Valden: Remote Display v1.x

This device allows you to control the Valden Heat Pump via remote display. Display can be used with a signal cable up to a few hundred meters long. As well as the controller this display is an also open product with available gerber and source code.

Further details, appendices, fine-tuning options, illustrations, abbreviations, and so on you can find in the permanent repository: https://github.com/openhp/Display.

Specs

- 12V 0.5A DC power supply,

- build-in RTC,

- Day/Night temperature set,

- LCD 16x02,

- RS485 connection to the Heat Pump,

- secondary RS485 connection to integrate with external systems ( [example here](https://github.com/openhp/HP-integration-example/) ),

- JSON,

- MODBUS.

Changelog and history

- 2019-2021: prototyping, PCB development and redesigns; background firmware development,

- Dec 2020: Service display software fork created,

- Mar 2021: documentation,

- Aug 2021: public access and active testing stages.

Get your own PCB copy. Assembly.

- download PCB Gerber file here or get your own copy,

- order electronic components, see BOM (Bill Of Materials) appendix below,

- solder electronic components, assembly instructions here

Firmware upload

This process is the same as for other Arduinos:

- connect USB-> UART converter,

- start Arduino IDE,

- open the firmware file

- select board and MCU in the Tools menu (hint: we are using "mini" board with 328p MCU),

- press the "Upload" button in the interface and "Reset" on the Arduino.

For arduinos with an old bootloader you need to update it. (Tools -> Burn Bootloader).

For successful compilation, you must have "DS3231", "LiquidCrystal" and "SoftwareSerial" libraries installed (see Tools -> Manage Libraries).

Note that SoftwareSerial library must be downloaded from the "Valden Remote Display" GitHub repository and located at the same directory as "Remote Display" source. This library is slightly modified.

If there is no text on screen: use i2c scanner sketch (File -> Examples -> Wire -> i2c_scanner) to find 1602 address, typical 0x3f, 0x27. Then change "i2c_DisplayAddr" in this firmware to yours.

If address Ok: tune 1602 contrast (blue variable resistor).

A manual configuration is not required, your display will work as in the pictures below after connecting to the heat pump.

Wiring and installation

Wiring is very simple:

- connect "internal" RS485 terminal through a wire of the desired length to the [Heat Pump Controller](https://github.com/openhp/HeatPumpController/). Note that A is connected to A, B to B and GND to GND,

- connect 12V, you can get it from your [Heat Pump Controller](https://github.com/openhp/HeatPumpController/), or from another 12V power supply unit.

- if used, connect "external" RS485 terminal to your computer, Raspberry, or server (communication example here)

Usage

An end user does not want to know much about refrigerants, evaporation, cycles and so on, so this display designed as simple as possible.

After powering on, you will see the following main screen:

Here you'll see:

- current time,

- "d:" Day setpoint temperature,

- "n:" Night setpoint temperature.

The second string is:

- "W:" Water (tank) temperature (Ts1 sensor),

- "F:" Floor, if a "warm floor" scheme used (Thi sensor).

And the last value is a current state, one of the followings

- "Run" the heat pump is powered on,

- "Stop" heat pump is in power-saving mode,

- "Chkg" the heat pump is checking target temperature (then it will go into power save mode or switched on, if temperature is lower than setpoint)

Press the "Left" and "Right" buttons together to enter the time configuration mode.

Now you can set the time. The "Middle" button switches to the next option.

To set "day" or "night" temperature return to the main screen and press "Middle" button. Then use "left" and "right" buttons to change setpoint value.

Further details, appendices, fine-tuning options, illustrations, abbreviations, and so on you can find in the permanent repository: https://github.com/openhp/HeatPumpController/.

Author

gonzho АТ web.de (c) 2018-2021; All rights reserved

License

(c) 2018-2021 D.A.A. All rights reserved; gonzho AT web.de; https://github.com/openhp/Display.

Text, media and other materials licensed under CC-BY-SA License v4.0.

Attribution: You must clearly attribute Valden Heat Pump Controller (https://github.com/openhp/Display) original work in any derivative works.

Share and Share Alike: If you make modifications or additions to the content you re-use, you must license them under the CC-BY-SA License v4.0 or later.

Indicate changes: If you make modifications or additions, you must indicate in a reasonable fashion that the original work has been modified.

You are free: to share and adapt the material for any purpose, even commercially, as long as you follow the license terms.

The firmware source code licensed under GPLv3.

This product is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

For third-party libraries licenses used in this product please refer to those libraries.