ITTSB.EU Blog Forum
ITTSB Blog Specific => ITTSB General Discussion => Topic started by: Kiriakos GR on September 15, 2025, 03:39:55 PM
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New replacement of rotary encoder and steps appear reversed
And or this question might also described as: Rotary Encoder stepping in wrong direction ?
Long story in sort, I was after to exchange / replace, the rotary encoder of one electronic circuit, this be Chinese development.
They are not any circuit schematics and or a parts list available.
I had to improvidence, and use as replacement my only one rotary encoder that I kept in stock.
My stock of rotary encoder with power switch, this is also unbranded, no part codes (5 pin).
My new part this replaced a damaged rotary encoder, and both parts has identical physical dimensions.
"Houston, we have a problem"
a) I get Rotary Encoder stepping in wrong direction (original part this was increasing at clockwise rotation), this new one decreasing at clockwise rotation.
b) Stepping issues, the new Rotary Encoder this send confusing signals at the micro controller, it works but the movement it should be performed in slow motion.
Thanks to ALPS Japan ( products documentation), I gained awareness, that the most important specification of a rotary encoder this is the selection of correct Number of pulse and of Number of detent ( positions ).
From the side of micro controller any developer he performs programing, so his circuit to recognize rotary encoder of specific Number of pulse at a full rotation.
In the year 2025, ALPS (Japan) products are nowhere to be found.
Two popular ALPS product codes comes with:
Number of detent 30 / Pulses 15
Number of detent 18 / Pulses 9
Within Mainland China
Replacement products they are presented as:
Rotary encoder 30 steps / Pulses 15
Rotary encoder 20 steps ....
Shaft diameter and length specifications, along actual dimensions.
In conclusion, wrong rotary encoder stepping this is the source of Evil.
In basic electronics we were educated so to think about polarity of electronic components.
Rotary encoder this is a component of Digital Control, and its not a stand-alone controller.
In my case, I know today that my circuit this require a Rotary encoder 30 steps / Pulses 15.
And that my stock of spare Rotary encoder, this is compatible for any project this requiring a 20 steps spare part.
"Houston, we solved the problem" ;D
https://www.mouser.com/catalog/specsheets/ec11-8098697.pdf (https://www.mouser.com/catalog/specsheets/ec11-8098697.pdf)