METHOD FOR CONTROLLING AT LEAST ONE LIGHT BARRIER, CONTROL CIRCUIT AND THUS EQUIPPED SELF-SERVICE TERMINAL

• US 20160255696A1
• Filed: 02/23/2016
• Published: 09/01/2016
• Est. Priority Date: 02/26/2015
• Status: Active Grant

• Current Assignee: Diebold Nixdorf Systems GmbH (Diebold Nixdorf, Incorporated)
• Original Assignee: Wincor Nixdorf International GmbH (Diebold Nixdorf, Incorporated)
• Inventors: Pawlak, Thorsten
• Granted Patent: US 10,104,736 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01V 8/12 using one transmitter and one receiver
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/395 Linear regulators
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

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.

Claims

1. A method (1000) for controlling at least one light barrier (108), wherein light (L) is emitted from an optical transmitter (T) to an optical receiver (R), wherein a current reception level (RV) is determined in dependence from the received light (L), and wherein a control circuit (110) is used to check whether the current reception level (RV) falls below a lower threshold (TH1) or exceeds an upper threshold (THh) to determine whether the light barrier (108) is interrupted or not, the method comprising:

adjusting the thresholds (TH1;

THh) initially in dependence on a predetermined minimum reception level (TVm) so that each of the thresholds (TH1;

THh) is a fraction of the minimum reception level (TVm);

defining an allowable reception level range (RNG) between the minimum reception level (TVm) and a predetermined saturation reception level (SL); and

checking in a first sequence of steps (1100) whether the current reception level (RV) is outside the allowable reception level range (RNG) (step 1112), and, if the current reception level (RV) is outside the allowable reception level range (RNG),

calibrating, in a second sequence of steps (1200), at least a parameter (SC) for the operation of the optical transmitter (T) in dependence on the minimum reception level (TVm) and/or the saturation reception level (SL) (1232).

2. The method (1000) of claim 1, wherein the second sequence of steps (1200) comprises calibrating a parameter (SC) that indicates an operating current for the operation of the optical transmitter (T) in dependence on the minimum reception level (TVm) and the saturation reception level (SL) (1231, 1232).

3. The method (1000) of claim 2, wherein, after recalculating and adjusting (steps 1231, 1232) the parameter that indicates the operating current for the operation of the optical transmitter (T), the second sequence of steps (1200) further comprises verifying (block 1240) the current reception level (RV) by checking whether the current reception level (RV) is lower than the minimum reception level (TVm) (step 1242), and if the current reception level (RV) is lower than the minimum reception level (TVm), the method comprises recalculating and adjusting the thresholds (TH1;

THh) in dependence on the current reception level (RV) (steps 1244, 1245), and if the current reception level (RV) is not lower than the minimum reception level (TVm) the method comprises reusing the already adjusted thresholds (TH1;

THh) (steps 1243, 1245).

4. The method (1000) of claim 3, wherein each of the readjusted thresholds (TH1 THh) is a fraction of the current reception level (RV).

5. The method (1000) of claim 1, wherein the lower threshold (TH1) is adjusted so that the fraction is 30%-60% of the minimum reception level (TVm) or the current receiving level (TV), and that the upper threshold (THh) is adjusted so that the fraction is 60%-90% of the minimum reception level (TVm) or the current receiving level (TV).

6. The method (1000) of claim 1, wherein the upper threshold (THh) is adjusted so that it is at least 10% higher than the lower threshold (TH1).

7. The method (1000) of claim 1, wherein, if the current reception level (RV) is above the saturation reception level (SL) (step 1212), the calibrated parameter (SC) that indicates the operating current for the optical transmitter (T) is reduced successively (steps 1213, 1214) until the current reception level (RV) at the receiver (R) is below the predetermined saturation reception level (SL).

8. The method (1000) of claim 1, further comprising calibrating the parameter (SC) that indicates the operating current for the optical transmitter (T) by calculating a gradient (grad;

gradI) of one characteristic curve (I) of the light barrier (108) (1221) and readjusting the parameter (SC) to a target value (TC) that is calculated in dependence on the gradient (gradI) (Steps 1231, 1232).

9. The method (1000) of claim 8, wherein the gradient (grad) is calculated under an assumption that the respective characteristic curve (I, II, III) starting from the zero point is linear first, so that the gradient (grad) is calculated by the following formula (1221):

grad=RV*w/SC,

where RV is the current reception level, w is a weighting factor and SC is the adjusted parameter that specifies the operating current of the optical transmitter (T).

10. The method (1000) of claim 8, wherein the target value (TC) for the parameter (SC) is calculated by the following formula (1231):

TC={TVm+(SL−

TVm)/2}*w/grad,

where TVm is the minimum reception level;

SL is the saturation reception level;

w is a weighting factor and grad is the calculated gradient.

11. The method (1000) of claim 8, wherein the second sequence of steps (1100) further comprises verifying if the light barrier (108) is covered (Block 1220) by checking whether the calculated gradient (gradI) is lower than a minimum gradient value (milliGradientCovered), and if the light barrier (108) is covered, the second sequence of steps (1200) does not calibrate the parameter (SC) for the operation of the optical transmitter (T), or if the light barrier (108) is not covered the method further comprises recalculating and adjusting the parameter (SC) that indicates the operating current for the optical transmitter (T) in dependence on the minimum reception level (TVm), the saturation reception level (SL) and the calculated gradient (gradI) (steps 1231, 1232).

15. A self-service terminal (100) comprising the control circuit (110) of claim 11 and at least one light barrier (108) connected thereto, the at least one light barrier (108) having an optical transmitter (T) and an optical receiver (R) to which the transmitter (T) emits light (L) and being connectable to the control circuit (110).

16. The self-service terminal (100) of claim 15, further comprising at least one slave controller (110) that is connected to the at least one light barrier (108), and a master controller (112) that is connected to the at least one slave controller (110).

12. A control circuit (110) for controlling at least one light barrier (108) that is used with an optical transmitter (T) that emits light (L) to an optical receiver (R), the control circuit (110) is connected to the receiver (R) or to a downstream converter stage (CNV) and determines an actual reception level (RV) in accordance with the received light (L), and the control circuit (110) checks whether the current reception level (RV) falls below a lower threshold (TH1) or exceeds an upper threshold (THh), to determine whether the light barrier (108) is interrupted or not, the control circuit comprising:

a connection to the optical transmitter (T) or to an upstream driver stage (DRV) for controlling operation of the optical transmitter (T);

the control circuit (110) being configured to initially adjust the thresholds (TH1, THh) in dependence on a predetermined minimum reception level (TVm) so that each of the threshold values (TH1;

THh) is a fraction of the minimum reception level (TVm), wherein

an allowable receiving level range (RNG) is defined between the minimum reception level (TVm) and a predetermined saturation reception level (SL), and wherein the control circuit (110) checks in a first sequence of steps (1100) whether the current reception level (RV) is outside of this allowable reception level range (RNG) (step 1112), and if the current reception level (RV) is outside of this allowable reception level range (RNG), the control circuit (110) calibrates in a second step sequence (1200) at least a parameter (SC) for the operation of the optical transmitter (T) in dependence on the minimum reception level (TVm) and/or the saturation reception level (SL) (1232).

13. The control circuit of claim 12, wherein the control circuit is incorporated into at least one control unit (110, 112) that comprises at least one slave controller (110) that is connected to the at least one light barrier (108), and a master controller (112) that is connected to the at least one slave controller (110).

14. A light barrier (108) comprising an optical transmitter (T) and an optical receiver (R) to which the transmitter (T) emits light (L) the light barrier being connectable to the control circuit of claim 12.