Method for controlling at least one light barrier, control circuit and thus equipped self-service terminal
First Claim
1. A method for controlling at least one light barrier, the method comprising the steps of:
- initially adjusting a lower threshold and an upper threshold based on a predetermined minimum reception level so that each of the lower and upper thresholds is a fraction of the predetermined minimum reception level;
emitting light from an optical transmitter to an optical receiver;
determining a current reception level based on light received by the optical receiver;
checking whether the current reception level falls below the lower threshold or exceeds the upper threshold to determine whether the light barrier is interrupted;
defining an allowable reception level range between the minimum reception level and a predetermined saturation reception level; and
checking whether the current reception level is outside an allowable reception level range;
when the current reception level is outside the allowable reception level range, calibrating at least a first parameter for the operation of the optical transmitter based on the minimum reception level and/or the saturation reception level;
when the current reception level is above the predetermined saturation reception level, reducing the first parameter successively until the current reception level at the optical receiver is below the predetermined saturation reception level;
wherein the step of calibrating at least the first parameter comprises the step of calibrating an operating current for the operation of the optical transmitter based on the minimum reception level and/or the predetermined saturation reception level; and
wherein the step of calibrating the operating current further comprises the step of calculating a gradient of one characteristic curve of the light barrier and readjusting the first parameter to a target value that is calculated based on the gradient.
10 Assignments
0 Petitions
Accused Products
Abstract
A method controls a light barrier where light is emitted from an optical transmitter to an optical receiver. The method checks whether reception levels fall below a lower threshold or exceed an upper threshold to determine whether the light barrier is interrupted. The thresholds initially are adjusted based on a predetermined minimum reception level, with each threshold being a fraction of the minimum reception level. An allowable reception level range is defined between the minimum level and a predetermined saturation level. The method checks whether the current reception level is outside the allowable reception level range, and, if this is the case, calibrates a parameter for operating the optical transmitter based on the minimum reception level and/or the saturation reception level. The parameter is calibrated by calculating a gradient of one characteristic curve of the light barrier and readjusting the parameter to a target value calculated based on the gradient.
8 Citations
14 Claims
-
1. A method for controlling at least one light barrier, the method comprising the steps of:
-
initially adjusting a lower threshold and an upper threshold based on a predetermined minimum reception level so that each of the lower and upper thresholds is a fraction of the predetermined minimum reception level; emitting light from an optical transmitter to an optical receiver; determining a current reception level based on light received by the optical receiver; checking whether the current reception level falls below the lower threshold or exceeds the upper threshold to determine whether the light barrier is interrupted; defining an allowable reception level range between the minimum reception level and a predetermined saturation reception level; and checking whether the current reception level is outside an allowable reception level range; when the current reception level is outside the allowable reception level range, calibrating at least a first parameter for the operation of the optical transmitter based on the minimum reception level and/or the saturation reception level; when the current reception level is above the predetermined saturation reception level, reducing the first parameter successively until the current reception level at the optical receiver is below the predetermined saturation reception level; wherein the step of calibrating at least the first parameter comprises the step of calibrating an operating current for the operation of the optical transmitter based on the minimum reception level and/or the predetermined saturation reception level; and wherein the step of calibrating the operating current further comprises the step of calculating a gradient of one characteristic curve of the light barrier and readjusting the first parameter to a target value that is calculated based on the gradient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A control unit for controlling at least one light barrier that is used with an optical transmitter that emits light to an optical receiver, the control unit comprising:
-
an input connected to the optical receiver, the input configured to receive a current reception level in accordance with light received by the optical receiver; a control circuit configured to check whether the current reception level falls below a lower threshold or exceeds an upper threshold to thereby determine whether the light barrier is interrupted; an output connected to the optical transmitter for controlling operation of the optical transmitter; and wherein the control circuit is configured to adjust the lower and upper thresholds based on a predetermined minimum reception level so that each of the lower and upper thresholds is a fraction of the predetermined minimum reception level, wherein the control circuit is configured to define an allowable reception level range between the minimum reception level and a predetermined saturation reception level; wherein the control circuit is configured to determine whether the current reception level is outside of the allowable reception level range, and, when the current reception level is outside of the allowable reception level range, the control circuit is configured to calibrate at least a first parameter for the operation of the optical transmitter based on the minimum reception level and/or the predetermined saturation reception level, the first parameter being operating current; and wherein, when the control circuit determines that the current reception level is above the predetermined saturation reception level, the control circuit is configured to reduce the first parameter successively until the current reception level at the optical receiver is below the predetermined saturation reception level; and wherein the control circuit is further configured to calculate a gradient of one characteristic curve of the light barrier and readjust the operating current to a target value that is calculated based on the gradient. - View Dependent Claims (10, 11, 12, 13, 14)
-
Specification