Implementation of evaluation and sequence criteria in light grid

Patent metadata

Field	Value
Publication number	US-10401531-B2
Application number	US-201715446342-A
Country	US
Kind code	B2
Filing date	Mar 1, 2017
Priority date	Mar 4, 2016
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

A light grid and a method using a light grid include a transmission unit having a plurality of light transmitters for transmitting light beams and a reception unit having a plurality of light receivers for receiving the light beams of the light transmitters. The transmission unit and the reception unit are spaced apart from one another and are disposed opposite one another. A monitored field is formed by oppositely disposed light transmitters and light receivers for detecting objects. The light transmitters are activated one after the other in cycles and the light receivers are evaluated in these cycles. A programmable evaluation unit is provided for evaluating the received signals of the light receivers of a cycle with reference to predefined beam evaluation criteria and forming an intermediate result therefrom. The evaluation unit evaluates at least one intermediate result of a cycle with reference to at least one predefined sequential criterion.

First claim

The invention claimed is:

1. A light grid comprising
a transmission unit having a plurality of light transmitters for emitting light beams;
a receiving unit having a plurality of light receivers for receiving the light beams, the transmitting unit and the receiving unit facing one another and are disposed opposite one another, forming a monitored field for detecting objects established by opposing light transmitters and light receivers; wherein the light transmitters can be activated one after the other in cycles and the light receivers can be evaluated in these cycles;
a programmable evaluation unit provided in the receiving unit, the evaluation unit configured to evaluate received signals of the light receivers of a cycle with reference to predetermined beam evaluation criteria and to form an intermediate result therefrom,
wherein the intermediate result storable in a memory;
wherein non-relevant information of received signals is discarded after evaluation with the beam evaluation criteria of the evaluation unit and information of received signals which do not allow evaluation by beam evaluation criteria because they do not correspond to the predetermined beam evaluation criteria, eliminating a need for storage space, and discarding the information of received signals which do not allow evaluation by beam evaluation criteria after evaluation with the beam evaluation criteria of the evaluation unit,
wherein and the evaluation unit evaluates at least one intermediate result of a respective cycle with reference to at least one respective predefined sequential criterion
and wherein the evaluation unit is also configured to output at least one output signal at least one output on the basis of the evaluated intermediate result;
the beam evaluation criteria being predefined and at least one of the following beam evaluation criteria being adjustable:
a predetermined fixed light beam is interrupted,
a predetermined fixed light beam is not interrupted but free,
a central light beam is interrupted,
a central light beam is not interrupted, but free,
a first light beam is interrupted,
a first light beam is not interrupted, but free,
a continuously connected number of light beams is interrupted,
a continuously connected number of light beams is not interrupted, but free,
one last light beam is interrupted,
one last light beam is not interrupted, but free,
a predetermined fixed number of light beams is interrupted,
a predetermined fixed number of light beams is not interrupted but free, and
the sequence criteria are predefined and at least one of the following sequence criteria is adjustable:
branching when a set beam evaluation criterion is fulfilled,
time recording until a set beam evaluation criterion is fulfilled,
acquisition of a counter reading,
delete an intermediate result flag,
save an intermediate result flag,
logical OR operation of intermediate results,
logical AND operation of intermediate results,
invert intermediate results,
changing a function, setting or configuration of the light curtain,
read at least one input value of at least one input.

2. The light grid in accordance with claim 1 , wherein the evaluation unit accepts programming via a personal computer and a graphical programming software.

3. The light grid in accordance with claim 1 , wherein a function of the light grid, a setting of the light grid or a configuration of the light grid is at least
one switching threshold;
one input configuration;
one output configuration;
one transmission power;
one reception sensitivity;
and/or one cycle time.

4. A method of using a light grid comprising:
a transmission unit having a plurality of light transmitters for transmitting light beams and a reception unit having a plurality of light receivers for receiving the light beams of the light transmitters, and a programmable evaluation unit that is provided in the reception unit, the transmission unit and the reception unit facing one another and disposed opposite one another; wherein a monitored field formed by oppositely disposed light transmitters and light receivers provides detection of objects, and wherein the light transmitters are activated successively in cycles and the light receivers are evaluated in these cycles;
a programmable evaluation unit provided in the receiving unit,
wherein the evaluation unit evaluates the received signals of the light receivers of a cycle with reference to predetermined beam evaluation criteria and wherein an intermediate result is formed therefrom,
wherein the intermediate result is stored in a memory, and discarding non-relevant information of received signals after evaluation by the evaluation unit,
wherein information of received signals which do not allow evaluation by beam evaluation criteria because they do not correspond to predetermined beam evaluation criteria is discarded so that they are not stored, whereby no storage space is required,
wherein the information of received signals which do not allow evaluation by beam evaluation criteria is discarded after evaluation with the beam evaluation criteria of the evaluation unit,
wherein the evaluation unit evaluates at least one intermediate result in each case of a cycle using in each case at least one predetermined sequence criterion,
and wherein the evaluation unit outputs at least one output signal at least one output on the basis of the evaluated intermediate result, the beam evaluation criteria being predefined and at least one of the following beam evaluation criteria being set:
a predetermined fixed light beam is interrupted,
a predetermined fixed light beam is not interrupted but free,
a central light beam is interrupted,
a central light beam is not interrupted, but free,
a first light beam is interrupted,
a first light beam is not interrupted, but free,
a continuously connected number of light beams is interrupted,
a continuously connected number of light beams is not interrupted but free,
one last light beam is interrupted,
one last light beam is not interrupted, but free,
a predetermined fixed number of light beams is interrupted,
a predetermined fixed number of light beams is not interrupted but free, and
the sequence criteria are predefined and at least one of the following sequence criteria is set:
branching when a set beam evaluation criterion is fulfilled,
time recording until a set beam evaluation criterion is fulfilled,
acquisition of a counter reading,
delete an intermediate result flag,
save an intermediate result flag,
logical AND operation of intermediate results,
inversion of intermediate results,
changing a function, setting or configuration of the light curtain, reading in at least one input value of at least one input.

5. The method in accordance with claim 4 , wherein the evaluation unit accepts programming via a personal computer and a graphical programming software.

6. The method in accordance with claim 4 , wherein the setting or configuration of the light grid is at least one switching threshold;
one input configuration;
one output configuration;
one transmission power;
one reception sensitivity;
and/or one cycle time.

Assignees

• Sick Ag

Inventors

• Bürger Jürgen
• Kienzler Stefan
• Herrmann Ralf

Classifications

• F16P3/14

  the means being photocells or other devices sensitive without mechanical contact · CPC title

• G01V8/20 Primary

  using multiple transmitters or receivers · CPC title