High precision synchronized measured value acquisition

Patent metadata

Field	Value
Publication number	US-9077513-B2
Application number	US-201214125290-A
Country	US
Kind code	B2
Filing date	Jun 6, 2012
Priority date	Jun 10, 2011
Publication date	Jul 7, 2015
Grant date	Jul 7, 2015

Abstract

The invention relates to a method for wire bound, high precision, temporal synchronization of measured value acquisition in a measurement system designed as a space coordinate measurement apparatus having a plurality of measurement sub-units with signaling of a time for triggering the measured value acquisition by means of a trigger signal and with the respective acquisition and intermediate storage of a measured value in the measurement sub-unit at the time determined by the trigger signal. Each acquisition of the measured value is carried out in the measurement sub-units in a time quantified manner with a local timing signal of the measurement sub-unit. A phase synchronization of the local timing signals of the measurement sub-units is then carried out using a synchronization signal in order to ensure simultaneity of the acquisition of the measured value in the measurement sub-units with a temporal uncertainty which does not exceed a phase jitter of the synchronization, and which is in any case less than 90% of a period duration of the local timing signal.

First claim

What is claimed is:

1. A method for a line-based high precision temporal synchronization of measured value acquisitions in a spatial coordinate measuring machine comprising a plurality of spatially distributed measuring subunits, the method comprising:
signaling an instant for triggering the measured value acquisition using a trigger signal;
respectively acquiring and buffer-storing a measured value in the measuring subunit at the instant determined by the trigger signal, wherein the measured value is acquired in the measuring subunits in each case in a time-quantified manner with a local clock signal of the measuring subunit;
phase synchronizing of the local clock signals of the measuring subunits using a synchronization signal for ensuring simultaneity of acquiring the measured value in the measuring subunits with a temporal uncertainty less than 90% of a period duration of the local clock signal; and
providing the synchronization signal and a further signal as common signal via a common signal line.

2. The method as claimed in claim 1 , wherein the temporal uncertainty is less than half a period duration of the local clock signal.

3. The method as claimed in claim 1 , wherein the temporal uncertainty is in less than one fifth of the period duration.

4. The method as claimed in claim 1 , wherein:
the signaling is performed using a measuring probe; and
the acquiring is performed using position value sensors.

5. The method as claimed in claim 1 , wherein:
providing the synchronization signal and the further signal as common signal is performed using a modulation method in such a way that the corresponding components can be reconstructed from the common signal, wherein the modulation method is performed in the form of an FSK, PSK, ASK or QAM.

6. The method as claimed in claim 5 , wherein:
the modulation method is performed as a digital modulation method, in the form of a logical combination of the synchronization signal and the further signal.

7. The method as claimed in claim 5 , wherein:
providing the synchronization signal and the further signal as common signal is performed using a line coding by which the local clock signals can be synchronized, wherein the line coding is in the form of a Manchester code.

8. The method as claimed in claim 5 , wherein:
the synchronization signal and the trigger signal as the further signal are provided using a combined clock-trigger signal, wherein the combined clock-trigger signal is transmitted via the common signal line.

9. The method as claimed in claim 5 , further comprising providing the synchronization signal via a supply signal as the further signal by means of a supply-voltage-carrying line as combined clock-supply signal.

10. The method as claimed in claim 5 , further comprising providing the synchronization signal and a data signal as the further signal via a common signal line as a combined clock-data signal.

11. The method as claimed in claim 5 , further comprising providing the trigger signal to the measuring subunits as a synchronous trigger signal, wherein the trigger signal is time-quantized with the synchronized clock signal in a subunit as trigger unit and is provided to the measuring subunits as the synchronized trigger signal.

12. The method as claimed claim 5 , further comprising providing the trigger signal to the measuring subunits as an asynchronous trigger signal, which is time-quantized with the synchronized local clock signal in each case in the measuring subunits.

13. The method as claimed in claim 1 , wherein:
the synchronization of the respective local clock signal is performed using a feedback control loop from the synchronization signal, wherein the synchronization signal has a multiple of the cycle time of the local clock signal generated therefrom.

14. The method as claimed in claim 1 , wherein:
the local clock signal has a constant, freely selectable phase offset relative to the synchronization signal as latency time compensation for compensating for a signal propagation time on account of line lengths and circuitry delays on the basis of the signal propagation times and delays between the measuring subsystems that can be determined automatically by the measuring system.

15. The method as claimed in claim 14 , wherein:
the freely selectable phase offset is configured by the measuring system automatically.

16. The method as claimed in claim 1 , wherein:
the subunits with their synchronized local clock signals acquire the measured values and store a temporally limited history of the measured values;
signaling the instant of triggering is performed by distributing the trigger signal, which defines the trigger instant and is asynchronous with respect to the synchronized clock signals; and
the measured values are determined by computational interpolation or extrapolation of the synchronously acquired measured values to the asynchronous trigger instant, wherein:
wherein at least one of the subunits for the interpolation or extrapolation carries out a time determination with a temporal resolution below a period duration of the local clock signal.

17. A triggerable coordinate measuring system comprising a plurality of measuring subunits comprising:
a measured value input for acquiring a physical variable as measured value;
a line-based trigger signal input for triggering the measured value acquisition at an instant determined by a trigger signal;
a local clock signal for the time-quantified, measuring-subsystem-internal signal processing of the measured value acquisition, wherein:
a synchronization unit for the phase synchronization of the local clock signals in the measuring subunits of the measuring system on the basis of a synchronization signal; and
the synchronization signal is transmitted together with a further signal via a common signal line.

18. The triggerable coordinate measuring system as claimed in claim 17 , wherein:
the synchronization signal is transmitted together with the trigger signal as combined clock-trigger signal in the measuring system.

Assignees

• Fritsch Robert
• Hexagon Technology Ct Gmbh

Inventors

• Fritsch Robert

Classifications

• G01D21/02

  Measuring two or more variables by means not covered by a single other subclass · CPC title

• G01D5/2448 Primary

  Correction of gain, threshold, offset or phase control · CPC title

• H04L7/04 Primary

  Speed or phase control by synchronisation signals {(H04L7/0075 takes precedence)} · CPC title

• G01D5/244 Primary

  influencing characteristics of pulses or pulse trains; generating pulses or pulse trains · CPC title