Selmo PTF

The deterministic standard for process definition and function development

1. Introduction

Selmo PTF stands for Structured Execution Logic for Machine Operation – a method that completely describes machine behavior, documents it formally and deterministically translates it into control code.

For Selmo to unfold its full effect, the development process must be defined as precisely as electrical or mechanical designs. The Selmo PTF process provides the binding framework for this: It describes, what is developed (process), with what it is realized (technology) and how how it works (function).

PTF stands for:

• P – Process: Description of the physical and logical sequence

• T – Technology: Description of the technologies, components and interfaces used

• F – Function: Description of the individual functions acting in the process

The PTF process is thus the Clarifies the process goal with the customer, provides reliable data for proposal & effort estimation of Selmo: It defines the requirements that are later formally verified in the model and code.

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2. Objective of the PTF process

The PTF process serves the clear, verifiable and complete description of a machine or plant, before it is modeled and programmed. Goals are:

• Complete traceability from requirements to behavior

• Unambiguous separation of process, technology and function

• Deterministic execution and formal verification of the code

• Reduction of complexity through standardization and reuse

• Automated documentation and verifiable functions

• Responsibilities and interfaces clearly defined

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3. The PTF approach at a glance

The PTF process is divided into three levels that are worked on sequentially and interconnected:

Level	Description	Result
Process	Definition of the work or production process – physical, logical, sequential.	Process description with states, conditions, parameters
Technology	Definition of the technologies, components, interfaces and sensing/actuation used.	Technology matrix with all relevant devices and connections
Function	Definition of the generic functions to be executed with inputs, outputs and boundary conditions.	Function library with documented, verifiable functions

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4. The PTF as a SIPOC process

According to the lean principle (Supplier – Input – Process – Output – Customer) the PTF process is clearly structured:

element	Description	Example
Supplier	Who supplies the input?	Process owner, designer, customer
Input	What information is required?	Process description, function requirements, technology overview
Process (PTF)	How are process, technology and function described and verified?	PTF documentation, modeling, review
Output	What is produced?	Complete PTF report (process, technology, function), ready for Selmo modeling
Customer	Who uses the result?	Software developers, commissioning, quality management

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5. Process flow in the PTF

The PTF process follows a clearly defined sequence with assigned tasks and responsibilities:

Step 1 – Process definition

• Description of the sequence: steps, states, logical transitions

• Definition of process-relevant parameters (inputs, times, tolerances)

• Clarification of boundary conditions and abort criteria

Result: Process description with structure diagram (SIPOC + state logic)

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Step 2 – Technology overview

• Definition of all sensors, actuators, control components used

• Definition of interfaces to subsystems (e.g. robots, MES, HMI)

• Check for determinism and Selmo compliance → Every technology must be testable, standardized and deterministically addressable.

Result: Technology matrix with signal list and interface description

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Step 3 – Function definition

• Description of all functions (e.g. adder, cylinder control, valve monitoring)

• Specification of inputs, outputs, limits, monitoring conditions

• Definition of trigger conditions (trigger, start, stop, feedback)

• Goal: Each function is fully documented, verifiable and reusable

Result: Function catalog with documented standard functions

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Step 4 – PTF review & approval

• Check for completeness and consistency

• Acceptance by project management / quality responsible

• Approval for modeling in Selmo Studio

Result: Approved PTF report as basis for modeling

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6. Responsibilities and interfaces

Role	Task	Deliverable
Process owner	Delivers process description, parameters, dependencies	Process document
Technology owner (electrical/mechanical)	Delivers sensors, actuators, interface overview	Technology matrix
Function owner / software engineer	Defines functions, limits, tests	Function catalog
Selmo modeler	Generates sequence and zone model from PTF	Process model in Selmo Studio
Quality / project management	Checks and releases the PTF	Release protocol

The Interface between PTF and modeling is unambiguous: → The PTF delivers all verified requirements, → the Selmo model implements them formally and deterministically into control code.

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7. Completion criteria of the PTF process

A PTF is considered complete when:

1. process description is complete and understandable

2. Technology list contains all components and interfaces

3. functions are defined, documented and verifiable

4. Responsibilities are clear

5. Review protocol is available

6. Approval for modeling has been granted

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8. Importance for project management

The PTF process ensures that every project:

• risk rating has a clear starting point with complete requirements,

• no interpretation gaps arise between disciplines (mechanical, electrical, software),

• the Documentation automatically remains consistent with the model,

• the Risk assessment is supported by formal traceability,

• and the result is deterministic and verifiable is.

Selmo thereby becomes the binding regulation for digital machine description – equivalent to electrical or mechanical design.

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9. Conclusion – Why Selmo PTF

The Selmo PTF is more than a documentation standard. It is the methodical basis, on which modern, safe and traceable automation is built.

It turns requirements into a verifiable system, technology into a clearly defined architecture, and functions into reusable building blocks that are executed deterministically – in every machine, every project, every plant.