Machining Center Probe Signal Multiplexing via Time Division

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Solution Overview

Problem

Machining centers with two spindles face challenges in simultaneous workpiece measurement due to signal collisions and increased costs from requiring separate receiving sections for each transmission channel, leading to extended measurement times and inaccurate results.

Innovation Solution

A method where data telegrams from multiple measuring probes are sent via a common transmission channel, each with a unique identifier and ordinal number, ensuring constant cycle times and varying pause times to prevent collisions, allowing for parallel operation with a single receiving part.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate receiving sections are used for each transmission channel to avoid signal collisions, then measurement reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple receiving sections into a single receiving part that can process signals from multiple measuring probes through a common transmission channel. The receiver uses time-division multiplexing to distinguish and process individual probe signals sequentially, eliminating the need for separate receiving sections while maintaining measurement reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single receiving part is designed with universal functionality to handle signals from multiple different measuring probes. It can identify and process signals from any connected probe using identifier recognition and time-division techniques, making one receiver perform the function of multiple dedicated receivers.

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

2Reliability

If optical systems use light signals of different wavelengths or radio systems use different carrier frequencies for two measuring sensors, then signal collision is avoided, but device complexity and cost increase due to separate receiving sections

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements periodic action by assigning different time slots to different measuring probes for signal transmission. Each probe transmits its signals in alternating time intervals through the common transmission channel, preventing signal collisions without requiring different wavelengths or frequencies. The receiver synchronizes with these periodic transmission patterns to correctly identify and process each probe's signals.

Inventive Principle:
Principle #19Periodic action

3Reliability

If channel separation is implemented in optical systems using directed flashes of light, then signal collision is avoided, but measurement time increases due to sequential operation

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoidmeasurement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system uses periodic time-division multiplexing where different measuring probes transmit signals in alternating time slots through the common channel. This allows for structured sequential access that prevents collisions while maintaining efficient signal transmission. The receiver is synchronized to expect signals from different probes at predictable intervals.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system incorporates feedback mechanisms where the receiver acknowledges received signals and the controlling system coordinates transmission timing based on this feedback. This ensures that probes transmit only when the channel is ready, preventing collisions without requiring extended sequential measurement procedures.

Inventive Principle:
Principle #23Feedback

4Reliability

If modulation frequencies are used differently for two measuring probes, then signal differentiation is achieved, but measurement accuracy decreases due to mutual interference and disturbance

Engineering Contradiction:
Improvesignal differentiationVSAvoidmeasurement precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

Instead of using different modulation frequencies that cause mutual interference, the patent uses periodic time-division multiplexing where each probe transmits with its own identifier in designated time slots. This eliminates frequency-based interference while maintaining clear signal differentiation through temporal separation and identifier recognition.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2803943B1Method for transmitting measurement signals in a machining centre with two or more spindles; measuring probe and receiver for the method
Publication Date: 2018.02.07 BLUM NOVOTEST
  • EP2803943B1 patent drawingFigure 1~2a
  • EP2803943B1 patent drawingFigure 2b
  • EP2803943B1 patent drawingFigure 2c~2e

AI summary

The method presented here serves to transmit data telegrams from at least two measuring probes, each mounted in a spindle of a machining center. The data telegrams are transmitted by the respective measuring probe via a common transmission channel for reception by the receiving unit. Two or more data telegrams are transmitted at a time, each containing information characteristic of the respective measuring probe, a characteristic identifier for the respective measuring probe, and an sequential number of the data telegram with which the characteristic information for the respective measuring probe is transmitted. A substantially constant cycle time elapses between the start of two data telegrams from a measuring probe with the same sequential number. A substantially constant pause time elapses between successive data telegrams from a measuring probe with different sequential numbers.The pause time between data telegrams varies for each of the respective measuring probes depending on the number of measuring probes communicating with the receiver in the machining center, the cycle time of each measuring probe between two of its data telegrams with the same ordinal number and/or a transmission time for a single data telegram.