08/22/2019 at 19:35 •
I used MICRIO MPU for my Load Cell - Modbus interface test.
I did ADC and Load Cell noise test.
Left to right: MICRIO MPU, DI8 input module, Load Cell - Modbus interface, 0.2 ton Load Cell.
Around 120 ADC counts of noise. Full ADC resolution is 24bit = 2^24 = 16,777,216.
It's around 17 noise-free bits.
0.2 ton load cell has range 400 kg (200kg for compression and 200kg for tension).
For 400 kg range, with 17bit resolution, I can achieve an accuracy around 3 grams.
Not so bad)
08/14/2019 at 19:51 •
I thought to write some description about my MODBUS MCU, but I think the video is better. So I did it (I don't speak English so good, but I can write subtitles).
Features in my Modbus slave controller:
- RS485 galvanic isolation (up to 560 Viorm).
- Work with modules DI8 (8 universal digital inputs) DO8 (8 digital outputs 3-28V) , DIO4 (4 universal universal digital inputs + digital outputs 3-28V), RLY4 (4 relay outputs), SSR4 (4 solid state relay with temperature protection).
- GPIOs can act as inputs or as outputs without reprogramming MCU.
- Ability to save outputs initial state.
- The best feature is the WATCHDOG implementation. If your main controller stuck, my MODBUS MCU return outputs in the initial state.
I also have RS485 radio extender and MODBUS RADIO module for wireless link up to 3 km. I will write about it later. Stay tuned)
08/07/2019 at 16:57 •
Small video about very basic functionality of my system is done.
Unfortunately I'm not so good English speaker, so I added English subtitles.
08/06/2019 at 14:10 •
I've just received the new PCB's:
MICRIO MPU rev. 1.4 (added some fuses and minor tracing changes)
MICRIO TOP BOARD rev. 1.2 (changed SMA connector footprint to universal, added jumpers for the wireless modules)
MICRIO I-BOARD rev. 1.2 (minor changes in connector placement)
08/01/2019 at 12:29 •
Now I have 3 different types of MICRIO MPU top covers.
Clear acrylic, IR acrylic, Solid plastic.
07/31/2019 at 20:57 •
The first test with for the MICRIO PI-FACE with connected Raspberry PI3 B+ done. I've had some challenges with the UART settings(I use AMA0 UART for RS485 communications), but happily that all in the past. PSU works fine, the temperature of IC, inductor and diode do not exceed 50 degrees Celsius, so I think my device can work with 90 degrees Celsius outside temperature (thanks to bulletproof TI TPS5430). Also, I checked the UPS and Power Manager functionality. The next step is to test the surge protection and EMI.