PLC Platforms We Program
We develop control logic across the leading PLC platforms using industry-standard IEC 61131-3 programming languages.
Siemens TIA Portal
S7-1200, S7-1500, S7-300/400 legacy migration
Full TIA Portal programming for S7-1200 and S7-1500 controllers. Ladder, FBD, SCL, and Graph languages. WinCC HMI integration, Profinet configuration, and PLCSIM validation.
Rockwell Studio 5000
ControlLogix 5580, CompactLogix 5380, Micro800
Logix design environment for ControlLogix and CompactLogix controllers. Ladder, FBD, SFC, and structured text. FactoryTalk View integration and EtherNet/IP configuration.
Delta WPLSoft / ISPSoft
DVP-SS2, DVP-ES2, DVP-EC3, AS228P, AH500
Programming suites for Delta's DVP (WPLSoft) and AS/AH (ISPSoft) series. Ladder logic with motion control instructions, Modbus configuration, and CANopen networking.
Our PLC Programming Services
From logic design through simulation, commissioning, and IIoT connectivity — we cover the full PLC programming lifecycle.
PLC Logic Design & Development
Custom PLC program development in ladder logic, FBD, SCL, and structured text. We design robust, well-commented control code optimised for your specific machinery, process, and operational requirements.
HMI & SCADA Integration
Seamless integration between PLC logic and operator interfaces. WinCC, FactoryTalk View, Delta DOPSoft, and Ignition SCADA with real-time data, alarm management, trending, and operator controls.
Control Logic Simulation & Testing
Offline and hardware-in-the-loop simulation using TIA Portal PLCSIM, Studio 5000 Emulate, and Delta ISPSoft simulation. Full FAT (Factory Acceptance Testing) before site deployment.
Legacy PLC Migration & Upgrades
Migration of aging PLC systems: Siemens S5 to S7-1500, Allen-Bradley PLC-5/SLC-500 to ControlLogix/CompactLogix, Mitsubishi FX/A to iQ-R. Logic conversion, hardware replacement, and recommissioning.
Safety PLC Programming (SIL)
Fail-safe PLC programming for safety-critical applications using Siemens F-CPUs, Allen-Bradley GuardLogix, and safety-rated function blocks. SIL 2 and SIL 3 certified logic for emergency stop, light curtains, and guard monitoring.
Remote Monitoring & IIoT Connectivity
Add OPC UA, MQTT, and edge gateway connectivity to your PLC program. Enable production dashboards, remote PLC diagnostics, predictive alerts, and data logging without disrupting existing control logic.
IEC 61131-3 Programming Languages
We write PLC programs in all five IEC 61131-3 standard languages, selecting the best language for each control task.
Ladder Logic (LAD)
Graphical relay-logic style. Ideal for discrete control, interlocking, and safety circuits. Our primary language for machine control and conveyor sequencing.
Machine control, conveyors, safety circuitsFunction Block Diagram (FBD)
Signal-flow oriented graphical language. Excellent for process control loops, analog conditioning, and drive control applications.
Process control, PID loops, drive controlStructured Text (ST)
High-level textual language similar to Pascal. Used for complex math, data handling, array processing, and algorithm implementation.
Data processing, math, algorithmsSequential Function Chart (SFC)
Step-transition based language for sequential processes. Ideal for batch processing, recipe management, and state-machine logic.
Batch processing, recipe control, state machinesInstruction List (IL) / SCL
Siemens SCL is a high-level language for complex calculations. IL is a low-level mnemonic language for legacy system support.
Complex calculations, legacy supportContinuous Function Chart (CFC)
Free-form graphical language in TIA Portal for connecting function blocks without network limitations. Used for complex process strategies.
Complex process strategies, drivesPLC Programming Applications
Our PLC programs control machinery and processes across diverse South African industries.
Manufacturing Lines
Assembly, filling, labeling, and inspection line control with coordinated multi-PLC programs for high-speed production.
Water Treatment Plants
Pump sequencing, chemical dosing, filtration backwash, and SCADA-integrated PLC programs for municipal and industrial water systems.
Mining & Mineral Processing
Conveyor interlocking, crusher control, pump station automation, and ventilation fan sequencing for surface and underground mining.
Process & Batch Control
Recipe management, temperature profiling, mixing sequences, and batch tracking PLC programs for food, chemical, and pharmaceutical processing.
Material Handling
Conveyor sortation, warehouse logistics, palletiser control, and AS/RS crane automation with PLC-coordinated motion control.
Energy Management
Generator load sharing, power monitoring, load shedding automation, and solar integration PLC programs for industrial facilities.
Why Choose Cretek for PLC Programming in South Africa?
Cretek is a South African PLC programming company with certified expertise across Siemens TIA Portal, Rockwell Studio 5000, and Delta ISPSoft/WPLSoft platforms. Our PLC programmers develop robust, well-documented control logic for manufacturing, mining, water treatment, and process industries nationwide. Whether you need Siemens S7-1500 programming for a production line, Allen-Bradley CompactLogix programming for a conveyor system, or Delta DVP programming for a packaging machine, we deliver reliable, production-ready code.
We follow structured software development practices: requirements analysis, architecture design, modular coding with version control (Git), offline simulation in TIA Portal PLCSIM or Studio 5000 Emulate, Factory Acceptance Testing (FAT), on-site commissioning, and Site Acceptance Testing (SAT). Every control program is delivered with comprehensive documentation including I/O lists, variable tables, operational descriptions, and maintenance guides.
Our PLC programming services cover the full project lifecycle — from feasibility studies and control philosophy documentation through logic development, HMI/SCADA integration, panel testing, site commissioning, and ongoing support. We serve clients in Gauteng, Johannesburg, Pretoria, Boksburg, Midrand, and across South Africa with on-site engineering support and remote programming capabilities.
PLC Programming — Frequently Asked Questions
What is PLC programming and how does it work?▼
PLC programming involves writing control logic that tells a Programmable Logic Controller how to operate machinery. The programmer uses specialised software (like TIA Portal or Studio 5000) to create a program using Ladder Logic, Function Blocks, or Structured Text. The completed program is downloaded to the PLC via Ethernet or USB, and the PLC then executes the logic in a continuous scan cycle, reading inputs and controlling outputs in real time.
Which IEC 61131-3 language should I use for my project?▼
Each language has strengths. Ladder Logic (LAD) is best for discrete control and is familiar to most electricians. Function Block Diagram (FBD) excels in process control with analog signals. Structured Text (ST) handles complex math and data processing efficiently. Sequential Function Chart (SFC) is ideal for batch processes with distinct steps. Our engineers recommend the optimal language — or combination of languages — for your specific application.
Can you integrate PLC programming with existing SCADA or HMI systems?▼
Yes. We integrate PLC logic with Siemens WinCC, Rockwell FactoryTalk View, Delta DOPSoft HMI, and Ignition SCADA platforms. We handle tag mapping, alarm configuration, data logging, and historian setup. Our PLC programs include well-structured data blocks and global variables designed for seamless SCADA integration from the ground up.
Do you provide documentation and training for the PLC programs you write?▼
Absolutely. Every project includes full technical documentation: I/O schedules, variable/tag lists, program architecture overview, operational descriptions, alarm lists, and maintenance procedures. We also offer operator and maintenance team training sessions on-site or remotely to ensure your team can operate and troubleshoot the system confidently.
How do you ensure PLC program quality and reliability?▼
We follow a structured quality process: peer code reviews, offline simulation testing, FAT (Factory Acceptance Testing) with hardware-in-the-loop, and SAT (Site Acceptance Testing) with your equipment. Programs are version-controlled using Git. We use modular programming practices (reusable function blocks and libraries) to reduce errors and improve maintainability.
What is the cost of PLC programming services in South Africa?▼
Costs vary based on project complexity, number of I/O points, program size, and platform. A simple single-machine program may start from R15,000–R30,000. A multi-PLC SCADA-integrated system can range from R80,000–R250,000+. Contact us with your project scope for a detailed, no-obligation quotation.
Get Your PLC Program Developed
Tell us about your control system requirements. Our PLC programming team will assess your needs and provide a tailored proposal within 48 hours.