Question to power supply



  • Hi all,

    I am starting with an UniPi v1.1 and a Raspberry Pi B+.
    The installation of the evok software was sucessfull (using wget).

    However, I do not become a contact with the UniPi.
    The request http://PI_IP_ADRESS/rest/relay/1/value results in 500: Internal Server Error

    The GUI in the browser starts, but do also not show any inputs or outputs.

    I use two power supplies an jumper J1 is removed. The PSU of the UniPi has + in the center. Is this correct? I cannot find any information about the polarity. Maybe I bought the wrong PSU. Is there a status LED on the UniPi?
    Do you have any hints?

    Thanx



  • Hi all,

    I am starting with an UniPi v1.1 and a Raspberry Pi B+.
    The installation of the evok software was sucessfull (using wget).

    However, I do not become a contact with the UniPi.
    The request http://PI_IP_ADRESS/rest/relay/1/value results in 500: Internal Server Error

    The GUI in the browser starts, but do also not show any inputs or outputs.

    I use two power supplies an jumper J1 is removed. The PSU of the UniPi has + in the center. Is this correct? I cannot find any information about the polarity. Maybe I bought the wrong PSU. Is there a status LED on the UniPi?
    Do you have any hints?

    Thanx



  • Hello Holger,
    I've testet the PSU-connector @UniPi v1.1 and the pin in the center is + (at most devices it is +).
    Have you tested your system with only 1 PSU and J1 closed? This would be my first test. I think there are some Led on UniPi which will light up. Especially every relay has 1 Led if switched.
    There is a little problem if UniPi works with 5V and RPi has no voltage (see "SCL and SDA…"-Thread).
    with best regards
    iot



  • Hi iot

    thank you for the tip. I tested it but without sucess. The Pi starts again and putty works.
    But no reaction from the web GUI.

    Do I need some changes in the Pi configuration? After the installation SPI and I2C was disabled.

    best wishes
    Holger



  • OK, I solved it now.

    After a third installation , this time with the git, it works.
    The first and second time I used the master from wget.



  • Congratulations Holger! Why the wget doesn't work?

    Due to a missing router (on holiday trip) I can't go on with my RPi2 . So I`m looking to the Softwareoptions at the moment.
    What do you want to control with your RPi/UniPi? Which SW do you want to use? Sorry for questioning but the putty connection failed on first day (I guess missing DHCP on my laptop) and all the time only thinking about theory could be boring.
    We want to program a power controlled heat pump (with 0-10V analog output for P_el) and want to start with "Rex Control" or the new "Mervis". Because of many Parameters (6x temp., 2 mixer, 3x 0-10V analog out) we are not sure if this is the right way. What do you think?
    with best regards
    iot



  • Thank you iot
    First, I am a really bloody newbie with Raspberry Pi and Linux.

    I don´t know why it wasn´t working. The download and unzip was without problems. During the installation there was a message about a missing gcc but it ended with the message "evok installed successfully".
    The web Gui just showed the headlines, no buttoms.
    In the raspberry-config I activated SPI and I2C manually then the Web GUI showed the digital inputs and the analog output. Finally, I installed it again from github. Then it worked...

    My first objective is setup the UniPi as data logger also for a heating system. I want to monitor the heat storage with one-wire temperature sensors. Furthermore, the temperature, humidity and air speed in the ventilation system is the next objective ventilation. The air speed provides a 0-10 V output and I think that will not be a huge task.
    The temperature sensors in the ventilation uses RS485 with MODBUS... that will be a challange. Do you have any tips?
    I plan to save the data on a SSD and on a NAS drive.

    Maybe, the second objective is using the system for controlling the heat pump, electric heater and pellet oven. The Pi will recieve a command from a control central and have to translate it and activate the systems. Maybe with the relays or by another bus command. I don´t know it yet.

    As far as I know, the control of a heat pump is sometimes tricky. You have to consider some minimal operation times, cooling-down phases and temperature limits to avoid stress and damage to the heat pump.
    The 6 temp sensors should not be a problem, for the mixers and 10v-out you probably need a extension, isn´t it?

    Best wishes
    Holger



  • Hi Holger, thanks for detailed information.
    I'm a newbie on RPi and Linux too.There is some expierience in programming microcontrollers with Bascom. A heat control for an waterbased oven is my top program (5x 1-wire Temp.sensor, 20x4 LCD by I2C, 0-5V input from flow sensor for volume measure and heatpower calculation, 0-5V out for speed control of a Laing-DC-Pump (<10W)).

    Because the RPi often failed with the SD-card I would better prefer a board with Sata like Cubieboard or Banana Pi. Unfortunately the most projects are based on Raspberry and I have to learn software . Thats why I ordered the new Kickstarter PiDrive-PCB now which allows the RPi-Linux to play on a SSD (only for booting the SD-card will be used.). It's not the cheapest and fastest solution but gives option to use RPi much saver and it's possible to use the RPi-software. Also a small UPS based on an easyacc-Powerbank (PB) will be installed. http://raspi-ups.appspot.com/de/index.jsp
    The missing restart after a very long power loss could be managed by a small Attiny board betwen 5V_in and PB. If power comes up it could switch the PB-button. Unfortunately you have to open the PB. Because a power loss of more than 2h is very unusual in Germany this is only a future feature.

    Controlling a heatpump by own software seems to be the strong way. Fortunately UniPi delivers most of the hardware. You are right - I bought the UniPi-extension with 4x 0-10V analog output too (I2C based). Because of the more overview we are willing to test the visual programming by Rex-Software. We hope an advantage will be the figures so documantation of program could be minimised. The new upcoming MERVIS looks more visual than focusing on program-problems which are more essential for heatpump.
    What about python? Which software do you want to use for first and second step of your project?

    with best regards
    iot