Henderson Brown Software Engineer interview questions & guide 2026

The interview process is designed to evaluate both your theoretical understanding of industrial software architecture and your practical, hands-on troubleshooting capabilities. The following questions represent common patterns and topics that frequently arise during the technical and behavioral screening stages for these roles.

PLC & Control Logic Design

This category tests your ability to write clean, maintainable, and efficient control software for industrial machinery. Interviewers want to see how you structure your logic and handle real-time processing constraints.

• Explain how you structure a PLC program to ensure it is easily readable and maintainable by other engineers.
• How do you handle race conditions or asynchronous inputs in a high-speed packaging environment?

Preparing for an interview through Henderson Brown requires a balanced focus on software logic, electrical integration, and rapid problem-solving. To stand out, you must demonstrate that you can think like both a software developer and a systems engineer.

Technical Competence – You must show a deep understanding of PLC programming languages (such as Ladder Logic, Structured Text, and Function Block Diagrams) and industrial networking protocols. Be ready to explain the architectural decisions behind your code.

Analytical Troubleshooting – Interviewers are highly interested in your diagnostic methodology. You should be able to articulate a structured, logical approach to isolating variables, reading error codes, and implementing permanent software fixes rather than temporary workarounds.

Safety & Compliance – In industrial environments, software controls physical machinery that can be hazardous. Demonstrating a proactive safety-first mindset, understanding machinery safety directives, and knowing how to safely isolate systems are non-negotiable criteria.

Communication & Influence – You must be able to translate complex technical software issues into clear, actionable business insights for non-technical stakeholders, such as plant managers and production operators.

The interview process for engineering and software roles managed by Henderson Brown is thorough, structured, and designed to ensure a strong technical and cultural fit with the hiring client. Because Henderson Brown is a premier specialist recruitment agency, your journey begins with an expert consultant who understands the industrial automation market and helps tailor your presentation.

The process typically moves from initial alignment to deep technical validation, ending with an onsite evaluation where you can see the physical systems you will be managing. The pace is generally efficient, often concluding within two to four weeks depending on the urgency of the client's operational needs.

This visual timeline outlines the typical progression from your first contact to the final decision. You should use this roadmap to pace your preparation, focusing first on high-level communication and core technical concepts before diving into deep diagnostic scenarios and onsite preparation. While there may be slight variations depending on whether the role is a permanent Lead Engineer position or a Contract E&I Engineer assignment, the core stages of technical and behavioral vetting remain consistent.

To succeed in this interview process, you must excel across several distinct technical and operational domains. Below is a detailed breakdown of these core evaluation areas.

PLC Programming & SCADA Integration

This area evaluates your core software engineering skills applied to physical automation. Interviewers will test your mastery of standard industrial programming environments and your ability to manage data flow from the physical sensor up to enterprise-level SCADA systems.

Be ready to go over:

• IEC 61131-3 Standards – Deep familiarity with Ladder Diagram (LD), Structured Text (ST), and Function Block Diagram (FBD).
• SCADA & HMI Configuration – Designing clear user interfaces, managing alarm databases, and configuring real-time data logging.
• Industrial Networking – Configuring and troubleshooting Profibus, Profinet, EtherNet/IP, and Modbus networks.
• Advanced concepts (less common) – Integrating OPC UA servers, managing SQL database connections directly from PLCs, and implementing basic MQTT protocols for Industrial IoT (IIoT) applications.

Example questions or scenarios:

• "How would you write a Structured Text routine to calculate the running average of an analog temperature sensor while filtering out high-frequency noise?"
• "Describe how you would configure a SCADA system to archive historic alarm data without degrading real-time communication performance."

Fault Diagnosis & Systems Recovery

This evaluation area focuses on your ability to restore production rapidly and safely when automated systems fail. You must demonstrate a methodical, calm approach under high-pressure conditions.

Be ready to go over:

• Root Cause Analysis (RCA) – Utilizing techniques like the "5 Whys" to identify the underlying failure point of a system.
• Software Debugging Tools – Using online monitoring, force tables, and trend charts to trace logic execution in real time.
• Hardware-Software Interface – Verifying digital/analog I/O cards, checking loop drawings, and testing sensor calibration.

Example questions or scenarios:

• "An automated sorting system stops intermittently without throwing a clear software alarm. Walk me through your step-by-step diagnostic process."
• "How do you safely use PLC force functions during a breakdown, and what risks must you mitigate?"

Electrical & Instrumentation (E&I) Integration

Software in this domain does not exist in a vacuum; it directly controls electrical and physical hardware. You must prove your capability to read schematics and safely integrate software logic with physical electrical panels.

Be ready to go over:

• Control Panel Schematics – Reading and interpreting complex electrical drawings, wiring diagrams, and P&IDs (Piping and Instrumentation Diagrams).
• Variable Speed Drives (VSDs) & Motion Control – Programming and tuning servo drives, frequency inverters, and motor starters.
• Instrumentation Calibration – Configuring and scaling 4-20mA, 0-10V, and digital smart sensors.

Example questions or scenarios:

• "Explain how you would troubleshoot a closed-loop PID controller that is causing a control valve to oscillate wildly."
• "How do you set up and scale a new analog weight transmitter within your PLC control program?"

As a Software Engineer specializing in industrial automation and maintenance, your day-to-day responsibilities will bridge the gap between digital logic and physical production. You are responsible for ensuring the continuous, optimal performance of automated machinery across the facility.

On a typical day, you will write, modify, and debug PLC and HMI programs to accommodate new product lines, improve cycle times, or enhance safety protocols. You will spend a significant portion of your time on the plant floor, collaborating with mechanical and electrical technicians to diagnose complex system faults, optimize machine performance, and commission new capital equipment.

Additionally, you will lead preventative maintenance initiatives for the plant's software infrastructure. This includes managing software backups, updating system documentation, and implementing cybersecurity best practices for operational technology (OT) networks. For senior or lead positions, you will also mentor junior technicians and coordinate with external automation contractors during major facility shutdowns and system overviews.

The requirements for these roles reflect the highly specialized nature of industrial software and control systems. Candidates must possess a strong blend of software proficiency, electrical knowledge, and practical troubleshooting experience.

• Must-have skills – Strong proficiency in programming major PLC brands (such as Siemens TIA Portal, Rockwell Studio 5000, or Mitsubishi GX Works), experience designing HMI and SCADA interfaces, and the ability to read and interpret electrical schematics.
• Nice-to-have skills – Certification in electrical regulations (such as UK 18th Edition), experience with robotic systems (ABB, Fanuc, or Kuka), and familiarity with SQL databases or industrial scripting languages like Python.
• Experience level – Typically requires 3+ years of experience in an automated manufacturing, packaging, or heavy industrial environment for standard roles, and 6+ years with demonstrated project management experience for lead positions.
• Soft skills – Exceptional logical reasoning, strong communication skills under pressure, and a proactive, collaborative approach to teamwork.

Q: What is the primary focus of the Software Engineer roles at Henderson Brown? A: These roles focus on industrial software engineering, specifically controlling physical machinery, automated production lines, and robotic systems. The work involves programming PLCs, HMIs, and SCADA systems rather than traditional web or mobile application development.

Q: How technical are the interviews? A: The interviews are highly technical and practical. You should expect to talk through specific programming architectures, explain your fault-finding methodologies, and potentially interpret electrical schematics or write sample control logic during the process.

Q: What is the work environment like? A: The environment is dynamic and hands-on. While you will spend time designing software at a desk, you will also spend significant time on the production floor working directly with machinery, sensors, and electrical panels.

Q: Are there opportunities for contract work? A: Yes, Henderson Brown frequently recruits for both permanent positions (such as Maintenance and Lead Engineers) and specialized contract roles (such as Contract E&I Engineers) depending on client project demands.

To maximize your chances of success during the recruitment process, keep these practical tips in mind:

• Use the STAR Method: When answering behavioral and diagnostic questions, structure your answers using the Situation, Task, Action, and Result framework. Focus heavily on your specific technical actions and the measurable operational results (e.g., reduced downtime, increased throughput).

• Highlight Safety First: Always emphasize safety protocols, such as Lockout-Tagout (LOTO) and risk assessments, when explaining your troubleshooting or programming processes.

• Be Ready for Ambiguity: In industrial environments, problems are rarely straightforward. Demonstrate how you systematically narrow down variables when presented with vague or conflicting system symptoms.

Securing a Software Engineer role through Henderson Brown is an excellent opportunity to advance your career in the rapidly growing field of industrial automation and smart manufacturing. By combining your software logic expertise with practical, hands-on engineering skills, you will play a critical role in driving the efficiency of major industrial facilities across the country.

To prepare effectively, focus your energy on reviewing core PLC logic standards, practicing structured diagnostic scenarios, and refining how you communicate technical issues to broader business teams. Consistent, focused preparation will ensure you stand out as a highly competent, safety-conscious, and proactive engineer.

For more detailed interview insights, company-specific preparation tools, and real-world candidate experiences, be sure to explore the comprehensive resources available on Dataford.

The salary data reflects the competitive compensation packages available for these specialized engineering roles across various regions in England. These figures represent base salaries, which are frequently supplemented by shift allowances, overtime opportunities, and performance bonuses depending on the specific operational requirements of the hiring client. Use these benchmarks to align your compensation expectations based on your location and experience level.