how to calibration 6180

[Zwf.1]

hi，st

I am using a 6180 to measure the height of milk. The height of vl6180 from the milk is about 10 - 60mm，anf the front of the sensor is covered with a layer of clear plastic. I don't know how to do the offset calibration.

1. Remove the covering plastic for calibration or bring the plastic on for calibration?

2. The calibration process on the specification uses a 88% reflectance target of 50mm. Can the value of 50mm be changed? Can it be calibrated directly with milk

3. Does the cross talk calibration have to use a black target 100mm for calibration?

thanks �?

[Zwf.1]

As in the picture, there is a chance that the cover will be stained with milk. At this time, the measured value is wrong. Is there a way to reduce this effect? I've tried adding a baffle between the tx and rx, but it's basically useless for this case.

[John E KVAM]

Your issue is crosstalk. You must read and understand what crosstalk is.

go to:

https://community.st.com/s/article/Time-of-Flight-Cover-glass

It's a short article that will point you to other resources.

Then go to www.hornix.com.tx

This company molds optical quality plastics. They have a crosstalk free coverglass. Go to their products page and scroll almost to the bottom. Look for the coverglass that has a barrier between the Tx and Rx sides. This will keep the photons from short-circuiting the system and giving you that short answer.

Note there are 3 products - the one you want is the one on the right. That ridge is made of opaque plastic and extends all the way to the chip. It prevents the light from crossing over to the receive side no matter how dust, dirt, or milk gets on it. You must either use this, or invent something like it.

• john

[John E KVAM]

The RangeIgnore does not do what you think it does. It insures you ignore the photons from your coverglass.

If your coverglass returns some photons we need to subtract them from the range calculation and insure they do not create a 'ghost' target when there is none.

Generally during crosstalk calibration we set that value to 1.5 times the crosstalk value.

but then if your coverglass gets dirty, you will range on that dirt. So we can prevent a false target by increasing the RangeIgnore value.

-john

[Zwf.1]

hello

[Zwf.1]

Hello, can you help me with this last question

[Zwf.1]

Hello, can you help me with this last question

[John E KVAM]

The easy way to solve your problem is to go to www.Hornix.com.tw and buy the coverglass with the raised barrier between the TX and the RX side of the sensor. (From the products tab, go almost all the way to the bottom).

this coverglass creates a near-perfect barrier between the TX and the RX side. If you get enough dirt on the sensor you might blind it but you will never get a wrong answer. And if you get no answer, you have to indicate to the user he has to clean the lens.

There is no real trick to the Hornix cover, except the molding of the two plastics. One clear one (to 950nm) above the optical elements and the opaque one everywhere else. That and a very tight fit is what you need.

And sorry about the slow answer, not sure why I was not being notified.

• john

[Zwf.1]

Sorry, your answer was folded, I didn't see it and asked a few more times, thank you very much