Quality indicator:

Weak illumination:

e.g.

50 LSB

Status & reason:

The signal has a reduced accuracy, because it is above, but close to the noise level.

Action:

Increase integration time for the next measurement

Quality indicator:

Sufficient illumination:

e.g.

Status & reason:

The signal quality and the accuracy is sufficient and not close to any limits. Noise level may be increased.

Action:

No action necessary. See note below

Quality indicator:

Excellent illumination:

Status & reason:

The signal quality and the accuracy is excellent and not close to any limits.

Action:

No action necessary. See note below

Quality indicator:

Too bright illumination:

Status & reason:

The signal is close to or above the limit of too much light (maximum signal limit).

Action:

Decrease integration time for the next measurement. See note below

Note:

Generally, the higher the received signal, the better and more precise the distance measurement will be. However, it is good practice to

control the integration time such that an amplitude value between 100 ... 200 LSB is achieved. Higher values will only slow down the acqui-

sition rate due to longer integration times, but are not significantly improving signal to noise ratio.

The rules to apply are the same as for the modulated light amplitude.

The quality indicator for the distance noise is the ratio AMR of ambient-light to the modulated light. This value may be calculated and used

additionally to the above amplitude value if the respective application is subject to intense ambient light.

Quality indicator:

Ratio AMR of ambient-light to modulated light

AMR

[dB] = 20⋅log

E

AC

)

e.g.

AMR

[dB] = 20⋅log

16

μ W/cm

2

ity, integration time and operating range.

Status & reason:

This ratio is one of the influencing factors regarding the distance noise (refer to Table 2, section Distance noise)

Action:

< 60 dB: excellent

No action necessary.

< 70 dB: sufficient

Is a lower noise level needed, do the next measurement with a longer integration

time or an increased illumination power.

> 70 dB: weak

Do the next measurement with a longer integration time or an increased illumination

power.

There are also validity indicators delivered by the chip after a measurement. These will help to detect saturated pixels as a result of too

much illumination or too long integration time.

Validity indicator:

Status “Saturation” of a pixel is set for one ore more of the DCSx values.

Refer to chapter 3.5.5.: Command: READ Saturated pixels

Status:

The pixel receives too much light.

Reason:

Fault conditions:

- Too much modulated light-signal or too reflective object.

- Too much ambient-light.

Action:

Dump data and repeat the measurement with a decreased integration time or measure the ambient-light.

Validity indicator:

Maximum signal limit: one or more of the DCSx values per pixel

≥ 1'000 LSB

Status:

Suggests there is an object, but it is out of the usable operating range.

Reason:

Fault conditions:

- The object is too reflective.

- It is too close to the sensor.

- There is too bright illumination or too much modulation signal is emitted.

Action:

Dump data and repeat the measurement with a decreased integration time.

Validity indicator:

Noise level limit: All DCSx values per pixel

≤ 50 LSB

Status:

There is a lack of signal or no usable receiver signal.

The received signal is in the noise level. The accuracy of the distance calculation is out of tolerance.

Reason:

Regular operation: - Absence of an object in the operating range.

Fault conditions:

- The object has too little remission (reflectivity).

- It is too far away.

- The illumination is too dim. Too little modulation signal is emitted.

Action:

Dump data and repeat the measurement with an increased integration time.

Table 7 shows a quality decision matrix as a summary of the validity and quality parameters for the distance measurement.

© 2014 ESPROS Photonics Corporation

Characteristics subject to change without notice

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Datasheet epc610 - V1.7

www.espros.ch