INTERNSHIP DETAILS

PLC Application Development Intern 100% (m/f/d

CompanyEcolab
LocationWitterswil
Work ModeOn Site
PostedOctober 26, 2026
Internship Information
Core Responsibilities
The intern will develop and validate control software for Siemens S7-400 platforms used in continuous water treatment processes. Responsibilities include implementing sequence control, configuring alarms and diagnostics, and collaborating with the automation team on testing and documentation.
Internship Type
full time
Company Size
50476
Visa Sponsorship
No
Language
English
Working Hours
40 hours
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About The Company
A trusted partner for millions of customers, Ecolab (NYSE:ECL) is a global sustainability leader offering water, hygiene and infection prevention solutions and services that protect people and the resources vital to life. Building on more than a century of innovation, Ecolab has annual sales of $16 billion, employs approximately 48,000 associates and operates in more than 170 countries around the world. The company delivers comprehensive science-based solutions, data-driven insights and world-class service to advance food safety, maintain clean and safe environments, and optimize water and energy use. Ecolab’s innovative solutions improve operational efficiencies and sustainability for customers in the food, healthcare, high tech, life sciences, hospitality and industrial markets. For more Ecolab news and information, visit www.ecolab.com.
About the Role

Ultra-Pure Water+ division of Ecolab (former Ovivo Electronics), is a global provider of advanced equipment, technology, and systems to produce ultrapure water (UPW). We are dedicated to innovation, offering energy-efficient and environmentally sustainable solutions to the world’s most challenging water and wastewater issues.

As a PLC Application Development Intern, you will support our automation engineers in developing and validating a Siemens S7-400 control application for a continuous water treatment process.

Joining Ecolab means being part of a global team of innovative and passionate professionals who are committed to preserving water, our planet's most critical resource. It also means combining our efforts and talents towards a more sustainable future – together.


How You’ll Make an Impact:

· PLC application development: Develop control software for a Siemens S7-400 platform used in a continuous water treatment process.

· Sequence control: Implement process sequences using GRAFCET-based principles, operating modes, interlocks, and permissives.

· Alarm and diagnostics: Configure alarms, hardware diagnostics, and clear fault-handling logic for operators and maintenance teams.

· I/O and configuration: Integrate field I/O, equipment configuration, and process interfaces within the PLC application.

· Testing and simulation: Prepare and execute platform tests and simulations to validate real-time control behavior before deployment.

· Documentation and collaboration: Produce technical documentation and work closely with the local automation team during design reviews and testing.


Qualifications:

· You are completing a Bachelor's or Master's degree in automation, industrial computing, electrical engineering, computer science, robotics, or a related field.

· Knowledge of real-time PLC programming principles, sequential control or GRAFCET, and scripting is expected.

· Initial experience with Siemens SIMATIC Manager, TIA Portal, S7-300/400, or comparable PLC platforms is an advantage.

· You enjoy diversified tasks and hands-on work in technical workshops and on industrial systems.

· You show initiative and creativity, and you are flexible, structured, and able to work independently with guidance from experienced engineers.

· You have strong team-working and communication skills and can collaborate with international departments, suppliers, and customers.

· You have English skills suitable for daily business use. German, French, or other languages are an advantage.


What we offer:

· Working in our young and international Automation Team, with new challenges to solve every day.

· An opportunity to contribute widely and develop your skills in an agile company.

· Dealing with the cutting edge in ultrapure water technology in the electronic industry.

· Technical training in the position related field as well as the possibility for professional development in Switzerland.

· Expected start date: March 2027, or by mutual agreement.

· A modern workplace in Witterswil.

· At Ecolab we are committed to providing working environments where everyone is included and treated fairly and with respect


About Ecolab:

At Ecolab, we prioritize our talent-first philosophy by creating the most capable and diverse team to excel at our nearly three million customer sites. Building on a century of innovation, our 48,000 associates help deliver comprehensive science-based solutions, data-driven insights and world-class service to advance food safety, maintain clean and safe environments, and optimize water and energy use, and improve operational efficiencies and sustainability for customers in the food, healthcare, life sciences, hospitality and industrial markets in more than 170 countries around the world. Our solutions not only enhance operational efficiency but also contribute to sustainability and public health, making a positive impact on the world. We are committed to eliminating unnecessary complexities and embracing a beginner's mindset, continuously seeking new perspectives and innovative solutions to stay ahead in a rapidly changing world.


Ecolab’s commitment to diversity, equity and inclusion (DE&I) reflects our longstanding value of working together to integrate diverse perspectives to challenge ourselves, reach our goals and do what’s right.


Apply today and join one of the most ethical companies with over a hundred years of history.


Join Ecolab and help us protect what’s vital.

Key Skills
PLC programmingSiemens S7-400TIA PortalGRAFCETAutomation engineeringControl software developmentAlarm configurationFault-handling logicI/O configurationTechnical documentationSimulationIndustrial systemsElectrical engineeringRoboticsScripting
Categories
EngineeringTechnologyManufacturingEnvironmental & SustainabilityEnergy
Benefits
Technical trainingProfessional developmentInternational team environment