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BS 6556-2:1985

Current
Current

The latest, up-to-date edition.

Low speed digital signals for use in coal mines Specification for transformer coupling
Available format(s)

Hardcopy , PDF

Language(s)

English

Published date

31-01-1985

Foreword
Committees responsible
Specification
1 Scope
2 Definitions
3 General conventions
4 Data link configurations
5 Channel allocation
6 Data rate
7 Modulation parameters
8 Line spectrum
9 Modulator
10 Demodulator
11 System performance
12 Cable connections
13 Environment
14 Line circuit parameters
15 Marking
Appendix
A Cable parameters used for system performance test
Tables
1 Manner of modulator operation
2 Manner of demodulator operation
3 Performance tests
Figures
1 Simplex operation
2 Duplex point-to-point operation
3 Multi-drop operation
4 Resistive node
5 Frequency shift keying (FSK)
6 Originate channel spectrum limits
7 Answer channel spectrum limits
8 Modulator configuration
9 Demodulator configuration
10 Performance test configuration
11 Generator of 511 bit pseudo-random data
12 Core configuration of cable

Defines electrical input and output characteristics of intrinsically safe transmitting and receiving circuits forming a low speed digital data transmission link in which data is transmitted using frequency shift keying techniques

This Part of BS 6556 specifies the electrical input and output characteristics for the transformer coupling of intrinsically safe transmitting and receiving circuits for use in coal mines. These form a low speed digital data transmission link in which data is transmitted using frequency shift keying techniques.

A data transmission system comprises a master and up to 15 physical slaves. The circuits of all stations are galvanically isolated from the line circuits by transformers.

NOTE 1 Each physical slave may support more than one addressable logical slave as specified in Part 3 of this standard up to a maximum of 15 addressable slaves for the complete system.

This Part of BS 6556 only applies to apparatus where the circuits connected to the transmission lines are designed to be intrinsically safe in accordance with BS 1259, BS 5501-7 or BS 5501-9 as appropriate.

NOTE 2 Where apparatus, which is intended to be used in potentially explosive atmospheres, contains other circuits which are not intrinsically safe, those circuits will have to be given an alternative form of protection in accordance with BS 229, BS 4683 or BS 5501 as appropriate.

NOTE 3 The titles of the publications referred to in this standard are listed on the inside back cover.

Committee
W/-
DevelopmentNote
Supersedes 82/76935 DC, 88/70377 DC and 90/81014 DC (09/2005) Reviewed and confirmed by BSI, January 2011. (12/2010)
DocumentType
Standard
Pages
22
PublisherName
British Standards Institution
Status
Current
Supersedes

BS 6556-3:1985 Low speed digital signals for use in coal mines Specification for message protocols
BS 6704:1996 Code of practice for selection, installation and maintenance of intrinsically safe electrical equipment in coal mines
BS 6556-1:1985 Low speed digital signals for use in coal mines. Specification for optical coupling

BS 4683-3:1972 Specification for electrical apparatus for explosive atmospheres Type of protection N
BS 6556-1:1985 Low speed digital signals for use in coal mines. Specification for optical coupling
BS 5754:1980 Specification for electrical analogue and state signals for use in coal mines
BS 5501-9:1982 Electrical apparatus for potentially explosive atmospheres Specification for intrinsically safe electrical systems \'i\'
BS 5501-7:1977 Electrical apparatus for potentially explosive atmospheres Intrinsic safety \'i\'
BS 4683-1:1971 Specification for electrical apparatus for explosive atmospheres Classification of maximum surface temperatures
BS 1442:1969 Specification for galvanized mild steel wire for armouring cables
BS 4683-2:1971 Specification for electrical apparatus for explosive atmospheres The construction and testing of flameproof enclosures of electrical apparatus
BS 6556-3:1985 Low speed digital signals for use in coal mines Specification for message protocols

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