Procedure Automation for Continuous Process Operations

A Practical Guide to IEC-TBD (CDL Procedural Automation)

Author

Yahya Nazer

Published

October 15, 2026

Book cover

Yahya Nazer · CTRL Designer LLC

IEC-TBD / CDL Procedural Automation Educational Series

This book is provided to the International Electrotechnical Commission (IEC) to support the development of a standard. Yahya Nazer is the team leader for the development of this standard.

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Abstract: Procedure automation converts the manual operating procedures of continuous process plants - start-up, shutdown, transitions, hold steps and abnormal situation handling - into automated sequences executed by the basic process control system. This book explains the IEC-TBD (CDL Procedural Automation) framework in practical terms: its models, the State-Based and Sequence-Based automation styles, the lifecycle management and procedure automation strategies, and the full procedure automation lifecycle from specification and design through implementation, operation and retirement. Industrial examples from refineries, chemical plants and power generation illustrate every requirement.

Keywords: automation style, BPCS, continuous process, control module, front-end loading, IEC-TBD, CDL Procedural Automation, ISA-95, lifecycle management, metrics, procedure automation, procedure model, requirements, Sequence-Based Control, SqBC, State-Based Control, SBC, sequential function chart, step, transition

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IEC-TBD is a proposed IEC standard that has not yet been assigned a number. ANSI/ISA-95 is published by the International Society of Automation (ISA). These names are used here for identification only; no endorsement by IEC or ISA is implied.

No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.