I have a project I'm currently working on and it has me stumped so I thought I'd come here for one last attempt.
Scope: To modify existing machine to work for the intended purpose or purchase.
Background: The company I work for were sold a linear weigher to reduce man power on a production line. It basically has 4 lanes that are fed from one hopper, you set the desired weight for each lane and it vibrates along untill the bucket is at the set weight. (Slows down nearer the target weight to avoid over weights).
We were sold this machine (Chinese imported rubbish) over a 18 months ago on a promise it will do what we want. Much politics and many meetings later it's agreed it won't. This is where I step in as an engineer that is always trying to find solutions.
Basically we do wet/sticky products this machine is designed for dry products it will not work so after a meeting we decided to see if we could convert it to augers instead of vibration to push the product down.
So we have contacted the actual manufacturers in China who don't really want to help fair enough I guess.
So it's up to me to try and here is a basic explanation of how it works and hopefully some one can say oh do this and it'll all be good.
The vibration PCB has an pic16fxxx MCU on it that outputs a signal to optocoupler that has a triac connected to it's other side and this controls a 110vac supply to a vibrator coil.
I have since learnt about triacs and that to control the power output you must change the firing angle etc etc.
Our plan was to somewhere from the MCU pin onward intercept the signal with an Arduino and find it's minimum signal (0% on the HMI) and maximum signal (100%) on the HMI and convert it to a usable output for a motor type as yet undecided. So 0% would be 0rpm 25% would be 25rmp etc etc.
Using and UNO I have tried a few things and haven't had any success. I've measured frequency (it stays at 50Hz regardless of percentage) I've measured duty cycle (stays at 6% regardless of percentage) I've tried analogue read (stays at 0 with a very occasional 1023).
My oscilloscope shows the same readings so I think the UNO is ok?
I can't think what else to look I've tried both triac side (with load) and MCU side by removing the optocoupler and connecting the Arduino GND and pin 7.
Any tiny bits of help would be very gratefully appreciated.
I can provide photos if required no code to post as it's only basic stuff but maybe that's what I'm doing wrong?