The RDS-PP reference designation system

Reference designation is a highly modern, future-oriented method of plant classification. The RDS-PP provides the basis for object-oriented identification of the individual plant components having any number of relations with other objects. The new classification system offers major advantages, especially, when applied in modern organization systems, e.g. plant management or maintenance systems. In the text below, the term “alphanumeric” is used to describe letter characters only.

 

Reference to codes and standards

The Reference Designation System for Power Plants is a standard-based system developed by VGB Power Tech for the identification of power plants. It is a further development of the power plant classification system (KKS), which is not specific to any particular language, power plant type, or field.

The main reason for developing the new system was to establish a connection to standards. The DIN standard 6779 entitled “Structuring principles for technical products and technical product documentation,” contains the most important general conditions for RDS-PP. Based on this series of standards, a standard DIN 6779-10 was developed especially for power plants in collaboration with VGB. The national standard was accepted by the ISO (International Organization for Standardization) in early 2008 and published as an international standard under the name ISO/TS 16952-10. The IEC (International Electrotechnical Commission) had already published the international series of standards IEC 61346 on the structuring principles and reference designations of industrial systems, installations and equipment and industrial products. To unify the standards for reference designation, the organizations have agreed on a future generic series of standards with the name DIN EN 81346. Moreover, the standard Reference Designation System for Power Plants (RDS-PP) includes rules for the reference designation of signals (IEC 61175), for identification of terminals (IEC 61666), and for the classification and identification of documents (IEC 61355). With its reference to these international series of standards, the RDS-PP is an internationally recognized standard for identifying power plants.

Guideline B101 and application explanations B116 developed by the working panels of the VGB are also part of the RDS-PP code. They contain the code letters for the system classification for power plants and assistance and examples for applying the classification system.

normen eng

 

General description

The main tasks of a classification system for power plants are:

  • Unequivocal identification of technical objects and documents.
  • Classification according to purpose, task, and composition.
  • Representation of the technical structures.
  • Representation of networked relationships.

The basic structuring principles include three different aspects for structuring the various plants. In this context, it is important to clarify three important questions for each individual object:

  • Which function possesses or manipulates the object? (functional)
  • Where is the object located? (location-oriented)
  • What type of object is it? (product-oriented)

In a plant identified according to RDS-PP, four different but interrelated structure trees therefore result. The function, the product, and the location of technical objects are the structure trees already known. The reference designation system also has a further tree for structuring functional relations. With the “functional allocation,” the RDS-PP is also able to establish a connection between two functions. The shared aspects of the structures or relationships between the different trees are termed role relations.

strukturBaum eng

These relationships between the different aspects of a designated object being considered are the core of the reference designation system. They can provide information about the components in the various types of document and products involved in the system. In addition to the reference designation according to function, location, and product aspects, according to ISO/TS 16952-1 the RDS-PP also contains a specific designation for signals, terminals, and documents, which is derived from the function of the object and a higher-level conjoint designation. The identifier of an object to be identified can therefore consist of maximum three different parts: the conjoint designation, the reference designation, and a specific designation. The identifier can be composed of different combinations of these three components, which are shown in the following table.

Conjoint designation

 

 

Conjoint designation

Reference designation

 

Conjoint designation

Reference designation

Specific designation

Conjoint designation

 

Specific designation

 

Reference designation

 

 

Reference designation

Specific designation

 

Each of the three sections of the identifier can consist of one or more so-called designation blocks with different structures. A designation block is subdivided into different levels that contain different combinations of letters and numerals. The smallest unit of information of the reference designation are the data characters. These are grouped together into alphanumeric and numeric sections at the relevant levels.

identifikator eng

The individual blocks can be identified by a defined prefix character. The following table shows the various designation blocks with the relevant prefixes and sources. Different designation blocks can also be combined. The rightmost prefix always determines the aspect of the entire reference designation.

Prefix

Designation

Designation tasks / aspects

Prefix origin, basic principles specified in

#

Number

Conjoint designation

ISO/TS 16952-1

=

Equals

Function-oriented designation

IEC 61346-1

==

Equals-Equals

Functional allocation

ISO/TS 16952-1

+

Plus

Point of installation

IEC 61346-1

++

Plus-Plus

Location

ISO/TS 16952-1

-

Minus

Product-oriented designation

IEC 61346-1

:

Colon

Terminal designation

IEC 61666

;

Semicolon

Signal designation

IEC 61175

&

And

Document designation

IEC 61355


Conjoint designation

For the “conjoint designation” section, RDS-PP provides a designation block of the same name with a fixed structure.

 For the “conjoint designation”, ISO TS 16952-10 provides two levels separated by a period, each with up to twelve alphanumeric or numeric data characters. The block therefore makes it possible to differentiate, for example, different locations or control centers having common aspects. The designation block is introduced by the “hash sign.” The “conjoint designation” is an independent block because it is neither aspect-oriented nor assignable to the specific designation. For this reason, it provides a separate section.

 

Breakdown level

 

1

 

3

Section

 

1....4

 

5

Data character

#

A….N

.

A….N

Example

#

KW01

.

E10


Reference designation

The “reference designation” section has the task of identifying the object to be described according to the already stated three different aspects: function, location, and type. In total, there are five different types of designation block.

The first type is called the “function block.” It is one of two function-oriented designation blocks. It structures the technical objects of a plant from the viewpoint of the task and purpose of the components. This designation block consists of three different breakdown levels. For the higher-level distinction, a maximum of one alphanumeric and two numeric data characters are available at breakdown level zero. The other two breakdown levels each consist of combinations of five with three or two alphanumeric and two or three numeric data characters. The classification of the alphanumeric data characters is defined at breakdown level one by the VGB code B101 and at breakdown level two by the IEC/PAS 62400.

Breakdown level

 

0

1

2

Section

 

0

1

2

3

4

Data character

=

AN(N)

AAA

NN

AA

NNN

Example

=

D0

LAC

10

GP

010

 

The second function-oriented type of designation is the “functional allocation.” It has the task of grouping together technical facilities of different types under a common function. As an example, the mechanical parts of a pump and its electrical controls are assigned to the same function. A distinction is made between two types of functional assignment. The group level is for identifying function areas and function groups. It only comprises the system designation with breakdown levels zero and one. Technical facilities are more specifically functionally grouped at the individual level. This designation block consists of all three breakdown levels. Both at the group level and at the individual level, a third breakdown level can be appended, separated by a period. It represents an I&C function for the functional allocation. In this block, too, the classification of the alphanumeric data characters of breakdown levels one, two, and three must be made by the defined code B101 and ICE/PAS 62400.

Breakdown level

 

0

1

2

 

3

Section

 

 

1

2

3

4

 

5

Data character

==

AN(N)

AAA

NN

AA

NNN

.

AANN

Example

==

D0

MKV

10

GA

010

.

AA01

Code letter

Designation

AA

Signaling, monitoring

CA

Individual closed-loop control

CB

Pilot control

HA

Operation control and monitoring

MA

Direct measurement

MB

Measured quantity calculation

SA

Individual open-loop control

SB

Group control

ZA

Equipment unit protection

ZB

Plant protection

 

To identify the product aspects or the type of an object, the reference designation system includes the “product designation.” It groups together all objects of one type and establishes the connection to the manufacturer or supplier by the product reference. The simple “product designation” for acquiring devices and modules contains two alphanumeric and up to three numeric data characters. In this case, the classification is made according to the IEC PAS 62400 standard only. The product-oriented designation is preceded by a “minus”sign. In the identification of the constituent parts of a “product,” the “nested product designation” can be used. It permits multiple designation blocks to be concatenated, the prefix only having to be written in front of the first block. The combination of the designation blocks “function” and “product” is called “component designation.” It is therefore possible to move from the function aspect to the product aspect.

Breakdown level

 

1

2

Section

 

1

2

3

4

Data character

-

AA

(N)NN

AA

(N)NN

Example

-

MA

01

XD

02

 

For identification from the location aspect, the RDS-PP contains the point of installation and location designations. Both have very similar structures. The “point of installation” designation block describes the physical location of a technical object with respect to its task. The code of the RDS-PP reference designation system makes a distinction between the following tasks:

  • Point of installation in installation units of the electrical and I&C engineering,
  • System-oriented installation units of the electrical and I&C engineering,
  • Location-oriented installation units of the electrical and I&C engineering,
  • Points of installation in mechanical and civil engineering equipment

The “point of installation designation” contains the whole or parts of the designation of the “function block.” Depending on which task it is assigned to, the “point of installation” can have up to three or four breakdown levels. It is also possible to relate the “points of installation” to their “location.” This can be done by taking over the first breakdown level of the “location block.”

Breakdown level

 

0

1

2

 

3

Section

 

 

1

2

3

4

 

5

Data character

+

AN(N)

AAA

NN

AA

NNN

.

A../..N

Example

+

D0

LAC

10

GP

010

.

Outlet

 

The system-oriented and location-oriented installation units of the electrical engineering and I&C and the “points of installation” of the mechanical engineering and civil engineering have the structure shown in the table below. In the case of “points of installation” in installation units of the electrical engineering and I&C, the second breakdown level can be omitted. In that case, only the system level (breakdown level one) of the “function designation” is taken over. Breakdown level three can contain up to twelve freely selectable data characters. The “point of installation” identification is recognizable by a preceding “plus” sign.

The reference designation of the “location” has the same structure as the “point of installation” in installation units of the electrical and I&C engineering. It has the task of describing locations. Takeover of the “function reference designation” establishes the building reference of the technical equipment.

Breakdown level

 

0

1

 

3

Section

 

0

1

2

 

5

Data characters

++

AN(N)

AAA

NN

.

A../..N

Example

++

D0

ULA

10

.

R 010


Specific designation

Alongside the function-oriented, product-oriented, and location-oriented designations, the specific designations are an important function in application of the RDS-PP. They permit unequivocal identification of signals, terminals, and documents.

Combined with the “function” reference designation, the “signal” block provides unequivocal signal identification.

Breakdown level

 

1

 

3

Section

 

1

2

3

5

Data character

;

AA

NNN

.

A.....N

Example

;

XQ

001

.

 

 

The individual signals are classified according to IEC 61175. The first data character of breakdown level one distinguishes between the main classes signal origin (code letter: X) and signal application (code letter: Y). Both the subclasses and the count numbers of the signal classes are defined in the power-plant-specific standard ISO/TS 16952-10. The prefix for the identification of signals is a “semicolon.”

Similarly to the signals, the identification of terminals of technical objects is composed of a reference designation and a “terminal designation.” In classification of the terminals, it is possible to use the existing “terminal identifiers” of the “components.” In “components” without designated terminals, the code letters can be taken from the standards for the mechanical engineering and electrical engineering. Unlike the other designation blocks, the sections of the terminal designation can contain lowercase letters and special characters.

Breakdown level

 

1

 

3

Section

 

1

 

5

Data character

:

A../..N

.

A../..N

Example

:

PE1

.

 

 

The identification of documents is implemented in the RDS-PP with a combination of three different designation blocks.

dokuKZ eng

The object designation usually consists of the “function block.” In this case, the depth of the structure can be decided by the user. Depending on the document, it is possible to use only the system level or the entire “component designation” as the object designation. The generally valid DCC (document class code) of the series of standards DIN EN 61355 is used to identify the document type. It both defines the code letters and contains the various numbering specifications. The last part of the “document designation” is used for counting different pages of a document.


Applying the designation system

According to the ways of combining the individual sections of an indicator stated above, various concatenations and assignments of the individual designation blocks result. Concatenating one or more blocks always results in a new unique designation with a defined aspect. The following table summarizes all permissible concatenations of the classification system.

Concatenations of designation blocks

= Function

- Product

 

= Function

- Product

: Terminal

= Function

- Product

& Document class

= Function

; Signal name

 

= Function

& Document class

 

== Functional allocation

; Signal name

 

== Functional allocation

& Document class

 

+ Point of installation

& Document class

 

++ Location

& Document class

 

 

The core of this new type of reference designation system are the interrelations between the individual designation blocks. In this way, both one-to-one identification of the technical objects according to various aspects and referencing the designations to designation blocks that have been identified in another aspect are possible. This facility gives the reference designation system an object-oriented character, unlike its predecessors, which provides a big advantage when used in organization systems. In this context, assignment refers to the role relations between the unique designations of different aspects.

In application of the reference designation system RDS-PP, the VGB guideline B101 and DIN 6779-2 or DIN ISO TS 16952-2 are the most important codes and standards. B101 was elaborated by a working panel of the VGB and contains the letter code of breakdown level one for the designation blocks “function”, “functional allocation,” “point of installation,” and “location.” In the so-called system key, the letter combinations consisting of three letters are defined with all the systems and system boundaries of a power plant.

Because the B101 guideline is based on a classification scheme for infrastructure objects (DIN EN 81346-2), this standard has a standardizing character. Breakdown level two in blocks “function,” “functional allocation,” “location,” and “point of installation”, or both breakdown levels of the “product designation” are defined in national and international standards (national: DIN 6779-2; international: ISO TS 16952-2). As an aid to correct application of RDS-PP in practice, in December 2007 the VGB working panel published a collection of application explanations (VGB-B116). It contains various application scenarios and solutions for the identification of systems in power plants.