Building Smart Scale, Modbus RTU (Serial) , Ignition

Projects Discussion and Showcase Home Automation
1

Hi,

So I want to build a Smart Scale that I can weigh my Hydroponic Lettuce/ Tomato's. I am also going to use same Smart Scale to track Water and Nutrient usage.

I eventually want to Visualize the Data in Ignition and use Ignition's Graphics, Historical Trends, DB. I picked Ignition because we use it at work figured I should use it at home for more experience(only 2hr trial, though)

HW:
Duemilanove or Leonardo(trying both)
HV711 board(ebay clone)
20x4 LCD display with YWRobot backpack
5 kg loadcell
Intel NUC running ESXi 6.7
SW:
Arduino IDE 1.8.3
Ignition 7.9.9
Serial Gateway Module(to get Modbus RTU Driver)
Oracle Express 11g
Windows 10 LTSB(in VM on ESXi)

Libraries:

HX711_ADC.h
Modbus.h
ModbusSerial.h
Wire.h
LiquidCrystal_I2C.h

I have some Rough Arduino code, that is mixture of Examples from the Various Libraries I have relied on.

When I run this code on an old Duemilanove it works but sometimes if my the Modbus RTU Driver on the Ignition Server connects too quick as it boots. The local LCD display hangs. Also each time Ignition connects to the Duemilanove, it reboots(something to do with DTR line).

So I bought a Leonardo from Microcenter. Moved the SDA and SCL over. It works, but only if there is a Modbus master(Ignition Server). Something in the code hangs, if there is not something to read the Modbus registers(weird?). Once I hit the Leonardo with QModbus or Ignition Modbus driver, scale works.

Atleast with the Leonardo board I can disconnect and reconnect Modbus RTU Server without rebooting the Leonardo, but I need to figure out why if there is no Modbus RTU server the sketch Hangs at

  lcd.print("Scale Booting Up");
   // Config Modbus Serial (port, speed, byte format) 
  mb.config(&Serial, 38400, SERIAL_8N1);

WeighScaleModbusTCP.ino (2.96 KB)

2

I have a feeling my problem is somehow related to this.
http://forum.arduino.cc/index.php?topic=143028.0
It appears people have modified the CDC.cpp file to remove some line state conditions(watching for DTR).

I attempted the comment out approach listed in post but no luck.

I might just go pick up an UNO and cut the AutoReset on Serial connection. I only bought the Leonardo because it doesn't autoreset on a serial connection.

My Ideal functionality is the Sketch Boots up when there is power to board. The Local LCD display should always display the weight from Loadcell. The Sketch should be in a State that it can output Modbus RTU Weight data if it USB Cable starts plugged in or even if USB cable is plugged in after a power up.

3

Gave up on the Leonardo. I bought an another UNO(didn't want to take the one doing Voltage Regulation on my Alternator). I cut the Reset Enable trace and I have my desired behavior. Now the Sketch does not restart when I make a Serial Connection.

If you are confused/curious about what you are actually cutting. read this. The Trace is the Jumper under the Solder Pad symbol on the Schematic.
http://forum.arduino.cc/index.php?topic=256096.0

The CrossRoads dude that explained the Solder Pad Trace has some really cool looking screw shields.