarm code equals 0000 0000” using the configuration dialog alone. Any visibility rule that depends on more than one bit — or on a numeric value that is not a single equality match — must be reduced upstream. The two valid reduction paths are: (a) compute a derived boolean tag in the PLC and connect the HMI animation to that tag, or (b) override the visibility property at runtime with a VBScript scheduled task or value-change event.

This technical reference covers both reduction paths and shows the exact configuration steps, SCL code, ladder/FBD equivalents, and VBScript snippets for the common 8-bit alarm/status case (visibility on exact 0000 0000) and the more demanding 16-bit case (visibility on xxxx xxxx 0000 0000 — low byte = 0, high byte non-zero). All examples target TIA Portal V15 onward, the TP 1500 Comfort panel, and S7-1200/S7-1500 controllers, and are forward-compatible with TIA Portal V17, V18, V19, and V20.

Animation Trigger Types Available in WinCC Comfort/Advanced

When you right-click a screen object in the TIA Portal HMI editor and open Properties > Animations, the visibility, appearance, and movement animations each accept one and only one of two tag triggers. The choice is made in the “Configuration” column of the Animations table for the selected object.

The critical constraint — and the source of most visibility tickets — is that the dialog cannot be configured to evaluate multiple bits of a single tag, combine several bits with AND/OR/NOT, or evaluate bit patterns that require masking. The animation system reduces the selected trigger to a single boolean expression, and that expression is hard-limited to “tag = value” (Range) or “tag.bitX = TRUE” (Single bit). Any compound logic is the responsibility of the PLC CPU or of a VBScript running in the HMI runtime.

Solution 1: Range Animation for an Exact Binary Match

For the simplest case — make an object visible when an 8-bit tag is exactly 0000 0000 — the Range animation is sufficient because 0000 0000 binary equals decimal 0. No masking, no PLC code, and no script is required. This is the fastest configuration path and is recommended whenever the visibility condition is a single-value equality match.

1. In the TIA Portal project tree, open the HMI device (e.g., HMI_1 [TP1500 Comfort]) and double-click the screen that contains the target object.
2. Right-click the screen object (rectangle, symbol, text field, etc.) and choose Properties.
3. In the Properties inspector, switch to the Animations tab and click Add > Visibility.
4. In the new animation row, change the trigger type from “No trigger” to Range.
5. Click the tag selection field and pick the 8-bit tag (e.g., "AlarmByte" of data type BYTE, USINT, or SINT). The animation accepts any 1-byte numeric tag.
6. Set the range to 0 - 0 (low value = 0, high value = 0). This fires only when the tag equals 0.
7. Set the visibility behavior: map “In range” to Show and “Out of range” to Hide.
8. Compile the HMI (right-click HMI device > Compile > Software) and download to the panel.

Verification: In the HMI simulation (Start > Simulation > WinCC Runtime Advanced) or on the live panel, set the tag to 0 in the watch table or via the value-force toolbar. The object appears. Force the tag to any non-zero value (1, 2, 128, 255) — the object disappears. The animation is one-cycle deterministic; there is no debounce or hysteresis.

Solution 2: Deriving a Visibility BOOL in the PLC (Recommended)

For compound conditions — including the 16-bit pattern xxxx xxxx 0000 0000 where the low byte is zero but the high byte is non-zero — derive a dedicated boolean tag in the PLC and connect the WinCC visibility animation to that tag using the Single bit trigger. This is the most reliable, scan-deterministic, and firmware-portable approach. It is also the pattern Siemens documentation recommends for any visibility rule that depends on more than one bit of a single tag, because the rule is then executed on the controller (which has the data, the cycle time budget, and the bitwise instruction set) rather than on the panel (which has neither the full tag context nor a free-form logic engine in the engineering dialog).

The pattern requires three steps:

1. Define a new boolean tag in the PLC tag table, e.g., "Vis_AlarmLowByteZero" of type BOOL.
2. In a cyclic OB (OB1 for free-running, OB35 for time-sliced), evaluate the source tag and write the result to the boolean tag using bitwise AND, equality, and a second comparison to enforce the non-zero high-byte requirement.
3. On the HMI side, add the boolean tag to the HMI tag list, point the screen object’s visibility animation at it using the Single bit trigger (bit 0), and bind “In range” to Show.

The advantages over Range-only or script-only approaches: (a) the rule is auditable in the PLC watch table; (b) the rule does not consume HMI cycle time or VBScript scheduling slots; (c) the rule is identical across panels, PC runtime, and webUX; (d) the rule survives TIA Portal version upgrades because it is plain SCL.

SCL Bit-Masking Implementation

The PLC program snippet below runs in a cyclic OB (typically OB1) and produces a visibility flag for the 16-bit status word from the example. The code uses intermediate tags so the result is auditable in the watch table at every step.

// SCL — TIA Portal V15 onward, S7-1200/S7-1500
// Source: 16-bit WORD "StatusWord" (e.g., %MW100 or symbolic tag)
// Output: BOOL  "Vis_LowByteZero_HighByteNonZero"

// Step 1: Mask the low byte (bits 0..7)
"LowByte" := "StatusWord" AND 16#00FF;

// Step 2: Equality test — TRUE when the low byte is zero
"IsLowByteZero" := ("LowByte" = 0);

// Step 3: Inequality test — TRUE when the whole word is non-zero
//         (When the low byte is 0, this is equivalent to "high byte != 0")
"IsWordNonZero" := ("StatusWord" <> 0);

// Step 4: Combine
"Vis_LowByteZero_HighByteNonZero" := "IsLowByteZero" AND "IsWordNonZero";

Notes on the bit-mask syntax: TIA Portal SCL accepts the prefix 16# for hexadecimal literals and the underscore _ as a digit-group separator (e.g., 16#00FF is equivalent to 16#00ff and to 255). The mask 16#00FF zeros the high byte while preserving the low byte; the AND operation is performed bitwise on a 16-bit WORD. The TIA Portal Test Suite documentation on binary numbers confirms the value range of a 16-bit WORD is 16#0000_0000 to 16#FFFF_FFFF (when interpreted as a 32-bit pattern) or 0 to 65535 unsigned — both interpretations yield the same mask result here.

Compact equivalent (single line, no intermediates):

"Vis_LowByteZero_HighByteNonZero" :=
    (("StatusWord" AND 16#00FF) = 0) AND ("StatusWord" <> 0);

Place the snippet in OB1 immediately after the code that updates "StatusWord", or in a dedicated FC (function) that is called once per cycle. Both placement options are equivalent for cycle determinism; the FC approach is preferred when the rule is reused across multiple status words.

Ladder and FBD Equivalents for S7-1200 and S7-1500

If the project is maintained in LAD (ladder) or FBD (function block diagram) rather than SCL, the bit-mask and equality combination is built from two CALCULATE boxes (or one CALCULATE plus one comparator) plus an AND gate. The CALCULATE box is in the “Bit logic” operations folder under “Math functions” in the TIA Portal instruction catalog.

Network 1 — mask and compare to zero:

1. Insert a CALCULATE box (CALCULATE_1) on rung 1. Set OUT to "LowByte" (WORD).
2. Define one input pin: IN1 = "StatusWord" (WORD).
3. In the expression field, enter: IN1 AND 16#00FF
4. Insert an EQ_W comparator on rung 2. Inputs: IN1 = "LowByte", IN2 = 0. Output: "IsLowByteZero".

Network 2 — combine:

1. Insert an AND logic box. Inputs: "IsLowByteZero" and "IsWordNonZero". Output: "Vis_LowByteZero_HighByteNonZero".
2. Insert an NE_W comparator to compute "IsWordNonZero": IN1 = "StatusWord", IN2 = 0, output = "IsWordNonZero".

Ladder is slightly more verbose than SCL but offers better online monitoring because each rung state is visible in the LAD editor with green power-rail indicators. For an S7-1500 with active trace recording, the trace can capture "StatusWord" and the derived boolean in the same trace window to confirm timing.

VBScript Runtime Override for TP 1500 Comfort

TP 1500 Comfort (and all Comfort panels from TP 700 onward) ship with a VBScript runtime. If a derived boolean in the PLC is not acceptable — for example, when the panel must react to a tag that is not on the same controller, or when a quick change is needed in commissioning without re-downloading the PLC — write a VBScript procedure and bind it to a value-change event on the source tag.

Open the HMI project, expand Scripts in the project tree, right-click VB Scripts, and choose Add new VB function. Name it Update_Vis_LowByteZero and paste the following code:

' VBScript — TIA Portal WinCC Comfort/Advanced
' Triggered on value change of the source tag
Function Update_Vis_LowByteZero()
    Dim srcWord
    Dim lowByte
    Dim visible

    srcWord = SmartTags("StatusWord")
    lowByte = srcWord And &H00FF       ' Bitwise AND with 0x00FF
    If (lowByte = 0) And (srcWord <> 0) Then
        visible = True
    Else
        visible = False
    End If
    SmartTags("Vis_LowByteZero_HighByteNonZero") = visible
End Function

Bind the function to the value-change event of StatusWord: in the HMI tag editor, open the tag properties, switch to the Events tab, and on the Value change row choose Update_Vis_LowByteZero as the function. The script runs synchronously on the panel’s main thread and writes the boolean tag, which the visibility animation then evaluates as a Single bit trigger.

Limitations of the script approach: VBScript on Comfort panels runs single-threaded with the rest of the runtime; heavy scripts starve the tag polling cycle. The function above executes in well under 1 ms on a TP 1500 Comfort and is safe. If the rule grows (e.g., eight status words, each with its own derived boolean), consolidate the logic into a single function and trigger it from a 100 ms scheduled task rather than from value-change events on every tag.

Tag Data Types and HMI Pointing

The PLC tag "StatusWord" in the examples above can be declared as WORD (unsigned 16-bit) or INT (signed 16-bit). Both yield the same bitwise mask result because the AND is performed on the bit pattern, not on the numeric interpretation. The HMI tag that points to the PLC tag must be of the matching type — declare the HMI tag as WORD for best clarity, since INT implies signed semantics in the HMI faceplate display.

The TIA Portal Test Suite binary numbers reference documents the same ranges for the test framework. Use BYTE or WORD for alarm/status codes to keep the human-readable representation aligned with the bit pattern; INT or DINT introduce sign-extension noise that can confuse the operator when the HMI displays the value.

Pointing the HMI tag: in the HMI tag table (project tree > HMI device > HMI tags), add a tag of type WORD named StatusWord and set the connection to the PLC; TIA Portal auto-fills the address from the symbolic PLC tag if the project is integrated. For separated HMI and PLC projects, manually enter the absolute address (e.g., %DB5.DBW0) and the acquisition cycle (default 1 s is fine for visibility; lower to 100 ms if the visibility must react to fast-changing alarms).

TP 1500 Comfort and Firmware Constraints

The TP 1500 Comfort (Siemens catalog 6AV2 124-1QC02-0AX0 and successors) is a 15.4-inch widescreen TFT panel with a PROFINET interface, 16 million colors, and WinCC Comfort V15+ as its image. The visibility animation system, the Single bit and Range triggers, and the VBScript runtime have been present in the Comfort image since V13 SP1 and are unchanged in V14, V15, V15.1, V16, V17, V18, V19, and V20. There is no firmware-version-specific limit that would block either of the solutions in this article.

What does change between panel firmware versions is the supported TIA Portal engineering baseline:

For most visibility work the choice of panel firmware does not matter. The constraint that does matter is on the controller side: TIA Portal V20 supports S7-1200 firmware V4.0 through V4.6 and S7-1500 firmware V1.8 through V3.1. If the S7-1200 is on firmware V3.x, you must build the project in TIA Portal V16 or earlier, which is also fine for the SCL snippet in this article because the syntax is unchanged. The PLC firmware compatibility is a project-planning concern, not a visibility-animation concern.

TIA Portal V15 to V20 Compatibility Notes

The Range and Single bit animation triggers, the bitwise AND / equality / AND combination in SCL, and the VBScript SmartTags object are stable across TIA Portal V13 SP1 through V20. The article’s examples compile and run identically on V15 (the version cited in the original project) and on V20 (the current shipping version). Differences that do exist are:

• V16 onward: the project can contain a Unified Comfort panel alongside the TP 1500 Comfort. The Unified panel uses a different visibility scripting model (JavaScript and property binding), not the Single bit / Range triggers of the Comfort line. Do not copy animations from a TP 1500 Comfort into a Unified panel without rewriting them.
• V17 onward: the SCL editor gains additional warnings for implicit type conversions. The snippet in this article compiles clean because the literals are explicitly typed (16#00FF is a hex WORD literal; 0 is an INT literal that the compiler widens).
• V18 / V19 / V20: the project view adds a “Documentation” tab that auto-generates HTML documentation for each function, including the derived-visibility FC. This is useful for the project quality manual but does not change the code.

There is no TIA Portal version in which a Single bit + Range combination of multiple bits became possible in the configuration dialog. The dialog has been engineered around the two-trigger model since the Comfort line replaced the Multi Panel line in 2011, and the same constraint exists in V20 today.

Verification and Commissioning Procedure

1. Force in the watch table. Open the PLC watch table, add StatusWord, LowByte, IsLowByteZero, IsWordNonZero, and Vis_LowByteZero_HighByteNonZero. Force StatusWord to 16#0100 (256). Confirm Vis_LowByteZero_HighByteNonZero is TRUE.
2. Negative test. Force StatusWord to 16#00FF (255). Confirm Vis_LowByteZero_HighByteNonZero is FALSE. Force to 16#0000 (0). Confirm FALSE (high byte also zero).
3. Boundary test. Force StatusWord to 16#FF00 (65280). Confirm TRUE. Force to 16#0101 (257). Confirm FALSE (low byte non-zero).
4. Live PLC test. Place the SCL snippet in OB1, compile, and download. Set the actual alarm source to write the test values into StatusWord. Verify the boolean tag follows.
5. HMI simulation. In TIA Portal, right-click the HMI device and start the simulation (WinCC RT Advanced starts in a window). Connect the simulation to PLCSIM (or a real controller). Observe the screen object: visible when 16#0100 is forced, hidden when 16#00FF is forced.
6. On-panel test. Download the HMI project to the TP 1500 Comfort. From a second engineering station or a webUX client, force the boolean tag and confirm the panel updates within one acquisition cycle (default 1 s).
7. Performance check. Open the HMI performance trace (Tools > Performance). Confirm the value-change event fires within 50 ms of the tag change and the visibility animation evaluates within one screen refresh.

Troubleshooting Matrix

FAQ