Custom Vendor-Independent SCADA/HMI Software to Replace Siemens WinCC for ~30-Axis Kinetic Canopy
Budget: $10,000 – $35,000 USD
Overview
We are commissioning a custom, vendor-independent supervisory control / HMI software application to replace an existing Siemens WinCC SCADA layer. The system operates a large kinetic retractable shade canopy with approximately 30 independently-driven axes. This is a software-only engagement: all field equipment stays in place and unmodified, and is integrated with solely via the existing PLC. The site is in the Gulf / Middle East region; exact identity is shared only with shortlisted bidders under NDA.
What we need
A new application that runs on the existing on-site industrial PC (no new production hardware) and communicates with the PLC over Ethernet using the S7 protocol (e.g. a snap7-class library), reading and writing an agreed tag set — possibly via a non-optimised "mirror" data block. The existing automation comprises a Siemens S7-300 fail-safe PLC (CPU 317F-2 PN/DP class); ET200S distributed I/O including an RS-485/serial-ASCII module carrying weather data; per-axis variable-speed drives (SINAMICS class); encoders and position switches; weather station(s); and managed Ethernet/PROFINET switches. Hard safety interlocks remain in the certified fail-safe PLC; the software provides monitoring, operator alerting and supervisory commands. The exact tag map and the safety boundary between PLC and software are confirmed in a requirements/discovery phase. The technology stack below is indicative only — bidders are invited to propose and justify their own.
Key functional requirements
- PLC communication and cyclic data acquisition; robust handling of link loss with safe behaviour and automatic reconnection.
- All canopy operating modes: Open; Close-Inline; Close-Shifted; Chess/alternating pattern (sequential and parallel variants); Emergency Retract; Service/Manual per-axis; Cleaning-position mode (a software positioning mode only — not a physical cleaning service).
- Wind/weather monitoring with supervisory safety behaviour: normal = all operations; elevated = retract-only; high = automatic retract; sensor loss = immediate retract.
- Alarm and event management: priority classification, acknowledgement workflow, history, search.
- Web-based operator dashboard: real-time 2D top-view of all ~30 axes plus a complementary 3D WebGL view of current canopy state; responsive and usable on tablets via browser.
- User management with Administrator and Operator roles; TOTP two-factor authentication; full audit log.
- Automated monthly PDF reporting plus on-demand export.
- Relational database (e.g. PostgreSQL) and time-series historian (e.g. InfluxDB); local backup and restore.
- Real-time push updates (~100 ms) via WebSocket.
- Bilingual English/Arabic with RTL support is desirable — please price separately as an option.
Deliverables
Working application deployed on the on-site industrial PC; complete source code, build scripts and a reproducible build; Software Bill of Materials (SBOM); architecture document and functional specification; operator user manual and training; FAT and SAT test plans and results; a perpetual licence to (or assignment of) the application software, with the right to operate, modify and self-maintain it after the warranty.
Out of scope
Changes to the PLC safety program or any field equipment/wiring; CCTV/video; native mobile apps; cloud/IoT-platform integration; photorealistic rendering or AR/VR; BMS/BACnet integration; OPC UA server; AI/predictive maintenance; and all physical, mechanical, civil, fabric, cleaning and maintenance works.
Engagement & warranty
Fixed-price, milestone-based. Suggested milestones: M1 requirements + architecture sign-off + tag-map confirmation; M2 PLC and weather drivers; M3 core control logic + dashboard alpha; M4 integration + FAT + SAT preparation; M5 on-site commissioning and deployment; M6 acceptance and go-live. A 24-month warranty is required, with P1/P2/P3 support response tiers. Most work is remote; on-site commissioning in the Gulf/Middle East region is required (a few short trips). State whether travel/accommodation is included or reimbursable.
How to bid
Submit a fixed-price proposal broken down by the six milestones, with the Arabic/RTL option priced separately. Include your proposed architecture and stack with justification, your approach to the PLC safety boundary, an indicative schedule, and answers to ALL questions below. Proposals that do not address the questions will not be considered. Bid deadline: 15 July 2026. Questions to: via Freelancer chat only.
Questions every bidder must answer:
1. Describe a project where you replaced or supplemented a Siemens WinCC (or comparable vendor SCADA) layer with a custom application talking to an S7-300/400 PLC over the S7 protocol. Which library (snap7-class or other), and how did you map and validate the tag set on a live PLC?
2. How have you implemented supervisory logic alongside a certified fail-safe PLC without altering the safety program — defining and respecting the boundary between PLC interlocks and software-side commands? Give a concrete example.
3. Describe your approach to supervising multi-axis coordinated motion (~30 independently-driven axes, with sequential and parallel pattern modes) and guaranteeing safe, deterministic behaviour on PLC link loss and reconnection.
4. What is your tested approach to integrating weather/environmental data (including serial/RS-485 ASCII sources) and driving threshold-based supervisory responses such as retract-only and automatic-retract?
5. Provide one or two comparable delivered systems (sector, scale, axis/point count, your role), including FAT/SAT execution and acceptance criteria.
6. How will you deliver real-time (~100 ms) WebSocket dashboards combining a live 2D top-view and a 3D WebGL view, with acceptable performance on tablet browsers?
7. Confirm your ability to deliver full source code, a reproducible build and an SBOM, and to support a 24-month warranty with P1/P2/P3 tiers. State your on-site commissioning capability for the Gulf/Middle East region and how travel is handled.
NDA & next steps
Exact site identity, the full PLC tag map and operating documentation are confidential and shared with shortlisted bidders under a mutual NDA. A paid requirements/discovery phase (M1) precedes any firm fixed quotation. Shortlisting is based on demonstrated Siemens/PLC/SCADA integration experience, safety-relevant supervisory delivery, and comparable references.
We are commissioning a custom, vendor-independent supervisory control / HMI software application to replace an existing Siemens WinCC SCADA layer. The system operates a large kinetic retractable shade canopy with approximately 30 independently-driven axes. This is a software-only engagement: all field equipment stays in place and unmodified, and is integrated with solely via the existing PLC. The site is in the Gulf / Middle East region; exact identity is shared only with shortlisted bidders under NDA.
What we need
A new application that runs on the existing on-site industrial PC (no new production hardware) and communicates with the PLC over Ethernet using the S7 protocol (e.g. a snap7-class library), reading and writing an agreed tag set — possibly via a non-optimised "mirror" data block. The existing automation comprises a Siemens S7-300 fail-safe PLC (CPU 317F-2 PN/DP class); ET200S distributed I/O including an RS-485/serial-ASCII module carrying weather data; per-axis variable-speed drives (SINAMICS class); encoders and position switches; weather station(s); and managed Ethernet/PROFINET switches. Hard safety interlocks remain in the certified fail-safe PLC; the software provides monitoring, operator alerting and supervisory commands. The exact tag map and the safety boundary between PLC and software are confirmed in a requirements/discovery phase. The technology stack below is indicative only — bidders are invited to propose and justify their own.
Key functional requirements
- PLC communication and cyclic data acquisition; robust handling of link loss with safe behaviour and automatic reconnection.
- All canopy operating modes: Open; Close-Inline; Close-Shifted; Chess/alternating pattern (sequential and parallel variants); Emergency Retract; Service/Manual per-axis; Cleaning-position mode (a software positioning mode only — not a physical cleaning service).
- Wind/weather monitoring with supervisory safety behaviour: normal = all operations; elevated = retract-only; high = automatic retract; sensor loss = immediate retract.
- Alarm and event management: priority classification, acknowledgement workflow, history, search.
- Web-based operator dashboard: real-time 2D top-view of all ~30 axes plus a complementary 3D WebGL view of current canopy state; responsive and usable on tablets via browser.
- User management with Administrator and Operator roles; TOTP two-factor authentication; full audit log.
- Automated monthly PDF reporting plus on-demand export.
- Relational database (e.g. PostgreSQL) and time-series historian (e.g. InfluxDB); local backup and restore.
- Real-time push updates (~100 ms) via WebSocket.
- Bilingual English/Arabic with RTL support is desirable — please price separately as an option.
Deliverables
Working application deployed on the on-site industrial PC; complete source code, build scripts and a reproducible build; Software Bill of Materials (SBOM); architecture document and functional specification; operator user manual and training; FAT and SAT test plans and results; a perpetual licence to (or assignment of) the application software, with the right to operate, modify and self-maintain it after the warranty.
Out of scope
Changes to the PLC safety program or any field equipment/wiring; CCTV/video; native mobile apps; cloud/IoT-platform integration; photorealistic rendering or AR/VR; BMS/BACnet integration; OPC UA server; AI/predictive maintenance; and all physical, mechanical, civil, fabric, cleaning and maintenance works.
Engagement & warranty
Fixed-price, milestone-based. Suggested milestones: M1 requirements + architecture sign-off + tag-map confirmation; M2 PLC and weather drivers; M3 core control logic + dashboard alpha; M4 integration + FAT + SAT preparation; M5 on-site commissioning and deployment; M6 acceptance and go-live. A 24-month warranty is required, with P1/P2/P3 support response tiers. Most work is remote; on-site commissioning in the Gulf/Middle East region is required (a few short trips). State whether travel/accommodation is included or reimbursable.
How to bid
Submit a fixed-price proposal broken down by the six milestones, with the Arabic/RTL option priced separately. Include your proposed architecture and stack with justification, your approach to the PLC safety boundary, an indicative schedule, and answers to ALL questions below. Proposals that do not address the questions will not be considered. Bid deadline: 15 July 2026. Questions to: via Freelancer chat only.
Questions every bidder must answer:
1. Describe a project where you replaced or supplemented a Siemens WinCC (or comparable vendor SCADA) layer with a custom application talking to an S7-300/400 PLC over the S7 protocol. Which library (snap7-class or other), and how did you map and validate the tag set on a live PLC?
2. How have you implemented supervisory logic alongside a certified fail-safe PLC without altering the safety program — defining and respecting the boundary between PLC interlocks and software-side commands? Give a concrete example.
3. Describe your approach to supervising multi-axis coordinated motion (~30 independently-driven axes, with sequential and parallel pattern modes) and guaranteeing safe, deterministic behaviour on PLC link loss and reconnection.
4. What is your tested approach to integrating weather/environmental data (including serial/RS-485 ASCII sources) and driving threshold-based supervisory responses such as retract-only and automatic-retract?
5. Provide one or two comparable delivered systems (sector, scale, axis/point count, your role), including FAT/SAT execution and acceptance criteria.
6. How will you deliver real-time (~100 ms) WebSocket dashboards combining a live 2D top-view and a 3D WebGL view, with acceptable performance on tablet browsers?
7. Confirm your ability to deliver full source code, a reproducible build and an SBOM, and to support a 24-month warranty with P1/P2/P3 tiers. State your on-site commissioning capability for the Gulf/Middle East region and how travel is handled.
NDA & next steps
Exact site identity, the full PLC tag map and operating documentation are confidential and shared with shortlisted bidders under a mutual NDA. A paid requirements/discovery phase (M1) precedes any firm fixed quotation. Shortlisting is based on demonstrated Siemens/PLC/SCADA integration experience, safety-relevant supervisory delivery, and comparable references.