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Safeguarding your Plant Automation

with Change Management

Best practices for safeguarding plant automation systems from

PLC failure, human error and other common hazards with

Change Management.


Safeguarding your Plant Automation with Change Management


The increased use of plant floor automation to achieve production goals has created a dependency on

PLCs, PC control systems and programmable automation. These devices and their logic programs are

costly to develop but vital to the running of the plant and are viewed by most companies as corporate

assets. It is incumbent on plant and corporate management to ensure that proper safeguards are in

place to protect and manage change in these assets. This paper examines the sources and types of

changes that take place in plant automation environments, and the considerations and approaches

necessary to safeguard your automation systems through the effective use of a Change Management

System (CMS).


Georgetown University defines change management as the complete set of processes employed to

ensure that changes are implemented in a visible, controlled and orderly fashion. (1) Focus should be

placed on several key elements:

1. Process: Must be a structured method that stays the same

2. Completeness: Must include all objects (person, place or thing)

3. Visibility: Without visibility, Change Management doesn’t exist

4. Control: Who, what and where

5. Order: Changes may need a particular sequence to be effective

Change Management as it applies to plant automation focuses on the control systems that operate the

production equipment. Change Management System (CMS) applications have matured over the past

20 years along with the increases in sophistication and capability of the automation devices and

control software developed by automation vendors.

There are many elements of a CMS that make its function distinct from single-file-based source code

control systems, with the most distinct differences being a suite of tools to manage a group of files

(often referred to as a “project”) as a single entity, and processes for detecting source code changes

outside of source code control. In most automation devices the entire project file is necessary when

managing revisions and identifying changes.



Safeguarding your Plant Automation with Change Management


An automation Change Management System is a centralized system that manages changes to

program logic for controls programs and devices such as PLCs, CNCs, HMIs, PC control systems,

robots, drives and general automation programs. A typical small plant will have a few hundred

programs that should be managed, while large plants will have several thousand. Over the life of a

facility the investment in program logic alone represents a significant expenditure that should be

preserved and optimized. In order to do this a CMS should have the following features:

• An archive of prior revisions of programs

• The ability to detect changes

• Tools for documenting changes and making them visible to users

• A historical record of who made the change, when, and from where it was made

• Secured user and workstation access

• Features for controlling editor operations mapped to user permissions

• Procedures for recovering from hardware failures

Change notification

As automation devices have grown more complex and have incorporated more plant data in their

operation, there is an increase in the need to make adjustments to variables and logic to continue

smooth operation. These adjustments may be minor individually but are directly linked to machine

throughput and uptime. If the current device program and configuration are lost, and an old version of

the device program must be used, the result is decreased machine performance, decreased quality

and/or downtime. While this situation is costly enough, consider the ramifications to plant operation if

there are no older versions of a lost program available and the program must be completely rewritten.

This can and does happen, and the effects can significantly impact safety and plant throughput for

months. These impacts added to the cost to re-rewrite, test and commission a single program is often

greater than the cost to implement a plant-wide CMS product.

Consider the ramifications to plant

operation if there are no older versions

of a lost program available and the

program must be completely rewritten.



Safeguarding your Plant Automation with Change Management


Each facility has a unique set of change types and frequencies that can affect a CMS strategy. A

selected set of activities is outlined here to prompt further thought and highlight the need for a proper

implementation of a CMS in order to achieve optimum results.

• Nature and Frequency of Changes: It is important to ensure that an adequate number of program

copies are available (including the “as delivered” copy from the vendor/integrator) to ensure that

changes can be classified and reviewed. Some changes represent true improvements, while others

highlight a process problem or training issue that should be addressed by other means.

• Process Enhancements: If changes are made in the process that make prior versions of the

program obsolete, these enhancements should be clearly identified so that users do not

revert to an older version of a program to fix a new issue. Plant operating guidelines should

identify when the deletion of prior programs is warranted, and which users will have this


• Unmanaged Changes: Without a CMS the controls engineer would use the editor software

on a workstation or laptop to make changes in a device. If multiple people make changes

from multiple computers (as is especially common in multi-shift operations) the

documentation of changes is often lost. Using a CMS to compare the program running in

the device with the last recorded version, a facility can identify changes that were made

outside of the CMS. Once the CMS is implemented and sufficient device networking is in

place, edits outside the CMS should be discouraged. These unmanaged edits are often

prohibited in more regulated facilities using a CMS.

• Temporary Changes: It is common to make a “temporary” change to a program to resume

operation while a maintenance task is performed on a failed component. It is also common

for these temporary bypasses to be forgotten, which can result in serious safety issues. A

CMS is used to note these temporary changes and provide a means of easily restoring a

prior version of the program once maintenance is complete.

• Multi-Process or Recipe Operations: In facilities that run different processes or recipes it is

important to manage which version of a program is being updated. The creation of

specialized copies of programs to use as “master versions” for each of these processes can

aid in managing them efficiently.



Safeguarding your Plant Automation with Change Management


There are many individuals in a facility with the need to make automation changes. Each of their roles

and the unique characteristics of the changes they make to the automation layer should be considered.

This enables roles to be established in the CMS to manage who can make certain types of changes. For

example, some users will have the ability to go online and monitor a device operation, another group will

be able to make changes to the program, while others can delete older programs, change the program in

use to an alternate version or compare changes between versions of programs. A representative list of

user classes is outlined below, along with typical types of changes and plant considerations.

• Engineering: Often an engineer is concerned with process improvement, and will make

enhancements to the automation systems to increase throughput, visibility, reliability, etc.

Engineers will need the ability to modify the running program, change to an alternate version of a

program and compare versions of programs for differences.

• Maintenance Technicians: One of the primary reasons for maintenance technicians to make

program changes is to deal with a failed or degraded component that is impacting production. This

could be a sensor that is reading incorrectly or a contact that has malfunctioned. Technicians will

often need to “bypass” an input to the program while repairs are carried out, and the need to

identify those temporary bypasses to ensure they are removed is a key benefit of a CMS.

• Contractors: Many organizations will utilize contractors to perform functions that require

specialized skills that are not retained in-house. A CMS will provide the facility with the ability to

manage the permissions granted to contractors and detect changes made by them.

Technicians will often need to “bypass” an

input to the program while repairs are carried

out, and the need to identify those temporary

bypasses to ensure they are removed is a key

benefit of a CMS.

• OEMs: When the Original Equipment Manufacturer is in the facility installing or updating their

equipment it is vitally important to capture the “as delivered” program copy and save that as a

reference version in the CMS. This reference can be invaluable when identifying problems with the

machinery and working with the OEM on corrective actions. The reference copy can be compared

to other versions of the program to identify not only the specific changes, but also enable experts



Safeguarding your Plant Automation with Change Management

to spot trends in the changes which often point to training or raw material issues.

• Operators: The typical change that an operator would make to an automation program would be to

switch between versions of the stored program when production objectives change. Having a log

showing the history of these changes can often be useful.

• Administrators: A CMS administrator will be involved in implementing plant policy within the CMS

to assign roles, configure users, workstations, etc. and perform sensitive system maintenance that

most users should not have the permission to perform. The administrator should also ensure that

the database and files associated with the CMS are properly backed up per plant IT guidelines.


There are many events that can have a negative effect on plant performance, and some that represent

serious safety hazards. Reliable automation control logic can be compromised by the following events:

• Human Error

• Equipment failure

• Sabotage

• Power surges / interruptions

• Fire

A CMS offers the following protections from these events:

• Human Error: If someone makes changes to a program that result in undesired performance, or

corrupts the program due to inadvertent changes, the prior version of the program is readily


• Equipment failure: Equipment can and does fail. If the hardware fails and the only good copy of

the program logic was in that hardware, the plant has a problem. With a CMS, the hardware is

replaced and maintenance personnel download the latest version of the program to the processor

resulting in only a few minutes of downtime.

• Sabotage: As unfortunate as this threat is, someone can connect directly to many devices

(especially those in remote, unsecured locations) and modify the program with harmful results. A

CMS is designed to store processor passwords (in the case of some processors), so these are not

available without going through the CMS. Also, the CMS will periodically upload the logic from the

processor for comparison with a copy on file. Changes can be identified in graphical detail, and

immediate notification can be sent to responsible individuals.



Safeguarding your Plant Automation with Change Management

• Power surges / interruptions: Power issues can cause equipment to lock up or go off-line. If these

situations result in a loss of the program, it can be downloaded from the CMS after the hardware is


• Fire: Any fire will be a major disruption. Whether a single device or an entire facility is lost, having

all program logic stored in a central, organized CMS repository accelerates the time and decreases

the cost associated with resuming production. Insurance

underwriters are beginning to factor in the use of a Change

Management System in assessing the risk profile of


Without proper system safeguards these events can lead to

increased downtime and an increase in “mean time to repair”

(MTTR). Recovering from these events quickly requires adequate

planning on the hardware and maintenance strategy, and a

reliable and recent backup of the automation control program

logic. Current and complete backup copies of the program logic

require the features of a CMS. While a manual backup approach

may appear adequate at first glance, experience has shown that

plant personnel have too many tasks that compete for the time

to manually back up programs on a consistent basis. Also, the

increased visibility of changes through better reporting and the

potential for process improvement brought about by the

effective use of a CMS application can quickly pay for the CMS.

Insurance Underwriters are

beginning to factor in the use

of a Change Management

System in assessing the risk

profile of facilities.


What types of device programs should be put under the management of a CMS? The types of devices

to be maintained by a CMS will vary from manufacturing facility to manufacturing facility, and each of

these device types has a wide variety of manufacturers, network configurations, models, support

software, and versions of support software. To properly manage these programs and devices, all these

factors have to be understood. The most common devices are defined below, along with any unique

considerations from a CMS perspective.

PLCs – Programmable Logic Controllers. This is the most common type of device supported by a CMS.

There are a significant number of PLC vendors and each has a proprietary software package for PLC

program editing. A CMS application should be able to interact with all of the major brands of PLC editor

software to capture and detect changes, and provide an alternate method of capturing the project files



Safeguarding your Plant Automation with Change Management

on the editor workstation in the case of legacy or non-standard devices. A newer variant of the PLC,

called the Programmable Automation Controller (PAC) performs the same tasks along with some

expanded capacity for managing multiple applications simultaneously.

CNCs - Computer Numerical Controllers. The CMS will need to access the control ladder, part programs,

and process parameters as part of the backup process. These can be located in standard locations as

defined by the manufacturer, or they can be located in custom locations as developed by the OEM.

Secondly, file locations can be different based on types of CNCs within a model. For example, a single or

dual axis CNC within the same model can have different file locations. Prior to the installation of a CMS

these factors should be defined and documented. Company standards for OEM code design can greatly

standardize the logic designs and reduce CMS costs for supporting CNC devices.

Robots – Most robots that have FTP communications are straightforward

for change management. The robot manufacturer or plant controls group

should provide the file list for each type of robot.

HMI – Human Machine Interface. CMS applications typically provide

integrated support for commonly used HMI packages. If an HMI is used

that the CMS does not have a unique driver for, a generic module that backs

up the PC workstation development environment files can be used.

A CMS application

should be able to

interact with all

major brands of

device editor

software to capture

and detect changes.

PC Controls – These types of devices are typically used in machining

operations. These are PCs that are running a control program that mimics

the operation of a PLC. Some of these differ slightly from the PLC

programming software they are emulating; others are custom applications.

In all cases careful consideration to device communications and

understanding the PC Control file structure is required for a successful CMS

installation. Typically, a unique driver or a generic module that backs up the

development environment files can be used.

Welders, Drives, and Misc. PC Control Applications – These can be

supported by a generic module that provides support for general PC

applications and files.

Word, Excel, AutoCAD, and general Windows files - These can be supported by a generic module that

provides support for general PC applications and files or specialized drivers for these applications that

address document management.



Safeguarding your Plant Automation with Change Management


The selection of the best CMS application to meet a facility’s needs requires a careful assessment of

the features provided by a CMS and the plant’s requirements. The features outlined earlier are expanded

here to explore various approaches used by CMS users.

• Backup Archive: Many facilities will set retention parameters to maintain a representative number

of prior versions of program files. These parameters will include the number of copies to maintain

and a minimum age of a copy to be deleted. The age requirement is very useful when multiple

unsuccessful attempts are made to correct a program issue and it is determined that reverting to

an older copy of the program would be a better starting point than recent edited versions.

Change detection: Optimal CMS benefit is achieved when users go through the CMS to make all

program changes. This ensures a complete history of changes. When this is not achievable for

various technical or political reasons, the CMS should have the ability to interrogate devices and

compare the program running in the device to a reference copy in the CMS. If changes are

detected, appropriate identification and notification should occur.

Change documentation: As program editor software packages vary in their capability to identify

changes, the CMS yields tremendous benefit by providing a consistent, intuitive tool to compare

changes between any two versions of a program. This could be between a master copy, prior

version or the current version in the processor.

• Historical tracking: It is of significant use when assessing areas for process improvement to be

able to identify the frequency and type of changes to each device against its device type,

production line and those individuals making the changes. When norms are identified it is

straightforward to identify devices that are experiencing excessive changes and aid in identifying

root causes.

• Secured user and workstation access: Each user should be authenticated by the CMS. In addition,

some facilities have line-of-sight restrictions on which workstations can be used to edit certain

device programs. This is often utilized when improper program changes could have safety


• Controlled editor operations: Users should be assigned to groups with permission profiles that

map to the user’s authority within the plant. Careful consideration of these roles during

implementation is encouraged. It is also advisable to keep the role structure as simple as possible.



Safeguarding your Plant Automation with Change Management

• Disaster recovery: If the device hardware fails a replacement device will need to be obtained and

connected to the network. A CMS user will then download the latest copy of the program to the

device to resume operation.

Change notification: Notification of change is an important benefit of the CMS, though users will

often establish filters on the types of changes they wish to be alerted to.

• Non-networked device management: Disconnected devices can be supported by a checkout and

check-in procedure, or if provided by the CMS application, non-networked tools can be used to

download copies of programs from the central repository in order to provide the controls engineer

access to the programs remotely. It is also helpful if the CMS can compare the program in the

device with the one downloaded from the repository, capture user comments regarding program

changes, assist in creating new programs in the field, and synchronize all changes back to



The selection of a Commercial Off the Shelf (COTS) product that supports a wide variety of hardware

and software control types will reduce the cost of implementation, and life cycle costs while providing

the company with flexibility in its controls strategy. A COTS software product (vs. a toolkit with features

and scripts) will have an implementation scope that is similar to other plant-wide software


The major components of implementation are:

• Pre-Installation tasks: These include gathering the stakeholders for kick-off meeting, identification

of the plant and vendor team members and their responsibilities, documenting project milestones,

gathering a significant amount of information about the devices and programs in the plant, and

agreeing on a hierarchy for program storage.

• Software installation on the server and associated support workstations: This involves the

identification of the computers to be used by the CMS.

• Identification of the device communication routes: The CMS will need to communicate with

devices in a similar manner to plant personnel.

• Configuration of these communication routes for the various managed devices: Once the routes

are established, the ‘best’ routes will be established for various devices.



Safeguarding your Plant Automation with Change Management

• Configuration of the devices to be supported: The CMS is populated with copies of recent

program files for each project.

• Documentation of the As-

Configured topology: This

documentation will be an

invaluable guide as new plant

personnel are involved in

maintaining the CMS over its


A key element to maximizing

the value of the CMS is properly

education the users on the

value to be derived from the


• User education: A key element to maximizing the value of the CMS is properly educating the users

on the value to be derived from the system and its proper usage. Training sessions teach users at

various levels of system privilege how the CMS works, what their responsibilities are, and how to

properly maintain the various elements of the system. Often when users see the detailed change

identification that a CMS provides, there is little resistance to the change in work practice to use

the system.

• Acceptance and signoff: A clear set of milestones documented at the beginning of the project will

ensure that all parties properly meet expectations.


A facility must consider its current and future needs to properly evaluate of the product offerings

in the marketplace. While several products exist in the marketplace, once the device support

requirements are identified, there are typically only a few product offerings that are well suited to

meet the plant’s needs. The option of using multiple independent Point Solutions is discussed

along with some criteria for evaluating a single plant-wide CMS solution.

Point Solutions

While some controls vendors offer basic version control within their packages, there are several

disadvantages to these point solutions. The reliance on these individual packages for program

backup versus using a plant-wide CMS has a number of limitations, including:

• Backups and program revisions are located in multiple, inconsistent locations

• Only selected systems are backed up

• Inadequate security and access controls are in place to ensure programs are not lost



Safeguarding your Plant Automation with Change Management

• The IT department will not be able to manage file backups in an orderly fashion, and a single

hard drive failure could result in the loss of all backups.

Plant-wide CMS Criteria

• An ideal CMS solution should meet the following criteria:

• A proven package that provides strong support for current and many legacy applications.

• Support for most common controls technologies with little or no on-site coding

• Ability to tailor and expand the CMS to meet unique plant needs

• Support for generic file structures, documents, images, etc.

• Backing by a vendor that prioritizes the CMS as a key product in its portfolio, along with

sufficient market presence, history and breadth of offering.

• Flexible architecture to allow controls technologies to be added or removed over the life of

the system without re-implementation. This will offer the user flexibility in their controls


• Solid product support and upgrades


The regulatory environment under which a facility is governed can have a number of impacts on the

operational configuration of a CMS as well as the requisite features. Two of the more common US

Government regulations that impact plant operation are electronic signatures (commonly referred to by

the section of the US Code of Federal Regulations dealing with the usage of electronic signatures –

21CFR11) and the Sarbanes-Oxley Act of 2002.

The use of electronic signatures and workflow processes to replace manual paper-driven controls

continues to gain momentum in pharmaceutical environments. These tools can significantly streamline

the process of making changes in a validated environment and help to ensure that proper changes

processes are followed. A CMS with electronic signature and workflow capability can route proposed

changes to appropriate personnel, manage the use of the proposed change during testing phases so

that produced product is appropriately quarantined, and capture approval of the change for use in

production. The CMS also produces audit logs for use in regulatory reporting.

Many other facilities can utilize the electronic signature and workflow features of a CMS on a subset of

their automation where sensitive operations are controlled. This would provide added security and



Safeguarding your Plant Automation with Change Management

review of changes prior to implementation in devices controlling mixture, temperature or other critical


The impact of Sarbanes-Oxley on operational reporting at the plant level continues to evolve. Accurate

financial information from each facility is necessary to satisfy corporate reporting requirements, and

Section 404 of the regulation speaks to the role of IT controls in this reporting. An automation CMS is a

contributing a tool to strengthen the confidence in plant production data through greater assurance of

product merchantability.


With clear requirements, sponsorship from corporate and plant management, careful product selection

and focused implementation, a Change Management System will deliver tremendous value. Rapid

recovery from device failures, secure access to program history, compliance with corporate and

regulatory policies, and process improvement are all among the benefits of a CMS solution.



One CMS application that is widely

used complex automation

environments worldwide is

AutoSave. This product, from

AVUSEY-MDT, is a full-featured

change management solution

providing a comprehensive suite of

tools to protect, save, restore,

discover, and track changes for

industrial programmable devices

and documents. Many of the world's

largest users of automation rely on

the AutoSave software suite to

effectively control program versions and minimize downtime of plant floor automation by supporting

the most comprehensive range of devices and editors in the industry from Schneider, Siemens,

Mitsubishi, Indramat, GE, Rockwell Automation and many others.



Safeguarding your Plant Automation with Change Management


Another widely used CMS application is versiondog. versiondog analyzes the automation device

and system programming running across the plant floor using automated backup and compare

functions to monitor, track and store changes. This synchronization between versiondog and

plant systems enables the distribution and monitoring of company-wide technical standards and

provides greater control, security and visibility into understanding the who, what, when, where and

why of changes to automation devices and systems involved in manufacturing processes.


(1) Georgetown University (n.d.) Data Warehouse: Glossary


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