P5 - Develop URS-User-Requirement-Specification

Develop URS-User-Requirement-Specification

Author

CTRL Designer LLC

Published

2024.02.01

1 Introduction

CTRL Designer LLC (CDL) is a leading provider of SBC state-based control (procedural control) based on ISA106 solutions to the process industries.

Its software portfolio and work processes help process control engineers develop an overall process control design and convert it automatically to the selected control system code. These solutions allow users to make smarter decisions to improve safety, reliability, efficiency, and sustainability.

The products are divided into phases:

P1- Industrial Plant Assessment™ (IPA)
P2- Level of Automation (LoA) [Service]
P3- Operating Trends for Excel™
P4- Standard Operating Procedure Analyzer™
P5-URS-to-FRS-Builder-for-Excel™
P6-FRS-Engine-for-Excel™
P7-ACM-Engine-for-Excel™

1.1 CDL Folders

The CDL Package is constructed from the following Folders:

The top folder is called CDL-Product which contains

Project
Tools

1.1.1 Project Folder

The CDL Project folder contains:

CDL-PmName-Project-YYYY
- PmName is the plant name such as VRT
- Project is Optional
- YYYY is the start year is is optional
Example is CDL-VRT-2023

The Project folder contains:

P1-IPA-Industrial-Plant-Assessment
P2-LofA-Level-Of-Automation
P3-OT-Operational-Trends
P4-SOP-Standard-Operating-Procedure
P5-URS-User-Requirement-Specification
P6-FRS-Functional-Requirement-Specification
P7-ACM-Automatic-Code-Maker

Each represent a PHASE of the project.

1.1.2 Tools Folder

The CDL Tools folder contains:

A-Documentation
B-Templates
C-CM-CCM-Libraries
D-Engines
E-Issues

2 State-Based Control – ISA106

ISA106 develops standards, recommended practices, and technical reports on the design and implementation of procedures for automating continuous process operations. The ISA106 committee has also published two technical reports and is in the process of developing a standard address to topics that include:

models and terminology
modularization of procedural steps to foster reuse and lower the total cost of ownership
exception handling for abnormal situations
physical, procedural, and application models
process unit orientation with an operational perspective
recommended best practices
implementation of start up, shutdown, abnormal situations, hold states, and transition logic
recommended target platform (i.e., control system versus safety system) for different types of procedures
life-cycle management best practices
training and certification best practices

The main driver for ISA106 is to enable the control engineer to implement:

the repeatable and optimized start-up, run, state transition, and shutdown procedures
abnormal situation management using additional control strategies
intelligent alarming based on the mode of operation
equipment, devices, and controllers that are automatically enabled based on the mode of operation
redundant equipment (such as pumps) that can be automatically swapped for maintenance, run-time balancing, failure recovery, or other reasons
control systems that allow operators to run a unit as a unit instead of manipulating individual devices
start up and shutdown procedures (which may be infrequent), including automatic sequencing of the plant (unit to unit)

2.1 Models and terminology

The ISA106 Standard written by the ISA106 committee, Procedure Automation for Continuous Process Operations - Models and Terminology, complements the concepts described in several key ISA standards. It addresses the subject of procedural automation for continuous process operations and is focused on a collection of good practices regarding procedural automation in process operations and strategies for incorporating automated procedures into industrial automation and basic process control systems (BPCS). Other standards deal with the use of procedures in specific applications, among them batch processing and safety systems.

Many of the fundamental concepts discussed in these standards are common to all procedures independent of the context, but there are requirements specific to certain continuous processes. Those requirements are addressed in the procedure requirements model, the procedure implementation model, and the physical model, as well as in the sub-clause concerning the mapping of procedures to BPCS components.

The scope of the standard is to provide the knowledge, best practice application, and language (including terms and definitions) that will enable organizations to apply procedural automation across diverse continuous process industries.

This document focuses on automated procedures that primarily reside on systems within the supervisory control, monitoring, and automated process control section of the production process. This technical report does not concur with procedure execution at the operations management functional level. It does, nonetheless, focus on continuous processes. However, the contents of the report may be used in other types of process control, such as batch or discrete. The technical report is intended to be applicable to process control activities within the BPCS and safety instrumented systems. Required safety instrumented functions should be analyzed and implemented following ISA-61511 (ISA-84).

Three models are defined for procedural automation of continuous process operations.

1- Physical model

The physical model depicts how the ISA-95 role-based equipment model is applied to continuous process operations within this technical report.

2- Procedure requirements model

The procedure requirements model depicts how procedure requirements map to the hierarchy of equipment shown in the physical model.

3- Procedure implementation model

The procedure implementation model serves as the connection between the procedure requirements model and the physical model.

3 CDL-ISA106

3.1 Introduction

CTRL Designer LLC (CDL) provides a comprehensive step-by-step workflow to implement procedural automation:

CDL Tools for Excel™: A set of Microsoft Excel program
ISA106 Implementation Guide: Being published on Amazon
ISA106 Work Process Implementation: Converting existing company work process

ISA106 Procedures for continuous process operations include situations of start-up, shutdown, abnormal situations, hold step, and transitions of process feed/output. These standard operating procedures (SOP) exist in manual form, probably written, before automation. The goals are to increase uniformity and consistency of procedure automation and reduce the risk, cost, and errors associated with automating procedures.

The ISA106 work process can be mapped to

Front-end Loading (FEL)
V-model (GAMP)

3.2 Front-end Loading (FEL)

Front-end Loading (FEL), also referred to as front-end engineering design (FEED), is the process for conceptual development of projects in processing industries such as upstream oil and gas, petrochemical, natural gas refining, extraction metallurgy, waste-to-energy, and pharmaceuticals. This involves developing sufficient strategic information with which owners can address risk and make decisions to commit resources to maximize the potential for success.

The FEL is divided into three stages:

3.2.1 Front-End Load – Options Study – FEL1

This answers the question, “What are my options to achieve my project goals?”. For example, in nickel ore processing. This stage would study both options and recommend the best one based on the specific project requirements.

3.2.2 Front-End Load – Feasibility Study – FEL2

The selected option is developed up to a pre-defined level of detail not yet sufficient for construction and operation, but enough to develop a cost estimate, and a schedule estimate, and to make any critical decisions that will influence the final design of the plant.

3.2.3 Front-End Load –Front-End Engineering Design – FEL3

The engineering team will now fully design the plant, including the exact specifications for how it will be constructed, commissioned, started up, and operated. The proposed plant will now have a detailed cost estimate and construction schedule.

3.3 V-model

In software development, the V-model represents a development process that may be considered an extension of the waterfall model and is an example of the more general V-model. Instead of moving down linearly, the process steps are bent upwards after the coding phase to form the typical V shape.

The V-Model demonstrates the relationships between each phase of the development life cycle and its associated phase of testing. The horizontal and vertical axes respectively represent time or project completeness (left-to-right), and level of abstraction (coarsest-grain abstraction uppermost).

The V-model is a graphical representation of a system development life cycle. It is used to produce rigorous development life cycle and project management models. The V-model falls into three broad categories, the German V-model, a general testing model, and the US government standard.

Task	Definition
URS	User Requirement Specification
FRS	Functional Requirement Specification
DDS	Unit Detailed Design Specification
IAT	Internal Accepting Testing (vs DDS)
FAT	Factory Acceptance Testing (vs FRS)
SAT	System Acceptance Testing (vs URS)

The development of the V-model is divided into three parts:

User Requirements Specification (URS)
Functional Requirements Specification (FRS)
Detailed Design Specification (DDS)

3.3.1 User Requirements Specification (URS)

URS is a document that defines the purpose and justification of the procedural automation that the user plans to build (or modify). It provides specific, measurable performance criteria. The URS is not a “How to do” document but a: “What to do” document.

3.3.2 Functional Requirements Specification (FRS)

FRS is a document that describes what the end-users want the control system to do to satisfy the URS requirements. It is NOT how the control system works. It includes input/output (IO), Step/Transitions definition, and IO allocation to CM and CCM Libraries. It is a document that specifies the functionality of an implemented control system.

3.3.3 Detailed Design Specification (DDS)

DDS is a collection of CM and CCM and their associated IO and parameters to be used as part of the implementation. The DDS contains all the information required to build the control system based on FRS.

3.4 V-Mode and its relationship with FEL

A detailed V-Model that is being used by the CDL tools for Excel(TM) is shown below:

3.5 CDL tools and workflow

CDL tools and workflow is divided into the following phases:

User Requirements Specification (URS)
Functional Requirements Specification (FRS)
Detailed Design Specification (DDS)

4 User Requirements Specification (URS)

4.1 Purpose

The purpose of the URS phase is to develop a document that contains

Collect Plant Information
- A1-Process-Description
- A2-Process-Control-Objectives
- A3-Level-of-Automation
- A4-PA-UM-Process-Diagram
- A5-Start up-Run-Shut Down (OT)
Collect IO and Divide into UM
- B1-Instrumentation
- B2-PA-UM-Definition

4.2 Step by Step

Do the following steps:

4.2.1 A1-Process-Description

Define the following in the URS {A1-Process-Description} worksheet:

Describe The Process
Define Feeds
Define Products
Define Units (UM) Draft
Define Major Recycle Stream

4.2.2 A2-Process-Control-Objectives

Define the following in the URS {A2-Process-Control-Objectives} worksheet:

Safety
Environmental Protection
Equipment Protection
Smooth Plant Operation
Product Quality
Profit Optimization
Monitoring and Diagnosis
References

4.2.3 A3-Level-of-Automation

Review the following in the URS {A3-Level-of-Automation} worksheet:

The following objects - Pumps - Block-Valves - Control-Valves - Step-Transition Each of the object can be assigned to

Level of Automation 1 - Manual Control [not brought into the DCS]
Level of Automation 2 - Basic Level of Control
Level of Automation 3 - Medium Level of Control
Level of Automation 4 - Normal Level of Control
Level of Automation 5 - High Level of Control

4.2.4 A4-PA-UM-Process-Diagram

Review the following in the URS {A4-PA-UM-Process-Diagram} worksheet: Please execute the following tasks

Divide Plant into Units

Task	Definition
1	Identify major equipment(distillation, reactor, compressor)
2	Identify associated equipment(the only purpose is to develop a list of the major equipment (reboiler, pump, condenser)
3	Starting from the feed, move forward until you reach either - Major equipment or - A point where the stream splits to support more than one piece of major equipment
4	If the selected portion of the plant needs to be Startup/Run/Shutdown independent of the downstream major equipment, that defines a unit (for example – Feed system supplying 2 or more reactors)
5	Identify local recycles (associated equipment) - Identify major breakpoints (stream leaving the unit) - The area between breakpoints in streams is a unit.
6	Name the unit according to the major equipment it contains if available, or a descriptive name (for example steam header)

Draw a simplified overview of the process that
- Shows only major equipment and key flows between
- This is easier to follow than a typical indexed flow sheet
Draw major flows (connecting unit to unit)
Draw major recycle (unit to unit, not the internal to the unit)
Add Stream numbers for major flows
Add the following information to a table

normal operation flow rates
normal operation pressure
normal operation temperature

4.2.5 A5-Start up-Run-Shut Down

Develop the following in the URS {A5-Start up-Run-Shut Down} worksheet:

Divide the Plant into Process Units (UM)
Review ISA106 Physical Model definition.
Develop the Plant Physical Model (PM).
Review of Standard Operating Procedure (SOP) and P&ID.
Develop Plant/Plant Area OT
- Plant Operation Trend,
- Modes of Operation Matrix,
- Dynamic Flow-sheets for:
  - Startup
  - Run
  - Abnormal Situation Management
  - Controlled Shut Down
Copy the Plant operation trend to this sheet

4.3 B1-Instrumentation

Add instrumentation data in the URS {B1-Instrumentation} worksheet:

Please fill only columns 1 (A) to 8 (H) at the URS level.

Note: Please review the CDL Book of Convention

Using UM names defined previously, add the information to the column 4 (D)
- Master: UM is developed such that it will be copied to another UM Copy (used 2 to many)
- Stand-Alone: UM is developed as a stand-alone (used once)
- Copy: Um code is copied from its master (IO will be changed)

Add the following information
- UM Library Name
- Um Instantiated Name (i-Name)
- Description
- Process Control Engineer Name

Review the IO allocated to each unit

Where
- IO Complexity is Sum(Number of IO)/(Number of AO)
- IO Multiplier is defined as:
  - 1.00 for Stand-Alone
  - 1.25 for Master (need 25% more work for developing it)
  - 0.40 for Copy
- The IO Eq (IO Equivalent = IO * IO Multiplier
Review and adjust the level of automation
- Select the Unit type in column 17
- The overall CDL raking is displayed in column 18
- You can change them in column 19
- The IO EQ* is calculated as IO EQ * LoA Multiplier

The following table summarizes the results:

What	Total Number	%
IO	227	100%
IO EQ	173	76%
IO EQ*	273	120%

Therefore for cost calculation use the IO EQ* numbers.

Project Cost Calculations:

Fill in the following information

The green background color cells can be modified.

The program will display the following:

Assuming that the overall project estimated cost is $100,000,000 then

5 URS Engine

The URS Engine provides all of the functionality to develop the URS document.

These ar e the steps

Open the URS engine and do the following steps:
Select the folder
List URS files
Imported URS file
Add information
Import IO
Build PA-UM
Build FRS files
Export URS file

5.1 Select the folder

5.2 2- List URS files

Click the [2] List Files button
This will list all of the files
- Add X in front of the URS file to be edited

5.3 3- Imported URS file

Click the [3] Import PS-URS file button

This will import all worksheets from the selected URS file

N	Sheet
1	A1-Process-Description
2	A2-Process-Control-Objectives
3	A3-Level-of-Automation
4	A4-PA-UM-Process-Diagram
5	A5-Start up-Run-Shut Down
6	B1-Instrumentation
7	B2-PA-UM-Definition
8	B3-UM-Limits