Configuring Operator Prompts and Yes/No Decision Logic in SIMATIC BATCH and SFC Types

In SIMATIC PCS 7 and SIMATIC BATCH, native SFC Types do not possess dynamic pop-up windows with graphical 'Yes/No' buttons. Operator interactive decision prompts are engineered using SFC Type Characteristics: specifically Note Texts triggered via the internal step attribute OPTIPNO (Operator Prompt Number) for mandatory operator confirmations, and Position Texts triggered via POSINO for informational displays. To implement a functional Yes/No branching decision in an SFC Type or BatchCC recipe phase, engineers configure a Note Text instructing the operator to either acknowledge the prompt (Yes: transitions when OPTIPNO = 0) or select an explicit parameter/setpoint input on the faceplate (No: setting an enumerated parameter UserDecision = False), routing the sequencer through alternate transition branches.

Architecture of Operator Prompts in SFC Types and SIMATIC BATCH

Sequential Function Charts (SFC) automate discrete manufacturing sequences (e.g., vessel heating, agitating, draining). However, process safety and recipe validation frequently demand operator intervention: taking a physical laboratory sample, confirming manual valve alignment, or choosing whether to proceed following an equipment fault.

In SIMATIC PCS 7 SFC Types and SIMATIC BATCH, user interaction is governed by standardized attributes called Characteristics. Characteristics define the static text messages, setpoints, and status indicators exposed on the WinCC SFC faceplate and inside the Batch Control Center (BatchCC) runtime monitor.

Implementing Note Texts (`OPTIPNO`) and Position Texts (`POSINO`)

SFC Types provide two distinct text mechanisms:

Position Texts (POSINO): Informational status text. In a step action, assigning POSINO := 5 displays Position Text 5 on the faceplate. It informs the operator what the step is currently executing (e.g., 'Purging vessel with Nitrogen') without pausing sequence progression.
Note Texts (OPTIPNO): Mandatory operator prompt. In a step action, assigning OPTIPNO := 1 causes the SFC faceplate to display Note Text 1 accompanied by an active green prompt circle. The sequence halts in this step until the operator explicitly clicks the confirmation button ('O' / Acknowledge), which resets OPTIPNO to 0.

Engineering Yes/No Branching Logic and Transition Conditions

Because an SFC prompt provides only a single confirmation button ('OK'), implementing a binary 'Yes or No' decision requires combining a Note Text with an SFC parameter:

Define Note Text in SFC Type: 'Confirm: Press [OK] to execute auto-clean (YES), or set Parameter Bypass=TRUE to skip (NO)'.
Step Configuration: In the prompt step, set OPTIPNO := 1.
Transition Branch 1 (YES - Proceed):
- Condition: OPTIPNO = 0 AND Bypass = FALSE
- Next Step: Executes automated Clean-In-Place sequence.
Transition Branch 2 (NO - Skip):
- Condition: Bypass = TRUE
- Next Step: Skips cleaning and advances to next process phase.
- Step Action: Automatically resets OPTIPNO := 0 and Bypass := FALSE.

Operator Prompting and Control Strategy Selection in BatchCC

When an SFC Type is linked to a SIMATIC BATCH recipe unit phase, the prompt integration behaves consistently in BatchCC:

BatchCC Prompt Display: When OPTIPNO is asserted in the controller, BatchCC displays an active operator prompt in the Batch runtime window and highlights the batch control bar.
Batch Operator Dialog (BOD): Operators can confirm the prompt directly within BatchCC or via the WinCC SFC faceplate.
Control Strategy (CS) Selection: An operator can choose a Control Strategy (e.g., CS1: Fast Fill, CS2: Slow Dosing) when the phase is started manually. To allow interactive CS selection during automatic batch runs, configure an initial step that displays a prompt, allowing the operator to change the CS parameter on the faceplate before acknowledging.

Comparison of Operator Prompting Techniques in Sequential Control

The following table compares different methods for implementing operator intervention in PCS 7 sequential logic:

Prompting MechanismUser Input TypeRuntime Acknowledgment InterfaceBatchCC IntegrationBest Applied ScenarioNote Text (OPTIPNO)Single Button Confirmation (OK)Green Circle / 'O' Button on FaceplateNative BatchCC Prompt DialogSimple confirmations (e.g., 'Sample taken')Note Text + Parameter InputBinary Choice (Yes / No)OK Button + Faceplate Parameter CheckboxFaceplate + Batch Parameter DialogBranching decision logic (e.g., 'Retry or Abort')Position Text (POSINO)Informational Only (No Input)Static text line in faceplate headerInformational in Batch monitorProgress status trackingWinCC Message with DialogExternal Scripted DialogCustom modal popup windowNot synchronized with Batch engineNon-critical operator reminders

Verification

Verify operator prompting and branching logic in CFC / SFC:
1. Start the SFC sequencer in test mode (or start a test batch in BatchCC).
2. Allow the sequence to advance to the prompt step; verify that the step halts and that the Note Text message displays clearly on the faceplate.
3. Test 'YES' Pathway: Click the confirmation button ('O') without changing parameters; verify that OPTIPNO transitions to 0 and the sequencer follows Branch 1.
4. Reset sequence and reach prompt step again. Test 'NO' Pathway: Open the faceplate Parameters tab, set Bypass = TRUE; verify that the sequencer immediately follows Branch 2.
5. In BatchCC, confirm that the operator prompt is logged in the electronic batch record (EBR) with operator user ID and timestamp.

Limitations and Operational Precautions

Never configure an SFC prompt step without an automated timeout or safety fallback transition in unmanned or automated chemical processes; if an operator fails to acknowledge a prompt, heating or pressure buildup must not continue unchecked. In regulated pharmaceutical environments (FDA 21 CFR Part 11), operator prompt confirmations in SIMATIC BATCH require electronic signature authentication (username, password, and comment) configured via SIMATIC Logon.

Engineer FAQ

Can I create custom graphical 'Yes' and 'No' buttons on the SFC faceplate?

Not within the standard APL SFC faceplate templates. The standard faceplate enforces strict ISA-88 operating states. Custom buttons require modifying @pg_@sfc_type_standard.pdl with custom C-scripts, which is not recommended as it voids standard library updates.

What does the green circle on the SFC faceplate indicate?

The green circle indicates an active Operator Prompt (OPTIPNO > 0). It alerts the operator that the sequence is actively waiting for acknowledgment before it can advance.

How do I make BatchCC require an electronic signature for a prompt?

In BatchCC Permission Management, configure the action 'Acknowledge Operator Dialog' to require 'Signature with password' under SIMATIC Logon integration.

Technical References

Related Tags

SFC Types
SIMATIC BATCH
OPTIPNO
Operator Prompts
Control Strategy

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Configuring Operator Prompts and Yes/No Decision Logic in SIMATIC BATCH and SFC Types