Forgot to say, added in the Files section ref RELS data.

See schematic for installing.

Also you may need the Adafruit files loaded in the Arduino sketch.

I have attached the ZIP?s

Hope this helps

Cheers

John

On Sat, 10 Feb 2024 at 05:47, John Lindo via <bechetboat=[email protected]> wrote:

I have added an Arduino file Tach.ino?
I hope this helps?
This is used in my RELS. Also see the schematics for wiring in.
Cheers
--
John

--
John

You will need to use interrupts. One per phase. Looks like an Arduino lib already exists.

On Fri, Feb 9, 2024, 3:40?PM Ralph Hulslander <rhulslander@...> wrote:

I need some 4 pin encoder code for a 1000 line encoder.

Most of the code for RPM I have found online does not work.

I do have some Arduino code that "almost" works, but it is not accurate.

Ralph

On Fri, Feb 9, 2024 at 3:47?PM Jerry Trantow <jerry.trantow@...> wrote:

I have implemented several tachometers in software but haven't implemented an arduino tach. I have installed several of the $15-$20 tach (RC-41) modules which are very simple to install if you just need a quick RPM display. I've been using one on my lathe spindle for a few years. I recently added a feedback loop for the spindle VFD and noticed the module speed is off by maybe 10-20% under 100RPM but gets better at higher speeds.

Coding a tachometer can be a bit tricky if you require accuracy. It all depends on how many pulses you get per revolution and how fast it's spinning. One method is to count the period between tach pulses to calculate frequency/RPM. You use a timer interrupt that captures a high?resolution timer on the pulse. You need a little bit of logic to detect slow speeds which can wrap your timer. Usually you will low-pass filter these values to smooth out the RPM value. Some automotive tachometers/software use a multiple teeth system with?a missing tooth to provide multiple position and velocity estimates per revolution.

My lathe uses a 240 pulse per revolution disk (60 teeth with quadrature pulses) for threading. LinuxCNC supports missing tooth encoders so I could remove a tooth and get absolute positioning (within 1.5 degrees) The software provides an instantaneous RPM that I low pass filter before display so it doesn't jump around.

The lathe also has the RC-41 display with a 1 pulse per rev sensor that I used to set the spindle RPM when I was using a potentiometer to control the VFD.

Recently, I removed the pot and control the VFD with linuxCNC. This is when I noticed the RC-41 wasn't very accurate <100RPM.

On Fri, Feb 9, 2024 at 1:57?PM mike allen <animal@...> wrote:

hey folks have any of ya made a tachometer using a Arduino ? I tried
some I found online but most of them seem to have something wrong with
the code? I'm not smart enough in the Arduino world to decipher the code
. What are you folks using ? I don't want to buy just a tachometer? from
China . I need to get one working in the Arduino platform for part of a
project I've got going .

thanks

animal

--
Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer

Hello, fellow machinists,

I worked in the design input and implementation of rotary shaft encoders manufactured by my employer on and off for over 30 years. I haven't noticed anyone mentioning the incremental encoder limitations, which can cause serious issues and problems. When some of the commenters say that their code "almost works", it sounds like an encoder problem.

First, and most often the issue, is the maximum encoder frequency, usually specified in kHz. This is the maximum rate at which the encoder can generate pulses. Exceed this frequency and the encoder may become unreliable and may drop pulses, resulting in inaccurate readings.

Let's say you have a 1200 PPR (pulse per revolution, sometimes called "lines) encoder. Let's assume a maximum spindle speed of 2400 RPM, and that you are mechanically driving the encoder 1:3. I.E., one turn of the spindle causes 3 turns of the encoder. 1200 PPR X 2400 RPM / 60 seconds/minute X 3 = 144 kHz. Under these conditions, an encoder with less than a 144 kHz frequency response may function unreliably or not at all when its conditions are exceeded. If you had, for example, a 50 kHz encoder, in our example above, it would generate pulses reliably only up to 833 RPM. The first Chinese encoders I purchased for a machining project were only rated at 10 kHz, so I would encourage you to check your conditions and make sure that the encoder you purchase meets the need of your project.

Second, encoders have a maximum rated mechanical speed, specified in RPM. Make sure that you take into account and gear/belt ratio impacts. In our example, the maximum spindle speed is 2400 RPM, but the encoder is turning 3x faster than the spindle. So, the encoder is turning 7200 RPM. The rule here is simply don't exceed the maximum rated encoder speed.

The third issue is more subtle and often overlooked. The relatively delicate encoder spindle is supported by bearings. These bearings have maximum radial and axial load ratings. Exceeding these loads will decrease the life of the encoder, in some cases significantly. If you are driving the encoder axially directly from another shaft of similar size, just be sure to use an instrument-type flexible coupling and things should be fine. If driving with a timing belt, avoid putting any more tension on the belt than you have to.

I hope this info may be useful to you.
--
Regards,

Charlie
New Jersey, USA

NOTE: No trees were injured in the sending of this message,

but a large number of electrons were terribly inconvenienced.