Inductive sensor question
April 25, 2018 05:18PM
Hi everyone,

I've got an inductive sensor fitted to my printer but it struggles to sense the aluminium heater bed through 3mm glass plate.

Has anyone ran their inductive sensors off more than 12v? Do you get a greater sensing distance? And are there any handy calculators for voltage divider networks?

Cheers

Joe
Re: Inductive sensor question
April 25, 2018 06:03PM
I have two inductive sensors designed for 12v that I have been running on 5 volts for almost 2 years. "TL-W3WC2". One on my 12volt supplied 3D Printer the other on my 24Volt supplied 3D Printer.
Thought I could make make it better by increasing the voltage to 12/24 volts though nothing changed when the voltage was increased.

Omron Has many sensors that have a Sensing distance greater than 3MM

Below is a few to choose from 5mm, 7mm and 12mm or more
DC 2-Wire Models

17 × 17 5 mm TL-Q5MD1 2M *1 *2 TL-Q5MD2 2M *1
25 × 25 7 mm TL-N7MD1 2M *1 TL-N7MD2 2M *1
30 × 30 12 mm TL-N12MD1 2M *1 TL-N12MD2 2M *1
40 × 40 20 mm TL-N20MD1 2M *1 TL-N20MD2 2M *1

Not sure what inductive sensors you have though there is probably better Sensing distance sensor in the same Manufacture/Style as your own.
Re: Inductive sensor question
April 26, 2018 01:48AM
I have 8mm and 12mm diameter sensors. To improve senitivity of the 8mm sensor, I wrapped a strip of thick aluminum foil around the lower part and then adjusted the foils height until the sensor just doesn't trigger anymore. That added another 1mm to the trigger height. (YMMV). Depending on the thickness of the aluminum bed, it might work out for you. But 3mm glass is a tough task.

The 12mm sensor is the safest way to go, but bulky/heavy.

Edited 1 time(s). Last edit at 04/26/2018 01:49AM by o_lampe.
Re: Inductive sensor question
April 26, 2018 07:09AM
Quote
o_lampe
I have 8mm and 12mm diameter sensors. To improve senitivity of the 8mm sensor, I wrapped a strip of thick aluminum foil around the lower part and then adjusted the foils height until the sensor just doesn't trigger anymore. That added another 1mm to the trigger height. (YMMV). Depending on the thickness of the aluminum bed, it might work out for you. But 3mm glass is a tough task.

The 12mm sensor is the safest way to go, but bulky/heavy.

Thanks for the tip about the foil! I'm using an 18mm sensor, unfortunately it's struggling with the 3mm glass. Increased voltage to 24v but no significant increase in sensing distance.

Just out of interest, do most people use 1mm glass?
Re: Inductive sensor question
April 26, 2018 09:58AM
The sensing distance is reduced for non-ferrous metals. The datasheet should have a table of metals and their sensing distances. Aluminum is generally detected at 11-30% of the nominal sensor range.
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