--- title: "TAS Specification and RFQ: How to Judge Vendors | Citia" description: "A TAS specification starts from processes and documents, then interfaces, failure cases and FAT/SAT tests. Compare terminal automation system vendors fairly." url: https://citia-engineering.com/en/knowledge/tas-specification-rfq language: en updated: 2026-11-13 type: article site: Citia Engineering Indonesia --- # How to write a terminal automation system specification and RFQ Write a TAS specification from processes, interfaces, failure cases and acceptance tests, so proposals from terminal automation vendors can be compared. | Field | Value | | --- | --- | | Topic | Engineering Practice | | Author | Tim Engineering Citia | | Updated | 2026-11-13 | Key takeaways A good terminal automation system (TAS) specification starts from the list of processes and documents the terminal must produce, then derives the field devices, interfaces, system availability and after-sales support from that list. A specification written as a feature wish list invites proposals that tick every box and still fail on site. This guide follows the order an experienced owner's engineer uses for an RFQ (request for quotation) or a KAK (kerangka acuan kerja). If you need the basics first, the INTEGRA TAS product page shows the full gate-to-gate chain, and the article on TAS, TMS and TPS explains where each system's responsibility ends. - A good TAS specification starts from the processes and documents the terminal must produce, then derives field devices, interfaces, availability and support from that list. - The interface list, with an owner and a failure rule for each link, decides more of the project risk than the feature list. - IEC 62381:2024 gives a shared basis for factory and site acceptance tests (FAT, SAT, SIT); write the acceptance criteria into the RFQ, not after award. - Support scope, spare parts, backups and the service provider's security practice (IEC 62443-2-4) belong in the specification from day one. ## Start from processes and documents Write down what the terminal does and what paper it must produce before you write a single technical requirement. Everything else in the specification should trace back to that list. For a fuel terminal the list usually covers receipt, storage, truck loading, gate control and reporting. For each process, name the trigger, the data it needs, the person who approves it and the document it closes with: tank ticket, delivery note, good issue, stock report. Requirements that do not trace to a process are either missing a process or are not needed. - Process inventory: List each process, its trigger, approver and closing document. - Field survey: Record every bay, meter, controller, gate and network cabinet with brand, model and condition. - Interface list: Define each data link, its owner, format and failure rule. - Acceptance criteria: Turn requirements into tests with pass and fail conditions. - FAT, SAT and SIT plan: Agree where and how each test runs, and who signs. - Support and spares: Specify response, backups, spares and the end of the support period. ## The interface list is the core of the specification Most TAS projects that run late are late at an interface, not inside the TAS. Each link between two systems has two owners, two vendors and two ideas of what a message means. For every interface, write the direction of data, the trigger, the message content, the protocol, the owner on each side and what happens when the other side does not answer. The Citia Integrated TAS Portfolio shows a typical set: RFID and gate, a Siemens S7-300 PLC, WebAccess SCADA, INTEGRA TAS and TMS, and SAP with SIOD. Ask bidders to say which side of each interface they will build, and which side they expect the owner or another vendor to supply. - ERP: Orders in, results and postings out - Distribution system: Shipment data, for example SIOD - TMS: Tank stock and tank tickets - Batch controllers: Presets in, batch results out - PLC / SCADA: Pumps, valves, permissives - Gate: RFID, barrier, weighbridge for LPG ## Specify behaviour when something fails A specification that only describes normal operation will get a system that only works in normal operation. Write the failure cases as requirements, each with a test. Three cases cover most of the risk. When the ERP link is down, the terminal should keep loading against orders already received and queue the postings. If the TAS server fails, the specification should say whether a standby server takes over and what happens to a batch in progress. A network drop at one bay should let the running batch finish or stop safely, with no new batch starting. Avoid asking for an availability percentage you cannot test. Ask instead for the switchover procedure, the recovery time you will witness at SAT, and the backup and restore procedure. Ask for a restore, not a backup: A backup that has never been restored is a hope, not a control. Put a full restore of the TAS server onto spare hardware into the SAT, and repeat it once a year under the support contract. ## Acceptance tests: FAT, SAT and SIT Acceptance tests are where the specification is proven, so the tests must be in the RFQ. A bidder prices what you ask it to prove. IEC 62381:2024 sets out requirements and checklists for the factory acceptance test (FAT), an optional factory integration test (FIT), the site acceptance test (SAT) and the site integration test (SIT). Its purpose is to give owner, buyer and vendor one agreed basis for test scope and responsibilities. Use it as the frame and add terminal-specific cases: a full loading with a real truck per product, a gate-to-gate transaction posted to the ERP, and each failure case from the section above. ## Test stages under IEC 62381:2024 - Factory: FAT. Software and panels tested against the specification with simulated signals. - Factory, optional: FIT. Integration with other systems tested before shipment. - Site: SAT. Installed system tested with real field devices. - Site: SIT. End-to-end tests with ERP, TMS and other site systems. ## Support, spares and security in the contract A TAS is used for many years after the project team leaves, so the specification must describe that period too. The contract model decides who answers the phone at night. Citia's support records show what to write down. At Padalarang , faults in equipment outside the TAS contract were often seen as the TAS team's responsibility, so the boundary of scope had to be made explicit. At LPG Panjang , one standby technician covered office hours with on-call support outside them, and recurring communication loss between the weighbridge controller and the weighing house PC needed structured troubleshooting. For security, IEC 62443-2-4:2023 lists the security program requirements an asset owner can ask of an industrial automation service provider during integration and maintenance. Ask bidders which of those requirements they already meet. - Who owns faults after handover: Owner, after warranty | Shared, as written in the LTSA scope | Provider, within the service terms - Changes such as new products: New purchase order each time | Often included up to an agreed limit | Part of the service - Backups and restore tests: Owner's IT team | Scheduled in the LTSA | Provider's responsibility - Main risk: Knowledge leaves with the project team | Unclear scope boundaries | Dependence on one provider ## A checklist for the RFQ When proposals arrive, score them on how well they answer the interface list and the failure cases, not on the length of the feature table. Ask each bidder to name a reference site where the same interfaces run today, and talk to the people who maintain it. - Process and document list: Every process with its trigger, approver and closing document. - Site survey data: Brands, models and condition of all field devices and cabinets. - Interface list: Owner, format, protocol and failure rule for each link. - Failure behaviour: ERP down, server down and bay network loss, each with a test. - Tests and support: FAT, SAT and SIT scope, spares list, response times and restore drills. - Security practice: Remote access rules and the provider's position against IEC 62443-2-4. ## Terms used in this article - RFQ: Request for quotation, the document that asks vendors for priced proposals. - KAK: Kerangka acuan kerja, the Indonesian term of reference for a project. - FAT: Factory acceptance test, run before shipment with simulated signals. - SAT: Site acceptance test, run after installation with real devices. - SIT: Site integration test, end-to-end with other site systems. - LTSA: Long-term service agreement for maintenance and support after handover. - Interface list: Table of every data link between systems, with owners and rules. ## Frequently asked questions Q: What should a TAS RFQ contain at minimum? A: A TAS RFQ should at minimum contain the process and document list, site survey data, the interface list, failure behaviour, acceptance tests and the support scope. Without the interface list and tests, proposals cannot be compared fairly. Q: How do you evaluate terminal automation system vendors? A: Evaluate vendors on how they answer your interfaces and failure cases, and check a reference site that runs the same interfaces. A long feature list matters less than a clear plan for integration, testing and support. Q: What is the difference between FAT and SAT? A: FAT is run at the vendor's facility before shipment with simulated signals; SAT is run on site after installation with real devices. IEC 62381:2024 also defines SIT for end-to-end tests with other site systems. Q: Why should spare parts and backups be in the specification? A: Spare parts and backups must be in the specification because they decide how fast the terminal recovers from a fault. If they are added after award, they are priced without competition and often left out. Q: Which standard covers the security duties of an automation service provider? A: IEC 62443-2-4:2023 covers the security program requirements for service providers that integrate and maintain industrial automation and control systems. It belongs to the ISA/IEC 62443 series. ## Sources and further reading 1. IEC 62381:2024 Automation systems in the process industry: FAT, SAT and SIT, International Electrotechnical Commission (IEC), 2024 (https://webstore.iec.ch/en/publication/67572) 2. IEC 62443-2-4:2023 Security program requirements for IACS service providers, International Electrotechnical Commission (IEC), 2023 (https://webstore.iec.ch/en/publication/67631) 3. ISA/IEC 62443 Series of Standards, International Society of Automation (ISA) (https://www.isa.org/standards-and-publications/isa-standards/isa-iec-62443-series-of-standards) 4. Padalarang TAS lifecycle support, PT Citia Engineering Indonesia, 2026 (https://citia-engineering.com/en/projects/padalarang-tas-lifecycle) 5. LTSA for LPG Panjang, PT Citia Engineering Indonesia, 2022 (https://citia-engineering.com/en/projects/ltsa-for-lpg-panjang) 6. Integrated TAS Portfolio, PT Citia Engineering Indonesia (https://citia-engineering.com/en/products/integrated-tas-portfolio) Preparing a TAS specification?: Send siTia on WhatsApp the outline of your RFQ or KAK, and a Citia engineer can review the interface list and test plan with you. ## Contact - Company: PT Citia Engineering Indonesia - siTia - Virtual Assistance: [WhatsApp +62 813-2206-507](https://wa.me/628132206507). siTia answers questions about our products, projects and enquiries on WhatsApp. Replies are automated, and a person from the Citia team follows up. - Email: services@citiaengineering.com - Phone / WhatsApp (siTia): +62 813-2206-507 - Location: Bandung, Indonesia [Contact Citia](https://citia-engineering.com/en/contact.md) ## Structured data (JSON-LD) ```json { "@context": "https://schema.org", "@graph": [ { "@type": "Organization", "@id": "https://citia-engineering.com/#organization", "name": "Citia Engineering Indonesia", "legalName": "PT Citia Engineering Indonesia", "alternateName": "Citia", "url": "https://citia-engineering.com", "logo": { "@type": "ImageObject", "url": "https://citia-engineering.com/media/citia-logo.png", "width": 950, "height": 328 }, "description": "Citia is an engineering and system integration company in Bandung, Indonesia. We connect field devices, PLC and SCADA, terminal software and enterprise systems, then install, test and maintain them.", "email": "services@citiaengineering.com", "telephone": "+62 813-2206-507", "address": { "@type": "PostalAddress", "addressLocality": "Bandung", "addressRegion": "Jawa Barat", "addressCountry": "ID" }, "contactPoint": [ { "@type": "ContactPoint", "contactType": "customer service", "email": "services@citiaengineering.com", "telephone": "+62 813-2206-507", "url": "https://citia-engineering.com/en/contact" }, { "@type": "ContactPoint", "contactType": "customer support", "name": "siTia - Virtual Assistance", "telephone": "+62 813-2206-507", "url": "https://wa.me/628132206507", "areaServed": "ID", "availableLanguage": [ "id", "en" ] } ], "areaServed": { "@type": "Country", "name": "Indonesia" }, "knowsAbout": [ "Terminal automation system", "Automatic tank gauging", "Tank management system", "SCADA", "Programmable logic controller", "Modbus", "Field instrumentation", "Weighbridge", "Pipeline pressure monitoring", "Industrial IoT" ], "brand": [ { "@type": "Brand", "name": "INTEGRA" }, { "@type": "Brand", "name": "CATALYST" } ], "sameAs": [ "https://www.facebook.com/citiaengineering/", "https://www.instagram.com/citiaengineering/" ] }, { "@type": "WebSite", "@id": "https://citia-engineering.com/#website", "url": "https://citia-engineering.com", "name": "Citia Engineering Indonesia", "inLanguage": [ "en", "id" ], "publisher": { "@id": "https://citia-engineering.com/#organization" }, "potentialAction": [ { "@type": "SearchAction", "name": "Search Citia News", "target": { "@type": "EntryPoint", "urlTemplate": "https://citia-engineering.com/en/news?q={search_term_string}" }, "query-input": "required name=search_term_string" }, { "@type": "SearchAction", "name": "Cari di News Citia", "target": { "@type": "EntryPoint", "urlTemplate": "https://citia-engineering.com/id/news?q={search_term_string}" }, "query-input": "required name=search_term_string" } ] }, { "@type": "WebPage", "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#webpage", "url": "https://citia-engineering.com/en/knowledge/tas-specification-rfq", "name": "How to write a terminal automation system specification and RFQ", "description": "A TAS specification starts from processes and documents, then interfaces, failure cases and FAT/SAT tests. Compare terminal automation system vendors fairly.", "inLanguage": "en", "isPartOf": { "@id": "https://citia-engineering.com/#website" }, "publisher": { "@id": "https://citia-engineering.com/#organization" }, "about": { "@id": "https://citia-engineering.com/#organization" }, "breadcrumb": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#breadcrumb" }, "dateModified": "2026-11-13", "mainEntity": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#entity" } }, { "@type": "BreadcrumbList", "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#breadcrumb", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Citia", "item": "https://citia-engineering.com/en" }, { "@type": "ListItem", "position": 2, "name": "Knowledge", "item": "https://citia-engineering.com/en/knowledge" }, { "@type": "ListItem", "position": 3, "name": "How to write a terminal automation system specification and RFQ", "item": "https://citia-engineering.com/en/knowledge/tas-specification-rfq" } ] }, { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#entity", "url": "https://citia-engineering.com/en/knowledge/tas-specification-rfq", "mainEntityOfPage": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#webpage" }, "@type": "TechArticle", "headline": "How to write a terminal automation system specification and RFQ", "description": "Write a TAS specification from processes, interfaces, failure cases and acceptance tests, so proposals from terminal automation vendors can be compared.", "dateModified": "2026-11-13", "author": { "@id": "https://citia-engineering.com/#organization" }, "publisher": { "@id": "https://citia-engineering.com/#organization" }, "inLanguage": "en", "articleSection": "Engineering Practice", "datePublished": "2026-11-13", "image": "https://revcm.citia-engineering.com/api/v1/public/media/website/cover-d74a6673-15eb-47cc-a2b1-2cbb786fec96.svg" }, { "@type": "FAQPage", "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#faq", "url": "https://citia-engineering.com/en/knowledge/tas-specification-rfq", "inLanguage": "en", "isPartOf": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#webpage" }, "mainEntity": [ { "@type": "Question", "name": "What should a TAS RFQ contain at minimum?", "acceptedAnswer": { "@type": "Answer", "text": "A TAS RFQ should at minimum contain the process and document list, site survey data, the interface list, failure behaviour, acceptance tests and the support scope. Without the interface list and tests, proposals cannot be compared fairly." } }, { "@type": "Question", "name": "How do you evaluate terminal automation system vendors?", "acceptedAnswer": { "@type": "Answer", "text": "Evaluate vendors on how they answer your interfaces and failure cases, and check a reference site that runs the same interfaces. A long feature list matters less than a clear plan for integration, testing and support." } }, { "@type": "Question", "name": "What is the difference between FAT and SAT?", "acceptedAnswer": { "@type": "Answer", "text": "FAT is run at the vendor's facility before shipment with simulated signals; SAT is run on site after installation with real devices. IEC 62381:2024 also defines SIT for end-to-end tests with other site systems." } }, { "@type": "Question", "name": "Why should spare parts and backups be in the specification?", "acceptedAnswer": { "@type": "Answer", "text": "Spare parts and backups must be in the specification because they decide how fast the terminal recovers from a fault. If they are added after award, they are priced without competition and often left out." } }, { "@type": "Question", "name": "Which standard covers the security duties of an automation service provider?", "acceptedAnswer": { "@type": "Answer", "text": "IEC 62443-2-4:2023 covers the security program requirements for service providers that integrate and maintain industrial automation and control systems. It belongs to the ISA/IEC 62443 series." } } ] }, { "@type": "DefinedTermSet", "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#glossary", "url": "https://citia-engineering.com/en/knowledge/tas-specification-rfq", "inLanguage": "en", "isPartOf": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#webpage" }, "name": "Terms used in this article", "hasDefinedTerm": [ { "@type": "DefinedTerm", "name": "RFQ", "description": "Request for quotation, the document that asks vendors for priced proposals.", "inDefinedTermSet": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#glossary" } }, { "@type": "DefinedTerm", "name": "KAK", "description": "Kerangka acuan kerja, the Indonesian term of reference for a project.", "inDefinedTermSet": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#glossary" } }, { "@type": "DefinedTerm", "name": "FAT", "description": "Factory acceptance test, run before shipment with simulated signals.", "inDefinedTermSet": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#glossary" } }, { "@type": "DefinedTerm", "name": "SAT", "description": "Site acceptance test, run after installation with real devices.", "inDefinedTermSet": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#glossary" } }, { "@type": "DefinedTerm", "name": "SIT", "description": "Site integration test, end-to-end with other site systems.", "inDefinedTermSet": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#glossary" } }, { "@type": "DefinedTerm", "name": "LTSA", "description": "Long-term service agreement for maintenance and support after handover.", "inDefinedTermSet": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#glossary" } }, { "@type": "DefinedTerm", "name": "Interface list", "description": "Table of every data link between systems, with owners and rules.", "inDefinedTermSet": { "@id": "https://citia-engineering.com/en/knowledge/tas-specification-rfq#glossary" } } ] } ] } ```