Connecting a 5V sensor to KStep

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georgep
Posts: 6
Joined: Sat Apr 08, 2023 11:39 pm

Connecting a 5V sensor to KStep

Post by georgep » Thu May 18, 2023 4:10 pm

I have a rotary turntable with integrated hall effect sensor. The sensor has a digital output which drops from 5V to Low when the home position is detected.
The sensor circuit is partially buried so I'm not sure of the components and specifically the output drive.

Can someone please recommend a safe and pragmatic way to interface this 5V digital signal to KStep?

Some ideas I had:
* Transistor to switch the 12V Optically isolated Inputs
* Level shifter between the 5V sensor and the 12V Optically isolated Inputs
* Just use one of the 5V tolerant GPIO on the KFLOP (but with a current limiting resistor?)

Thanks, George

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TomKerekes
Posts: 2540
Joined: Mon Dec 04, 2017 1:49 am

Re: Connecting a 5V sensor to KStep

Post by TomKerekes » Fri May 19, 2023 3:47 am

H George,

An NPN transistor should work. You might also want a base resistor to limit base current.

This module from Winford should work it provides opto-isolation and very flexible on level shifting. Its a bit of overkill and is not very fast (Bandwidth 1KHz) but KStep inputs are relatively slow also (Update every 1.44ms).

Its probably not a good idea to run long wires from the machine directly to KFLOP inputs. Especially if the Hall outputs are not isolated.

If the Winford module was used it could provide the isolation and the output can operate at 3.3V to connect to a KFLOP 3.3V input.
Regards,

Tom Kerekes
Dynomotion, Inc.

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