Position Measuring Device Status Signal Encoding

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Solution Overview

Problem

Existing incremental position-measuring devices face challenges in transmitting status reports to subsequent electronics without interfering with position information, often requiring additional wires and risking misinterpretation of status signals as position measurement failures.

Innovation Solution

A position-measuring device with a monitoring unit that outputs status messages by varying the absolute position or number of reference pulses, allowing status reports to be transmitted without additional wires, using a graduation carrier, scanning unit, signal processing unit, and reference signal output unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If additional wires are added to transmit status reports, then status information can be transmitted to subsequent electronics, but the cable complexity and cost increase

Engineering Contradiction:
Improvestatus information transmissionVSAvoidcable complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The reference pulse signal line is made multi-functional by using it to transmit both position reference information and status reports. The same physical cable and signal line that carries the reference pulse for position measurement also carries status information encoded in the timing or presence/absence of reference pulses, eliminating the need for separate status transmission wires.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the status transmission function with the existing reference pulse transmission function. By encoding status information within the reference pulse signal characteristics (such as varying pulse widths, adding pause periods, or modulating pulse timing), two separate functions are combined into a single signal transmission path, reducing cable core requirements.

Inventive Principle:
Principle #5Merging (Combining)

2Loss of information

If status signals are transmitted by varying signal amplitudes, then status information can be conveyed, but position evaluation may be disrupted and system standstill may occur

Engineering Contradiction:
Improvestatus information transmissionVSAvoidposition measurement reliability
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The status information is transmitted using periodic reference pulses rather than continuous amplitude modulation. By varying the timing, presence, or pattern of periodic reference pulses (e.g., adding pause periods between pulses or varying pulse widths while maintaining amplitude), status data is conveyed without continuously disrupting the signal characteristics that position evaluation relies upon.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses the timing and patter of reference pulses as an intermediary carrier for status information, rather than directly modulating the amplitude of position signals. This intermediary approach allows status transmission through temporal characteristics (when pulses occur, how often, their duration) rather than amplitude changes that would directly interfere with position measurement accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the number of wire cores is reduced, then cable cost decreases, but the ability to transmit additional status information is compromised

Engineering Contradiction:
Improvecable simplicityVSAvoidstatus information transmission capability
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The reference pulse signal line is made multi-functional by using it to transmit both position reference information and status reports. The same physical cable and signal line that carries the reference pulse for position measurement also carries status information encoded in the timing or presence/absence of reference pulses, eliminating the need for separate status transmission wires.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables simple and reliable output of status messages to subsequent electronics, reducing the need for extra wires and minimizing the risk of system standstill due to misinterpretation of status signals.

Implementation Method 1

a scanning unit for generating position-dependent scanning signals by scanning the measuring graduation

Methodology Applied
Scientific EffectOptical scanning:

Implementation Method 2

a signal processing unit for processing the scanning signals into incremental position signals

Methodology Applied
Scientific EffectSignal processing:

Implementation Method 3

a reference signal output unit for outputting reference pulses via a reference pulse signal

Methodology Applied
Scientific EffectElectrical signal generation:

Data Source

PatentEP3382348B1Position measuring device and method for operating same
Publication Date: 2020.04.29 DR JOHANNES HEIDENHAIN GMBH
  • EP3382348B1 patent drawingFigure 1
  • EP3382348B1 patent drawingFigure 2
  • EP3382348B1 patent drawingFigure 3

AI summary

The present invention relates to a position measuring device comprising: • a scale carrier (14) on which a measuring scale (16, 17) is arranged, • a scanning unit (12) for generating position-dependent scanning signals (S0, S90, R) by scanning the measuring scale (16, 17), • a signal processing unit (20) for processing the scanning signals (S0, S90, R) into incremental position signals (P0, P90), • a reference signal output unit (50) for outputting reference pulses (REF, SREF) via a reference pulse signal (PR), and • an output interface (40) for outputting the incremental position signals (P0, P90) and the reference pulse signal (PR) to a subsequent electronics unit (80).A monitoring unit (30) is provided from which, based on the monitoring of at least one signal (X) to be monitored, at least one status message (ST) can be output to the reference signal output unit (50), from which the at least one status message (ST) can be output by varying the absolute position and/or the number of reference pulses (REF, SREF). The invention further relates to a method for outputting a status message with such a position measuring device.