ASP ENGINEERING LIBRARY
A clearer path through your next project.
Start with the decision you need to make. These reading paths connect the fundamentals, implementation details, and checks that matter on site.
For integrators & IT/OT teams
Connect machines & data
Make plant data trustworthy, from PLC to business system.
- OPC UA Protocol OverviewOPC Unified Architecture (OPC UA) , defined by IEC 62541, is the platform-independent, service-oriented architecture for secure, reliable data exchange in industrial automation. It is the su…
- Kepware Driver Selection and Channel/Tag ArchitectureKEPServerEX is the most widely deployed industrial connectivity platform: it converts dozens of native protocols — Siemens, Allen-Bradley, Modbus, DNP3, BACnet, and hundreds more — into OPC…
- OPC UA Subscription Sizing: Sampling, Publishing, and QueuesAn OPC UA subscription should deliver the changes a client needs without making every signal run at the fastest available rate. Size it around process dynamics, client refresh needs, and the…
- Industrial Tag Naming and Data Contracts for PLC, SCADA, and MESA tag name is an identifier; a data contract explains what that identifier means and how it behaves. Agree both before connecting PLC, SCADA, historian, and MES systems. This prevents differ…
- OPC UA to MQTT Bridge PatternsIndustrial automation environments increasingly demand a two-tier data strategy: OPC UA for real-time, deterministic plant-floor communication and MQTT for scalable, firewall-friendly edge-t…
For plant & project engineers
Modernize a control system
Scope the change, protect production, and plan the handover.
- DCS vs. PLC — A Comprehensive Selection Guide for Process ApplicationsSelecting the right control platform is one of the most consequential decisions in any industrial automation project. This guide provides a structured methodology for choosing between Distri…
- Control System Modernization: Retrofit and Migration PlanningIndustrial plants run on control systems with lifecycles measured in decades, but the underlying platforms age faster: processors reach end of life, operating systems lose security support,…
- Automation RFQ Checklist: Writing a Scope That Suppliers Can PriceAn automation request for quotation is useful when competing suppliers price the same deliverables and assumptions. Start with the process problem and installed equipment, then specify inter…
- Brownfield Automation Cutover: Planning the Point of No ReturnA brownfield cutover plan is a sequence of controlled changes with explicit decisions about whether to continue or return to the previous system. It must account for production state, people…
- SCADA System Backup and Disaster Recovery PlanningEvery SCADA system will eventually fail — a hard disk dies, an upgrade corrupts a database, a fire or ransomware encrypts the servers. The difference between an outage and a catastrophe is t…
For commissioning & maintenance teams
Commission with confidence
Turn requirements into repeatable checks and acceptance evidence.
- Machine Commissioning: FAT, SAT and Startup ChecklistsCommissioning is the structured process of proving that a machine or system works as designed — from the first power-on to productive operation. In automation projects, commissioning is orga…
- PLC I/O Wiring and Termination Best PracticesThe quality of a control system's field wiring determines its reliability more than any other installation factor. Most "PLC faults" that appear in the first year of operation — intermittent…
- 4–20 mA Loop Commissioning: From Test Input to HMI ValueAn analog loop check confirms that a known input produces the expected value and diagnostic behavior through the measurement chain. It is different from calibrating a sensor or proving the p…
- OPC UA Data Quality and Timestamps: Avoiding Stale-Value DecisionsA process value is useful only when the receiver can tell whether it is valid and current enough for its purpose. In OPC UA, keep the value, StatusCode, and timestamps together through the g…
- Automation Handover Package: What Operations Needs After CommissioningAn automation handover should let the operating team understand, maintain, and recover the delivered system without depending on an engineer’s laptop. Organize the package around actual oper…
For OT owners & security teams
Build a resilient OT network
Understand assets, control access, and prove recovery.
- OT Asset Inventory and Network DiscoveryOT asset inventory — knowing exactly what hardware and software is running on the industrial network — is the foundation of OT security and maintenance. You cannot protect, patch, or even re…
- OT Network Segmentation Using the Purdue ModelThe Purdue Enterprise Reference Architecture , also known as the ISA-95 / IEC 62264 functional hierarchy, provides the foundational model for OT network segmentation. Proper segmentation is…
- Secure Remote Access for OT EnvironmentsSecure remote access is one of the most contentious topics in OT security. Vendors, integrators, and internal engineers all need to reach plant systems — for commissioning, support, and afte…
- OT Backup Restore Tests: Proving Recovery Before an OutageA backup is a recovery input, not evidence that recovery will work. A restore test checks whether the organization can rebuild the required function within agreed time and data-loss limits.…
- OT Vendor Remote Access: An Approval and Closeout WorkflowVendor access to an industrial system should be an approved activity with a named person, defined target, limited duration, and visible outcome. A permanent tunnel shared by several supplier…
FROM REFERENCE TO REAL PROJECT
Bring your next automation challenge.
PLC and DCS engineering, OPC connectivity, and digital transformation. Start with your installed systems, your constraints, and what you need to achieve.