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Infrared Sensor (Back Scattering)
Measurement of Suspended Solid (in pipe line) using infrared back scattering principle.

Hi all,

I have a sensor that used to measure suspended solid in sludge. It's not working. When I apply 12 V source, I receive 10 volt signal using LabVIEW but the signal never change even when i put my hand or whatever in front of the Lens (IR LED). Its built in photo diode i can not get access to it, so i need to be sure a confirmation is it the IR LED fault? why i still receive 10 volt?

One more thing please, a proper way to calibrate this sensor? (i have only the probe).

Thank you very much and i am looking forward to hear from you.

By W.L. Mostia on 6 June, 2017 - 6:23 pm
2 out of 2 members thought this post was helpful...

It might help if you provide the brand and model of the sensor.

Make sure that you have supplied the correct power supply voltage and have the sensor wired correctly. Verify based on the part number that the output is a voltage and not a current or that it is a switch. Verify that the sensor output matches up with the I/O card you are sending it to. You can also read the sensor output when it is not connected to the I/O card to see if the sensor works when it is not connect to the I/O card. That is about it without more information.

William (Bill) L. Mostia, Jr. PE
ISA Fellow, FS Eng. (TUV Rheinland)

"No trees were killed to send this message, but a large number of electrons were terribly inconvenienced." Neil deGrasse Tyson

Any information is provided on a Caveat Emptor basis.

Hi,

Thanks William for your post. the sensor is IL55 Partech model. the supply voltage is 12 volt, and i still couldn't find a clue.

looking forward to hear from you.

Thank you
Maj

Which monitor, the 8100/8200 or 7200 Monitor, is the IL55 connected to?

> Which monitor, the 8100/8200 or 7200 Monitor, is the IL55 connected to?

i don't have either monitor. i am using Labview data acquisition system.

2 out of 2 members thought this post was helpful...

The spec sheet clearly states that the IL55 sensor is intended for use with a Partech analyzer/Montior.

"The sensor uses 180 Back Scatter of infrared light to detect the presence of solids in the pipe, the sensor electronics provides an output signal that is used by either the 8100/8200 or 7200 Monitor to infer the level of Sludge Density, Suspended Solids or Turbidity. "

The spec sheet also states:
Power Supply Voltage: 12VDC from 7200 Monitor
Interface to Monitor Type: 0 - 5 mA (linearised by Monitor)

note the action of the monitor - providing a 'linearised" signal.

There appears to be no openly published information on using an IL55 as a stand alone sensor. You might inquire of the manufacturer, but they're likely to tell you to buy a monitor.

Hi,

Thank you for your reply,

just to be clear, are you saying without the 7500 monitor i can not operate this probe?

i just want an output signal from the sensor (voltage) with no calibrated signal, for example in the air i send signal and i Receive signal back thats all i need so i presume any data acquisition system can do that, so back to my question is there a possibility of the damaged IR LED or Photo diode?

finally about the data sheet i didn't get whats mean by the sensor output signal is 5 mA, could you please explain to me more.

Thank you

By W.L. Mostia on 12 June, 2017 - 3:58 pm
1 out of 1 members thought this post was helpful...

Why don't you use a DVM and figure out what the signal is? In regards to a current signal of 5 mA, this could mean that the output signal is 0-5 mA. Put a 200 ohm resistor from the signal connection to the signal return (DC negative). Read the voltage across the resistor while varying the sensor input and see if the signal varies 0-1 volts


William (Bill) L. Mostia, Jr. PE
ISA Fellow, FS Eng. (TUV Rheinland)
WLM Engineering Co.

"No trees were killed to send this message, but a large number of electrons were terribly inconvenienced." Neil deGrasse Tyson

Any information is provided on a Caveat Emptor basis.

Thanks William,

the end connection is 4 wires goes to built in LED and Photodiode (I have no access). these wires I can measure 10V using DVM and 5V (each two wires gives different reading)! I don't know which wire goes to the LED and which wire goes to Photodiode?

this signal not changing when I put any object in front of the LED.

I tracked the circuit a little bit and the end of the circuit 5 volt and 39Ohm which means 120 mA the LED driver I think.

so is the problem with LED and the photodiode?

hope that make it more clear

thank you

By W.L. Mostia on 13 June, 2017 - 6:08 pm

First, 4 wire in a sensor normally indicate two wires for power (+ & -) and two for the signal (signal + and signal return -) If you have a LED and a photodiode, my guess is the LED send out light which bounce off or through something back to the photo diode. See manual below.


Manual https://www.partech.co.uk/wp-content/uploads/2014/05/163790IM-Iss06.pdf

INSTRUCTION MANUAL IL55 and IL55BV2 Sensor In Line Sludge Density and Turbidity Sensor

Send Partech an e-mail or call them and explain what you are doing and see if they will help (contact information available in manual().

This data sheet show that the power supply is 12 VDC and the signal 0-5 mA, e.g. two wires for power and two wires for the 0-5 mA output.

http://www.brinck.nl/producten?format=raw&task=download&fid=133

I was unable to find a wiring diagram but in the below manual, there is a wiring color table on page 12 of the instruction manual.

7200 Monitor Field Mount - Partech: https://www.partech.co.uk/wp-content/uploads/2014/05/167300IM-Iss11_7200.pdf

7200 Monitor Instruction Manual 2 Introduction 2.1 General The 7200 Monitor is used for processing and displaying the output signal from a Partech sensor.

Regards,
Bill

William (Bill) L. Mostia, Jr. PE
ISA Fellow, FS Eng. (TUV Rheinland)
WLM Engineering Co.

"No trees were killed to send this message, but a large number of electrons were terribly inconvenienced." Neil deGrasse Tyson

Any information is provided on a Caveat Emptor basis.

Hi William,

I think there is a misunderstood (excuse my English). I already know the wire diagram, its 3 wires, 12V +- and signal that's clear. I did supply the circuit with 12 volt that is clear.

The end of the circuit there are 4 pins these pins (4 wires) connected to the IR LED and photodiode (960nm). I did measure the voltage a cross these 4 pins, the 2 wires goes to LED (the output of the circuit) they gave me 10 volt, other 2 wires are 5 volt.

I still get 10 volt output from the signal wire. I can see that using Labview and Matlab data acquisition software.

I know there is a voltage (10 volt) goes directly to the IR LED. However, when I put an objective in front of the LED (lens), the 10V receiving signal doesn't change which it should change am I right?.

I hope its clearly and looking forward to hear from you.

Many Thanks

>I still get 10 volt output from the signal wire. I can see
>that using Labview and Matlab data acquisition software.

I am confused about this 10V that I received, what is it?
When I put an objective in front of the LED(lens), the 10V receiving signal doesn't change which it should change, am I right?

1 out of 1 members thought this post was helpful...

According the minimal info available, the sensor output is a mA (current) signal, not a voltage signal.

Put a mA meter in series with the output and see whether the signal modulates with varying backscatter.

By W.L. Mostia on 14 June, 2017 - 12:06 pm
1 out of 1 members thought this post was helpful...

Have you checked to see is the output signal is a current signal like it specs state? I believe that this sensor is typically used as a turbidity sensor and a signal with full reflection would always be 100%. As the turbidity increases, more IR is absorbed. You might try putting a liquid with some turbidity in it. Unfortunately I believe that it typically measures sludge of which a sample might not be easily be available. You might try tea or milk. Remember to put a resistor across the output so you can measure current.

William (Bill) L. Mostia, Jr. PE
ISA Fellow, FS Eng. (TUV Rheinland)
WLM Engineering Co.

"No trees were killed to send this message, but a large number of electrons were terribly inconvenienced." Neil deGrasse Tyson

Any information is provided on a Caveat Emptor basis.

Hi All,

I am looking for the best option to choose an LED, Photodiode and lens to use it to measure particles in sludge.

from the circuit I use, the current pushed to the LED limited by a limiting resistor of 39 ohm at 5V that's around 120mA. could you please recommend me which LED, lens and photodiode I can by from the market that can meet my requirement? its backscattering 180 degree measuring in pipeline.

Thank you very much and I am looking forward to hear from you.

thank you very much and yes it works. I put 200ohm as you mention and I am able to see changes in my signal from 0.4volt to 1volt.

just one more thing, can I improve the sensitivity by increase resistor value?

also is there away to measure directly mA? I am thinking to use Arduino to monitor the signal is that possible.

Thanks again and appreciate it

By W.L. Mostia on 5 July, 2017 - 6:10 pm
1 out of 1 members thought this post was helpful...

You can increase the size of the resistor to get a larger voltage generated but I don't think that the measurement sensitivity will be improved (e.g.Sensitivity is an absolute quantity, the smallest absolute amount of change that can be detected by a measurement.)

Regards,
Bill

William (Bill) L. Mostia, Jr. PE
ISA Fellow, FS Eng. (TUV Rheinland)
WLM Engineering Co.

"No trees were killed to send this message, but a large number of electrons were terribly inconvenienced." Neil deGrasse Tyson

Any information is provided on a Caveat Emptor basis.

1 out of 1 members thought this post was helpful...

If you look at the IR LED with a cellphone camera it will show as a dull greenish light. I'm guessing that the LED will draw about 10 - 15 milliamps from the 12 Volt supply.

I'm also guessing that the sensor is an IR Diode. It will draw more current as the backscatter increases it probably needs a resistor in series fed from a low Voltage source e.g. 2k from 12 Volts.

When you are working with IR detectors be careful that it's not getting swamped with IR from the room light, especially if you have incandescent lighting.

Hope this helps

Thank you Roy,

I have tried to use the camera on my phone (iPhone) from the first day and nothing. I can see no light at all so I thought the LED is broken. just yesterday I use it my friend phone (Samsung camera) and its working I can see light. I guess its the filtration used in the camera.

thank you very much.