(19)

(11)

EP 0 500 631 A1

(12)

(43) Date of publication: 02.09.1992 Bulletin 1992/36 (21) Application number: 90916353.0 (22) Date of filing: 13.11.1990

(51) International Patent Classification (IPC):  G01L 1/ 22( . ) G05F 1/ 46( . ) G05F 1/ 567( . ) G05F 1/ 10( . ) G05F 1/ 56( . ) (86) International application number: PCT/GB1990/001744 (87) International publication number: WO 1991/007713 (30.05.1991 Gazette 1991/12)

(84) Designated Contracting States: DE FR GB IT SE (30) Priority: 13.11.1989 GB 19890025578 26.07.1990 GB 19900016434 10.08.1990 GB 19900017573 (71) Applicant: BRITISH TECHNOLOGY GROUP LTD London SE1 6BU (GB)	(72) Inventor: BINNS, John, Philip, Lincoln Cuckfield West Sussex RH17 5LR (GB) (74) Representative: Gaskin, John Shield, et al  Patents Department British Technology Group Ltd 101 Newington Causeway London SE1 6BU London SE1 6BU (GB)