Looking forward to moderating your discussions.

Regards,
Tomas @ REXYGEN Team

In the REXduino slave, this value appears as the byte "microseconds" entering the function commandU in REXduino_commands.ino. There you can process the value and use it to control your heater.

You can also change the data which is returned to the REXduino master. By default, uptime in milliseconds (userSend!=0) or microseconds (userSend==0) is returned and this data appears at the userRecv output of the master block in REXYGEN algorithm.

Hope this answers your question.

Jaroslav

Thanks for posting your findings and thanks for your interest in REXduino!

Jaroslav

we don't have any specific document about advantages / disadvantages of using REXduino.
This is list of dis/advantages I can think of now:

Advantages:

• analog inputs (e.g. 17x using Arduino MEGA compared to absence of analog inputs on Raspberry PI)

• more GPIOs (up to 54 GPIO using Arduino MEGA compared to standart 17 GPIO on Raspberry PI)

Disadvantages:

• slower sample rate (up to 20 ms in general or up to 10 ms with limited IOs in operation)

• additional hardware required (Arduino)

If you require any further information, let me know.

Regards, Tomas

The same probably holds for Controllino but I have no personal experience.

We were able to get the "Slave" file/code loaded on our Arduino Uno once we defined all the errors. We were then able to the get the blink example you provided to work. We are now just trying to familiarize ourselves with the function blocks. For now we are to just simulating some analog inputs and have basic ouputs. 
I'll keep you posted on our progress.

So let's get this sorted out. First plug in only one Arduino and type

ls /dev/ttyACM*

You should get /dev/ttyACM0. Use it in the following command.

Then run this command

udevadm info -a -n /dev/ttyACM0 | less | grep KERNELS

You will get something like:

    KERNELS=="1-1.2:1.0"
    KERNELS=="1-1.2"
    KERNELS=="1-1"
    KERNELS=="usb1"
    KERNELS=="20980000.usb"
    KERNELS=="soc"
    KERNELS=="platform"

Write down the identifier from the first line ("1-1.2:1.0"). This identifies the USB port in your system.

Repeat the above with the Arduino connected to another USB port(s) and find the USB port identifiers. I have "1-1.2:1.0" and "1-1.3:1.0".

Now create a file named /etc/udev/rules.d/99-arduino.rules, e.g.

sudo nano /etc/udev/rules.d/99-arduino.rules

Put the following in:

SUBSYSTEM=="tty", KERNEL=="ttyACM*", KERNELS=="1-1.2:1.0", SYMLINK+="arduino_one"
SUBSYSTEM=="tty", KERNEL=="ttyACM*", KERNELS=="1-1.3:1.0", SYMLINK+="arduino_two"

Add more lines if you plan to use more than two Arduinos. Save and exit.

This means that whenever a ttyACM* device is plugged into the USB port "1-1.2:1.0", a symbolic device /dev/arduino_one is created. And that whenever a ttyACM* device is plugged into the USB port "1-1.3:1.0", a symbolic device /dev/arduino_two is created.

Now disconnect your Arduino and run

sudo /etc/init.d/udev reload

Afterwards connect your Arduinos to the appropriate USB ports and you should be able to use /dev/arduino_one and /dev/arduino_two in the REXduino function blocks. Unless you mismatch the USB ports, you'll always know which Arduino you are referring to.

Note the reversed order.

Numbering of the modes is the following:
0: Not connected
1: Not connected
2: Digital output
3: Digital input
4: Digital input with internal pull-up
5: Analog output (PWM)
6: Analog input
7: 1-Wire temperature
8: Counter (only pins 2 and 3)
9: Encoder A (only pins 2 and 3)
A: Counter DIR / Encoder B (only pins 4 and 5, pin pairs are 2+4 and 3+5)

As a side note, the PIDU block calculates appropriate output even if the input is above setpoint. Why do you want to implement the IF condition?

REXduino_master.stl
X_UNO_PIDloop_task.mdl
X_UNO_PIDloop_exec.mdl

[159084.594626] usb 1-1.2: new full-speed USB device number 4 using dwc_otg
[159084.710558] usb 1-1.2: New USB device found, idVendor=2341, idProduct=0001
[159084.710597] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=220
[159084.710614] usb 1-1.2: Product: Arduino Uno
[159084.710628] usb 1-1.2: Manufacturer: Arduino (www.arduino.cc)
[159084.710642] usb 1-1.2: SerialNumber: 64935343733351F060E0
[159084.773590] cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device
[159084.778277] usbcore: registered new interface driver cdc_acm
[159084.778312] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters

From which you can see that your Arduino is /dev/ttyACM0.

The Arduinos with FTDI USB chip typically appear as /dev/ttyUSB0.

Another option is to type ls /dev/tty* before and after plugging the Arduino in and find the new device in the list. That's your Arduino.