Industrial Automation Project Execution: The Ultimate 10-Step Field Checklist⏱ 1 دقیقه

Reading Time: 10 minutes

Author: Electrical Engineering Mohamad Zamani — Industrial Automation Design & Commissioning Engineer

Introduction⏱ 1 دقیقه

If there is one lesson I have learned over years of fieldwork in industrial automation projects, it is this: project success is determined long before you set foot in the plant — it is decided during the preparation phase. I have seen seasoned engineers stranded for hours, sometimes days, on an industrial site simply because they forgot a communication module or miscalculated a power budget. Lost time on the factory floor directly translates to production downtime and financial loss for the client.

In this article, I present a professional 10-step checklist for PLC-based project execution — one I have personally relied on across projects in steel, petrochemical, and cement industries.

1. Field Instrumentation Audit — Actuators & Sensors⏱ 1 دقیقه

The first step is a complete inventory of all I/O signals. You must know exactly:

  1. How many discrete/digital sensors? (Limit switches, reed switches, proximity sensors, encoders)
  2. How many analog sensors? (RTDs/PT100, thermocouples, 4–20 mA transmitters, load cells)
  3. What type of output actuators? Pneumatic valves (DO), VFDs (AO / fieldbus), contactors?

Golden Rule: Always reserve 15–20% spare I/O capacity for future expansion. This foresight has allowed many of my projects to go through expansion phases without hardware replacement.

2. I/O Module Sizing & Selection⏱ 1 دقیقه

Once signals are counted, it is time to select I/O modules:

  1. DI Module: For discrete sensors (typically 8, 16, or 32-channel)
  2. DO Module: For actuator commands — relay output for low-frequency switching, transistor for high-frequency
  3. AI Module: For analog signals with appropriate resolution (12, 13, or 16-bit)
  4. AO Module: For continuous control loops (control valves, VFD speed reference)

Field Experience: In harsh industrial environments (dust, high temperature, vibration), always specify isolated modules. The higher upfront cost is recovered through dramatically reduced failure rates over the asset lifecycle.

3. CPU/Processor Selection⏱ 1 دقیقه

The CPU is the heart of the system.

4. Specialty Module Specification — FM, CP & IM⏱ 1 دقیقه

**Work Memory**Sized to program volume (OB, FB, FC, DB count and size)**Processing Speed**Bit/word execution time; faster CPUs (e.g., S7-1500, CompactLogix 5580) for motion control and high-speed PID loops**Communication Ports**PROFINET, EtherNet/IP, PROFIBUS, Modbus TCP — match the existing industrial network architecture

This covers modules beyond basic I/O:

  1. FM (Function Module): High-speed counter (HSC), positioning/motion control, standalone PID controller
  2. CP (Communication Processor): Gateway to MES/ERP layer, serial (RS-232/485, MODBUS RTU), or dedicated industrial protocols
  3. IM (Interface Module): Remote I/O rack expansion for projects with high module counts

5. Power Budget Calculation & PSU Sizing⏱ 1 دقیقه

Calculating total power consumption is one of the most critical — yet most overlooked — steps:

  1. Extract current draw for every module from datasheets
  2. Account for inrush current at power-up
  3. Apply a safety factor of 1.25× to 1.5×
  4. Use an industrial UPS for critical loads (CPU, safety I/O modules)

Warning: An undersized or unstable power supply is the #1 cause of intermittent faults and erratic PLC behavior — and debugging it is a nightmare!

6. Hardware Configuration & Topology Setup⏱ 1 دقیقه

Inside the engineering framework (TIA Portal, Studio 5000, EcoStruxure Control Expert):

  1. Create a new project and select the correct CPU part number
  2. Configure all modules exactly matching the physical rack layout and slot assignment
  3. Verify and reassign I/O addressing (byte/word/DWord) as needed
  4. Document all network settings: IP Address, Subnet Mask, Default Gateway

7. Software Architecture & Block-Based Programming⏱ 1 دقیقه

A well-structured program is modular and readable. Recommended architecture:

  1. OB1: Main cyclic scan, calling sub-blocks
  2. FBs (Function Blocks): Reusable blocks for repetitive plant objects (motor, valve, PID loop) — each with its own Instance DB
  3. FCs (Functions): Stateless logic, calculations, and parameter-assignable subroutines
  4. DBs (Data Blocks): Global storage for setpoints, parameters, and recipe data

IEC 61131-3 Languages: LAD, FBD, SCL, STL, or Graph — choose the right language for the task. Each block should have a single, well-defined responsibility. This principle makes testing and troubleshooting dramatically easier.

8. PG/PC-to-PLC Communication & Download⏱ 1 دقیقه

Before heading to the site, test communication in the workshop:

  1. Industrial Ethernet cable (CAT6), USB-to-Serial adapter, or the required communication processor
  2. PG/PC Interface settings in your OS control panel
  3. Temporarily disable the firewall — this alone is the #1 source of connectivity headaches!
  4. Perform a complete download (HW Configuration + Software) and verify the CPU transitions to RUN mode

9. Commissioning & I/O Checkout⏱ 1 دقیقه

On-site, proceed step by step:

  1. Download the program with the CPU in STOP mode first
  2. One by one, test every input signal by physically actuating the field device (use Watch Table / Force Table)
  3. Test each output individually using Force (with strict safety lockout procedures)
  4. Only when all I/O points are verified, switch the CPU to RUN
  5. Always keep a golden backup image on external memory (MMC/SD card)

10. Software Tuning & Post-Commissioning Refinement⏱ 1 دقیقه

After the initial startup, the monitoring and refinement phase begins:

  1. Observe system behavior under real process conditions
  2. Investigate any unexpected scan cycle time spikes — check OB1 watchdog
  3. Fine-tune alarms and deadbands based on operator feedback
  4. Complete as-built documentation: circuit diagrams, I/O list, P&ID markups, and source code comments — all fully updated

Summary: The Formula for Automation Project Success⏱ 1 دقیقه

**Before Site**Execute this checklist line by line — 80% of success lives here**During Execution**Step-by-step testing, documentation, composure — do not panic**Post-Startup**Operator training, deliver documentation, final backup

These 10 steps are the distillation of years of field experience across Iran's heavy industries. Follow this checklist diligently, and I guarantee your project will reach completion with minimal headaches and maximum quality.

Questions or field stories to share? I'd love to hear them in the comments. If you would like a downloadable PDF version of this checklist, let me know and I will prepare one for you.

*© 2026 — All rights reserved.*⏱ 1 دقیقه