ENCODER BUG? Fysetc 12864 G32 MBL screen Builtin function

dc42

@leckietech it's a while since I bought encoders, but I remember looking at the specifications and choosing Bourns in preference to Alps.

alankilian

@leckietech I haven't purchased encoders for a while, but I think most enything from DigiKey should be OK.

It's interesting that this one shows a recommended filter arrangement on page 2
https://www.digikey.com/en/datasheets/cuiinc/cui-inc-acz11

Also, on page 2, they imply that the switches are going to bounce for up to 5 milliseconds when they change state. I didn't do the math, but with 20 pulses-per-rev I don't think you'll have a problem with that unless you try to spin the encoder REAL fast. (Probably you should do the math)

For less then US$6 each, I would get one or a few when you next order from DigiKey.

Topher

@dc42 thanks for the tip - ive found one i think will work. Ill order it and report back!

@alankilian Thanks for the suggestion. I was looking at this one here:

https://www.digikey.ca/en/products/detail/bourns-inc/PEC11R-4015K-S0024/4699187?s=N4IgTCBcDaIAoFEDCBGFAlAtAFgAwoFYBpTAZV1zGxAF0BfIA

The measurements check out and it has only 2ms bounce time @ 18rpm. Seems ok to me. I noticed they suggested the same debounce filter, too. There is some noise on mine but I am certainly missing some pulses as you so kindly confirmed. Ill order a few. Ive got 60 of these screens so its kinda a bummer I have to repair all of them...

Topher

@dc42 Im running a few of these on Duet 2 wifi, I noticed the M300 only triggers a 0 or 1 state based on P*** whereas the Duet 3 actually oscillates a tone based on the S***? Is there a way to address this or should I replace it with a piezo speaker that will make a constant tone with 5 volts?

Topher

@alankilian @dc42 Sorry guys. looks like I made a mistake testing and must have been moving the leads too much while turning the encoder so I put some pins right into the header at the duet board. It's not the encoder after all. Here is the scope while turning the encoder left slow then right fast. every pulse is accounted for. during this time I had selected 521 baby-stepping on the 12864 display and I can confirm, it is still giving me erratic responses even though these are clean pulses.

Topher

@dc42 Here is another example in my home menu. If the knob is turned so it lands between bumps in the encoder, it will actually somewhat oddly select 2 items at once. During this time the scope is flat-lined, so I can 100% confirm there is no noise with the switch in that position.

dc42

@leckietech those are still not normal encoder pulses. A normal encoder produces pulses with a mark:space ratio of around 1:1 and the two signals are 90deg out of phase. Those pulses are much shorter and overlap only slightly, which means the encoder needs to be polled much faster in order to detect all the states that it goes through.

My guess is that the combination of pulses that only overlap slightly coupled and a known issue with inefficiency of how the ST7567 display is updated are causing RRF to miss some state changes. The display update issue is scheduled to be fixed in RRF 3.4.

Topher

@dc42 Ok, well I already ordered a few encoders from bourns. Ill try that out and report back.

Topher

@dc42 I just finished installing the new encoder. annnnnnd... It works perfectly! The new bourns encoders use 4 pulses and found it corrects the overlap issue I pointed out as well with the Fysetc encoder. When you're right, you're right, thanks. You've saved me a lot of trouble.

dc42

@leckietech I'm glad that solved it. I'm surprised that nobody else has reported a similar issue.

Topher

@dc42 said in ENCODER BUG? Fysetc 12864 G32 MBL screen Builtin function:

@leckietech I'm glad that solved it. I'm surprised that nobody else has reported a similar issue.

With duet having such a slick web interface, its possible others may not be using this option to the extent I am for our farm with a large number of printers. Afterall, the equipped encoder from Fysetc is fully functional in the menus, the encoder just struggles with controlling Z steps which is why I thought it might have been firmware related. Its a fantastic inexpensive option that is very effective and flexible and I hope more features will be brought to supporting this device!

oliof

Could also be that there's just a bad batch of encoders that you got because you bought plenty at the same time. And hobbyists may just give up and buy another display with an encoder that works ...

dc42

@oliof yes I think it' a bad encoder. Not impossible to read those short pulses, but not handled by the code in RRF when there is movement going on.

Topher

@oliof I have 60 of them, a pretty big batch of bad encoders!

dc42

@leckietech if you send one of them to me I can take a closer look.

Topher

@dc42 I can do that, if you can PM me a shipping address, I will send a few of the encoders Ive changed out, tomorrow. Thanks!

dc42

@leckietech I would prefer to receive a complete unit with dodgy encoder too. My own Mini 12864 display does not have this problem. I will PM my shipping address.