Limit Sensor Options / Questions - Onefinity Build
Posted: Sun Jan 29, 2023 5:11 pm
Hi I am trying to convert my Onefinity CNC over to Acorn. I have made great strides with the help from everyone here.
At this point I am trying to put together some parts for my Home / Limit sensors. I was hoping someone could give me some insight before I spend money where I shouldn’t. So I have a few questions?
Does a larger sensor work better? Does it produce a larger/stronger field?
The Centroid website recommends a 2CM sensor from Amazon:
https://www.amazon.com/Twidec-Inductive ... ss_tl&th=1
I was hoping to use a smaller sensor such as a 12mm with a longer sensing distance. I was looking at this one:
https://www.automationdirect.com/adc/sh ... pnm6-cn-4h
Is a longer sensing distance better?
I am hoping to sense my aluminum gantry. From what I understand, you multiply the sensing distance by .4. So a 4mm sensing distance would only give me a 1.6 sensing distance. (I have also read that a larger object will be sensed less than a thinner one due to the dissipation of eddy currents.)
Here is a picture. I was planning on mounting a sensor on top of the Y end-stop and sense the gantry.
Should I use a shielded cable?
These cables will be running in a drag chain with my control and spindle cable. All cables – Including AC – in my setup are shielded. Do these need to be shielded?
If so, I have been using IGUS wire. Does this look OK for limit sensors?
https://www.igus.com/product/442?artNr=CF881-05-03
Also, how much current do these things pull?
The Amazon description says a 300mA output on that sensor. Output???? If each sensor pulls 300mA I am going to have to come up with a different power supply because I think the 24V power supply that came with my Acorn is only 1 amp.
Does anyone know of any good sources for these sensors?
I see the Chinese sensors all over Amazon. Are they any good? I know that some sensors have multiple oscillators and even compensation for swarf buildup… along with a hefty price. I just want something that is reliable and reasonably accurate.
I spent way too long at Mouser, Newark, Digikey, Grainger, McMaster Carr, Amazon, Ebay and such. Most places are sold out or only have 1 or 2 in stock. The Automation Direct sensors linked above require a M12 plug which will evidently add another $10 or $15 to the cost of each…. AD is sold out of the wired version. It is all very frustrating.
Finally, do you think if I mounted a sensor perpendicular to my Z axis that the sensor would pick up the bearing?
Here is another picture:
So if anyone has any suggestions or advice it will be most welcome and appreciated. As always, Thanks.
At this point I am trying to put together some parts for my Home / Limit sensors. I was hoping someone could give me some insight before I spend money where I shouldn’t. So I have a few questions?
Does a larger sensor work better? Does it produce a larger/stronger field?
The Centroid website recommends a 2CM sensor from Amazon:
https://www.amazon.com/Twidec-Inductive ... ss_tl&th=1
I was hoping to use a smaller sensor such as a 12mm with a longer sensing distance. I was looking at this one:
https://www.automationdirect.com/adc/sh ... pnm6-cn-4h
Is a longer sensing distance better?
I am hoping to sense my aluminum gantry. From what I understand, you multiply the sensing distance by .4. So a 4mm sensing distance would only give me a 1.6 sensing distance. (I have also read that a larger object will be sensed less than a thinner one due to the dissipation of eddy currents.)
Here is a picture. I was planning on mounting a sensor on top of the Y end-stop and sense the gantry.
Should I use a shielded cable?
These cables will be running in a drag chain with my control and spindle cable. All cables – Including AC – in my setup are shielded. Do these need to be shielded?
If so, I have been using IGUS wire. Does this look OK for limit sensors?
https://www.igus.com/product/442?artNr=CF881-05-03
Also, how much current do these things pull?
The Amazon description says a 300mA output on that sensor. Output???? If each sensor pulls 300mA I am going to have to come up with a different power supply because I think the 24V power supply that came with my Acorn is only 1 amp.
Does anyone know of any good sources for these sensors?
I see the Chinese sensors all over Amazon. Are they any good? I know that some sensors have multiple oscillators and even compensation for swarf buildup… along with a hefty price. I just want something that is reliable and reasonably accurate.
I spent way too long at Mouser, Newark, Digikey, Grainger, McMaster Carr, Amazon, Ebay and such. Most places are sold out or only have 1 or 2 in stock. The Automation Direct sensors linked above require a M12 plug which will evidently add another $10 or $15 to the cost of each…. AD is sold out of the wired version. It is all very frustrating.
Finally, do you think if I mounted a sensor perpendicular to my Z axis that the sensor would pick up the bearing?
Here is another picture:
So if anyone has any suggestions or advice it will be most welcome and appreciated. As always, Thanks.