i’m kinda worried about my 8mm proximity sensor giving false readings from other metal parts since my entire effector is made of metal.
i’ve never used these sensors before. so i was wondering what you guys thought. I’ve attached photos with measurements.
I think you’re safe. By the look of your design, the sensing end is well clear of things that may trigger it.
Does a motor is mounted on the hotend, is there any magnets near it?
Both could cause errors, aluminium works best and V4A for bolts.
You need to cover it for magnetic influences.
Well best would be to unmount it and try it by hand. if it works then you would know if its mechanical or a software caused problem.
Yes the discs in the photo are neodymium magnets
so you could try to take a piece of aluminum pipe and place the sensor in it. it should work when it is long enough to shield the sensor.
you can try with some layers of alu foil to figure out how it works.
When the is iron between the sensor and the magnets or any other soft metal, you also need to shield that contact.
There are also ‘shielded’ versions of these sensors. Their sensing distance is much shorter however.
And putting pipe/tube around it would only cause more problems.
Nothing near the base of the sensors look like they’ll interfere in any way, I’d just put a sensor side-by-side with a hot-end on your [wooden/plastic] bench and see what happens.
@Electra_Flarefire i would use a shielded one but, they cost a lot more and i really need the distance.
Yeah. To get the same distance you need to go to a much larger sensor. Both of these are around the 7-8mm distance range:
http://www.ebay.com.au/itm//331400444677?
http://www.alibaba.com/product-detail/DC-NPN-NO-M24-three-wire_1188655272.html
Yeah, you’re fine with this.
Your good.
thanks for you input guys. it’s very reassuring.
The unshilded sensors have a mushroom like field but is looks like you will be safe. A general rule the metal free zone around heavy metal is 1x the diameter of the sensor so to be safe keep your heat block is orientated correctly like in your picture and you will be safe. Are you sensing though glass or strainght onto your alloy bed?
@Brad_Smith i’ll probably be sensing though 3mm glass onto a 3mm steel plate.
Steel plate makes life much easier since the sensing distance specified will not change. If you were sensing aluminium the sensing distance would be halved. You could get away with a 12mm diameter unshielded 8mm sensing range sensor and save on weight.
@Brad_Smith yeah i think the exact values are
0.8 for stainless
0.5 for brass
0.4 for aluminum
0.3 for copper
to get the sensing distance just times the number by the sensing distance
@Brad_Smith also i would really like a 12mm diameter 8mm sensor but i could not find any under 18mm. please link me to one if you ever find a source.
@william_foster1 see this link http://www.automationdirect.com/adc/Shopping/Catalog/Sensors_-z-Encoders/Inductive_Proximity_Sensors-z-Proximity_Switches/12mm_Round(AM_-z-VM1-z-PMW-z-PBM_Series)/Extended_Sensing_Distance(AM1_-z-_AM6_Series)/AM1-AP-4A
@Brad_Smith thanks
