(19)
(11) EP 0 470 558 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
27.05.1992 Bulletin 1992/22

(43) Date of publication A2:
12.02.1992 Bulletin 1992/07

(21) Application number: 91113143.1

(22) Date of filing: 05.08.1991
(51) International Patent Classification (IPC)5G08C 19/46
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 06.08.1990 US 583480

(71) Applicant: CINCINNATI MILACRON INC.
Cincinnati Ohio 45209 (US)

(72) Inventors:
  • Morser, Harold, A.
    Cincinnati, Ohio 45243 (US)
  • Nead, Thomas, E.
    Loveland, Ohio 45140 (US)

(74) Representative: Lally, William et al
FORRESTER & BOEHMERT Franz-Joseph-Strasse 38
80801 München
80801 München (DE)


(56) References cited: : 
   
       


    (54) Apparatus for position measurement


    (57) Interface circuits for electromagnetic position transducers are provided to reduce the effects of capacitive coupling occurring in the conductive cabling between the position transducers and the associated interfaces located remotely therefrom. Capacitive coupling of excitation signals to the transducer output signals result in error signals appearing as cyclic error in measured positions. The magnitude of the coupled signals are substantially reduced by providing excitation signals symmetrical with respect to ground. The magnitude of the coupled signals are also reduced by presenting equal impedances relative to ground to the output signal return and signal paths. By reducing the effects of capacitively coupled signals, conducting cables for the excitation signals and the transducer output signals may be incorporated in a single shielded cable.





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