CERN
LHC Project Document No.
LHC-C-QA-0001 rev 1.0
CH-1211 Geneva 23
Switzerland
CERN Div./Group or Supplier/Contractor Document No.
AB - CO
the
EDMS Document No.
Large
Hadron
Collider
473086
project
Date: 2004-07-26
Quality Assurance Definition
BASIC SYNTACTIC RULES
FOR NAMING OF LHC ENTITIES
AND THEIR PARAMETERS FOR THE
CERN CONTROL CENTRE
Abstract
This document defines the rules for the syntax of the names given to LHC entities and
for settings and observables of these LHC entities accessible through the control
system, and visible in the CERN Control Centre. The naming of these objects as defined
by experts or users must obey the basic syntactic rules as described in this document.
Prepared by :
Checked by :
Approval Leader :
Ronny Billen
AB/CO
[email protected]
Robin Lauckner
Pascal Le Roux
Maciej Peryt
Chris Roderick
Josi Schinzel
Markus Zerlauth
Robin Lauckner
AB/CO
Roberto Saban
TS/HDO
Approval List
M. Albert, R. Bailey, S. Baird, C. Balle, M. Batz, A. Bland, O. Bruning, E. Carlier,
E. Ciapala, P. Charrue, S. Chemli, P. Collier, K. Cornelis, Ch. Delamare, R. Denz,
F. Di Maio, L. Ducimetiere, U. Epting, B. Frammery, P. Gayet, B. Goddard, J-J. Gras,
J-C. Guillaume, E. Hatziangeli, W. Heinze, A. Hilaire, W. Hofle, R. Jones, Q. King,
M. Lamont, I. Laugier, D. Manglunki, E. Manola-Poggioli, R. Martini, H. Milcent,
P. Ninin, T. Pettersson, R. Schmidt, L. Serio, C-H. Sicard, P. Sollander, H. Thiesen,
M. Tyrrell, M. Vanden Eynden, J. Wenninger, D. Widegren
LHC Project Document No.
LHC-C-QA-0001 rev 1.0
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History of Changes
Rev. No.
Date
Pages
0.1
05-Mar-2004
All
First draft version for discussion internally in AB/CO/DM
0.2
12-Mar-2004
All
With input from R. Lauckner and AB/CO/DM
0.3
30-Mar-2004
All
Cleaned of for coherency with naming semantics
0.4
30-Apr-2004
All
After input from LHC-OP, ready for LHC baseline approval
15-May-2004
All
Submission for approval
23-Jun-2004
All
All relevant comments integrated
07-Jul-2004
6
26-Jul-2004
All
1.0
Description of Changes
Additional note on usage of asterisk and dollar sign in TS
Released version
LHC Project Document No.
LHC-C-QA-0001 rev 1.0
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Table of Contents
1.
PURPOSE .................................................................................................4
2.
SCOPE .....................................................................................................4
3.
POLICY ....................................................................................................4
4.
RESPONSIBILITIES .................................................................................4
5.
5.1
5.2
5.3
5.4
5.5
5.6
SYNTACTIC RULES...................................................................................5
ALPHABETIC CHARACTERS ......................................................................5
DIGITS .................................................................................................5
ALLOWED SPECIAL CHARACTERS .............................................................5
PROHIBITED SPECIAL CHARACTERS..........................................................6
CHARACTER SEQUENCE ..........................................................................6
EXAMPLES .............................................................................................7
6.
6.1
6.2
6.3
6.4
6.5
6.6
CONSIDERATIONS ON THE USE OF SPECIAL CHARACTERS ......................7
USE OF THE NUMBER SIGN......................................................................8
USE OF THE HYPHEN...............................................................................8
USE OF THE FULL STOP ...........................................................................8
USE OF THE SOLIDUS .............................................................................8
USE OF THE COLON ................................................................................8
USE OF THE UNDERSCORE ......................................................................8
7.
RELATED DOCUMENTATION.....................................................................9
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1. PURPOSE
This document defines the basic syntactic rules for LHC entities, as well as for
their parameters, i.e. settings and observables. A setting is a piece of
information that needs to be sent to the equipment, while the observable is a piece of
information that can be read from the equipment. For the ease of reading throughout
this document, the general term object will be used to denote the LHC entities, their
settings and their observables.
The purpose of this document is to give the formal rules for the use, order and
arrangement of symbols forming the name of these objects.
This document is one of the two documents that provide the rules for naming LHC
entities and parameters accessible through the control system. The other document
[1] defines the semantic of the name of the objects, i.e. the meaning of the symbols
within the name.
2. SCOPE
The syntax described in this document shall be used when defining names for LHC
entities and their parameters that are passed through the LHC controls system and its
subsystems such as:
ƒ
The LHC Logging System
ƒ
The LHC Alarms System
ƒ
The LHC Post-Mortem System
ƒ
LHC Settings
ƒ
LHC Measurements
The scope includes parameters of physical and virtual LHC components and higherlevel parameters such as accelerator physics parameters.
3. POLICY
The general policy is that experts or users that define names for LHC entities and their
related parameters should follow both rules for syntax and semantics.
For LHC part identification, LHC components and equipment names in general, the
rules and guidelines have already been defined [2,3,4].
For specific LHC components such as the cryogenic instrumentation, naming
conventions have been published as well [5]. The document “Description of QPS
Signals in LHC” [6] goes as far as the parameters of QPS components.
With the future remote controls of the LHC machine in mind, a general policy aims for
a standardisation in names that are visible and accessible for control room operators
and a large number of end-users. This document addresses the syntax for names of
LHC entities and their parameters.
4. RESPONSIBILITIES
Project Engineers at CERN responsible for naming LHC entities and their parameters
shall be aware of the syntactic and semantic rules and apply them accordingly. They
are responsible for proposing the relevant attributes that must be endorsed by AB-CODM, who will also capture and manage this information.
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5. SYNTACTIC RULES
This chapter gives the allowed and prohibited characters for entity and parameter
names. All the referred characters are part of the US-ASCII character set [7] and the
ISO Latin 1 character set [8], and can be found on the standard American keyboard
commonly used at CERN.
For reasons of comprehension and classification, the character set is split up in
alphabetic characters, digits and special characters.
Note that the alphanumeric character set includes both alphabetic characters and
digits.
5.1 ALPHABETIC CHARACTERS
The use of all of the 26 Latin capital letters is allowed without exception, i.e. from ‘A’
to ‘Z’.
The use of any of the 26 Latin small letters is prohibited without exception, i.e. from
‘a’ to ‘z’.
This implies that the use of lowercase as well as the combination of uppercase and
lowercase is not allowed for parameter names, thus excluding any ambiguity.
5.2 DIGITS
The use of all 10 digits, expressed in the Arabic notation by one figure, is allowed
without exception, i.e. from ‘0’ to ‘9’.
5.3 ALLOWED SPECIAL CHARACTERS
In general, special characters within names are used as delimiters and have no
purpose semantically speaking. This is the exhaustive list of allowed special
characters:
Allowed special characters
#
NUMBER SIGN
-
HYPHEN
.
FULL STOP
/
SOLIDUS
:
COLON
_
UNDERSCORE
Some considerations with respect to the use of these allowed characters in different
controls software environments are given in chapter 6.
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5.4 PROHIBITED SPECIAL CHARACTERS
For completeness, the following list gives the special characters that are prohibited:
Prohibited special characters
SPACE
EXCLAMATION MARK
"
QUOTATION MARK
PERCENT SIGN
&
AMPERSAND
(
LEFT PARENTHESIS
)
RIGHT PARENTHESIS
+
PLUS SIGN
,
COMMA
!
$
DOLLAR SIGN
'
APOSTROPHE
(*)
(*)
%
*
ASTERISK
;
SEMICOLON
<
LESS-THAN SIGN
>
GREATER-THAN SIGN
?
QUESTION MARK
@
COMMERCIAL AT
[
LEFT SQUARE BRACKET
\
REVERSE SOLIDUS
]
RIGHT SQUARE BRACKET
^
CIRCUMFLEX ACCENT
{
LEFT CURLY BRACE
}
RIGHT CURLY BRACE
|
VERTICAL LINE
~
TILDE
`
GRAVE ACCENT
=
EQUALS SIGN
(*)
(*)
It has been noted that the dollar sign, the asterisk and the equals sign are used
consistently for names given to equipment managed by the Technical Services
department, namely in the MP5i asset management system and the câblothèque.
Nevertheless, the use of these special characters must be prohibited outside this
specific domain.
5.5 CHARACTER SEQUENCE
The order and arrangement of the characters that are used for an entity or parameter
name, i.e. the full character sequence, should respect the following syntactic rules:
Syntax <Full_sequence>
Maximum 40 characters
<Starting_sequence>0..7<Following_sequence>
Syntax <Starting_sequence>
Maximum 15 characters
<Alpha>1..14<Alphanumeric>
Syntax <Following_sequence>
Maximum 15 characters
<Special>1..14<Alphanumeric>
Syntax Component
Character
Allowed
<Alpha>
Single alphabetic character
{‘A’..‘Z’}
<Alphanumeric>
Single alphanumeric character
{‘A’..‘Z’} and {‘0’..‘9’)
<Special>
Single special character
{‘#’,‘-’, ‘.’ ‘/’ ‘:’ ‘_’}
In summary, it is mandatory that parameter names start with an alphabetic character
followed by at least one alphanumeric character. This starting character sequence may
be followed by up to seven following character sequences, each starting with a single
special character and followed by at least one alphanumeric character.
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The starting character sequence and the following sequences must not exceed 15
characters each.
The total character sequence for a parameter name must not exceed 40 characters.
These rules define the maximum numbers of characters and sequences. The actual
name that is given to an object must be governed by appropriate use of syntax,
semantics and common sense.
5.6 EXAMPLES
For illustration, the following names are valid since they obey all the syntactic rules:
ABC
DEFGH.1I
J2#KL3.4M-N/O5P_QR67
STUV.A89L1.W2:X_W_Z
As counter examples, the following names are invalid since they violate one of the
syntactic rules:
1A
(use of prohibited starting character)
B2!34
(use of prohibited special character)
C#DEF
(starting sequence too short)
G234567890HIJKLM
(starting sequence too long)
N2-
(following sequence too short)
OPQRS.1234567890ABCDE
(following sequence too long)
TU/1V/2W/3X/4Y/5Z/6A/7B/8C
(too many following sequences)
ABCDEFGHIJ.KLMNOPQRST_UVWXYZ:01234567890A
(full sequence too long)
6. CONSIDERATIONS ON THE USE OF SPECIAL CHARACTERS
When an object is baptised with a name in the accelerator environment, it is a
common practice to encode information within the name. The purpose of this practice
it that the expert or the end-user are able to decode the symbols in the name and
expand it to comprehensible, meaningful information.
For reasons of quality assurance, the documents on conventions for naming of
equipment give rules, guidelines and recommendations. In general, the use of
alphanumeric characters is intended to encode the semantic part (e.g. ‘M’ for magnet;
‘3’ for third occurrence). On the other hand, the special characters are used as
delimiters, separators or as filling characters without any further meaning whatsoever.
Since the names will be used throughout the controls environment, these special
characters may be interpreted depending on the specific software area in which they
are used, and some precaution needs to be taken. The obvious software areas in the
controls environment are:
ƒ
High level programming languages (Java, C/C++) used in the business layer
and presentation tier;
ƒ
Web deployment based on HTTP and making use of hypertext functionality in
the presentation tier;
ƒ
Programming languages in the PC-type front end computers (C/C++);
ƒ
Native programming languages in industrial PLC-type front end computers and
SCADA supervision systems;
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ƒ
SQL and PL/SQL in the Oracle data resource tier.
The following considerations may guide the user in the choice of the allowed special
characters:
6.1 USE OF THE NUMBER SIGN
The number sign ‘#’ is also known as hash or pound sign.
The use of the number sign has no obvious interference with the present controls
software environment.
The hash sign is not a very discrete symbol and its use in a parameter name could
reduce readability.
6.2 USE OF THE HYPHEN
The hyphen ‘-’ is also known as dash or minus sign.
A potential risk may occur when using in applications in which calculations are
performed and the symbol is interpreted as the minus operator.
6.3 USE OF THE FULL STOP
The full stop ‘.’ is also known as period or decimal point.
A potential risk may occur when using in applications in which calculations are
performed and the symbol is interpreted as a decimal point.
The dot is a discrete symbol and its use in a parameter name could improve
readability.
6.4 USE OF THE SOLIDUS
The solidus ‘/’ is also known as slash or forward slash.
A potential risk may occur when using in applications in which calculations are
performed and the symbol is interpreted as the divider operator.
In the operating system environment of any UNIX flavour, the forward slash is used as
delimiter between file directory levels. A potential risk may occur when using the
solidus in literals that are used at the operating system level.
6.5 USE OF THE COLON
The use of the colon ‘:’ has no obvious interference with the present controls software
environment.
6.6 USE OF THE UNDERSCORE
The underscore ‘_’ is also known as the low line character.
The underscore character appears in printed text and on the computer screen at the
same height as the underlining of the text. This may lead the reader into confusion
whether the underlined character is indeed an underscore or a blank space. By
default, hyperlinked text in Web based applications is underlined.
The underscore is the default single wildcard character in SQL queries.
For industrial PLCs (Programmable Logic Controllers), the underscore character is the
only allowed special character in the use of character string literals [9].
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7. RELATED DOCUMENTATION
[1]
LHC-C-QA-0002
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
LHC-PM-QA-206
LHC-PM-QA-610
LHC-PM-QA-204
LHC-QI-QA-0002
LHC-DQ-ES-0003
ASCII TABLE
ISO 8859-1
IEC 61131-3
Naming of LHC Entities and their Parameters for the CERN Control
Centre
LHC Part Identification
LHC Part Identifiers – Guidelines
Equipment Naming Conventions
Naming Conventions for Cryogenic Instrumentation
Description of QPS Signals in LHC
ASCII character table and description
ISO Latin 1 character set
PLC Standard - Programming Languages - providing the basis