Limit switches! What is the most accurate?


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Thread: Limit switches! What is the most accurate?

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    Gold Member LeeWay's Avatar
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    Default Limit switches! What is the most accurate?

    As in the title, I am looking for the most accurate switch types. Certainly safety related. The ones I am using on various machines are doing the job with the accuracy I need, however better switches are always a plus, but sometimes budget killers.
    Lets have some suggestions and discuss those.

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    Lee


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    Default Re: Limit switches! What is the most accurate?

    Mechanical types have their limitations, proximity type can be purchased with different sensing ranges. What type are you using?



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    Default Re: Limit switches! What is the most accurate?

    Limit switches primary function is to ensure the machine does not crash if it exceeds these.

    Normally accuracy is not required, unless you are also using these as your homing sensors as well, they that pays to be accurate.

    Optical sensors tend to be the fastest, and are extremely repeatable.

    Lot of 3X Emron EE SX673 Optical Sensor Switch with Omron EE 1006 Pigtails | eBay

    These type sensors typically have three or four wires. They are essentially an OPTO coupler that is using a flag in between the transmitter and receiver.

    You could configure you unit to keep the mechanical limit switches, and add optical homing sensors or do both with the OPTOs.

    Russ



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    Default Re: Limit switches! What is the most accurate?

    Yeah, separate the safety functions and the Home sensing functions. They are very different.
    A genuine UL Safety switch is designed to open come what may when it is triggered. That may mean a big push-rod physically shoving the contacts apart.
    That is nothing like sensing a zero position.

    Cheers
    Roger



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    Gold Member LeeWay's Avatar
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    Default Re: Limit switches! What is the most accurate?

    I use both mechanical and proximity switches on various machines. They all work well for safety. Home positioning is probably the target I was after.Mine do home well because it is not that critical on anything but the Tormach lathe. It does a pretty good job too with mechanical switches. It repeats well. At least within tolerances that work for us. Just curious what might be more accurate than those in the future if I wanted to be precise.

    Lee


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    Default Re: Limit switches! What is the most accurate?

    I use non contact proximity switches on my mill and checked the repeatability since they are also my home switches. They repeat to within 0.0002".



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    Gold Member LeeWay's Avatar
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    Default Re: Limit switches! What is the most accurate?

    I have those on my mill too.
    I have not actually measured what the mechanical switches have for repeatability yet.
    I guess that would be a good place to start.

    Lee


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Limit switches! What is the most accurate?

Limit switches! What is the most accurate?