Display

Valden: Remote Display v1.x

<b> 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.</b> As well as the controller this display is an also open product with available gerber and source code.<br><br>

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 ),
• 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 there,
• order electronic components, see BOM (Bill Of Materials) appendix below,
• solder electronic components, assembly instructions here<br> <img src="./m_d_assembly_final_3.jpg" width="500"><br><br>

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).<br> For successful compilation, you must have "DS3231", "LiquidCrystal" and "SoftwareSerial" libraries installed (see Tools -> Manage Libraries).<br> 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.<br> 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.<br> If address Ok: tune 1602 contrast (blue variable resistor).<br> A manual configuration is not required, your display will work as in the pictures below after connecting to the heat pump.<br><br>

Wiring and installation

Wiring is very simple:<br>

• connect "internal" RS485 terminal through a wire of the desired length to the Heat Pump Controller. 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, or from another 12V power supply unit.<br> <img src="./m_d_wiring.jpg" width="500"><br>
• if used, connect "external" RS485 terminal to your computer, Raspberry, or server (communication example here).<br><br>

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.<br><br>

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

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)

<br><br> Press the "Left" and "Right" buttons together to enter the time configuration mode.<br> Now you can set the time. The "Middle" button switches to the next option.<br>

<br><br>

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.<br>

<br><br>

Appendix A: bill of materials

| Part | Quantity | | ------------- | ------------- | | 1206 Resistors: || | 100 | 2 | | 120 | 2 | | 1K | 4 | | 10K | 9 | | 100K | 4 | | 1206 Caps: || | 0.01uF | 4 | | 0.1uF | 9 | | 1uF | 1 | | 10uF | 10 | | KF124 terminals: || | KF124-3.81-3P | 2 | | KF124-3.81-2P | 1 | | SOP(SOIC) ICs: || | DS3231M (SOIC-16) | 1 | | ADM2587EBRWZ (SOIC-20) | 2 | | Others: | |
| MMBT2222A (SOT-23-3) | 1 | | LM7805 (TO-220) | 1 | | 1N4148W (SOD-123) | 1 | | 0.22F 11.2x6.5 (supercap) | 1 | | 10nF HV-9.0x3.0 (blue disc 2kV HV cap) | 2 | | KLS7-TS6601-13.0-180 (13 mm tact button) | 3 | | 2.54_pins_x40_female | 1 | | 2.54_pins_x4 | 1 | | BUZZER-R9.0-2P-4.0 | 1 | | ARDUINO PRO MINI | 1 | | 1602 display with i2c | 1 | | 1602 Plastic case | 1 |

License

© 2018-2021 D.A.A. All rights reserved; gonzho AT web.de; https://github.com/openhp/Display/.<br>

Text, media and other materials licensed under CC-BY-SA License v4.0.<br> _{Attribution: You must clearly attribute Valden Remote Display (https://github.com/openhp/Display/) original work in any derivative works.<br> 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.<br> Indicate changes: If you make modifications or additions, you must indicate in a reasonable fashion that the original work has been modified.<br> You are free: to share and adapt the material for any purpose, even commercially, as long as you follow the license terms.}<br>

The firmware source code licensed under GPLv3. <br> _{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.}<br>

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

Author

<br> gonzho АТ web.de (c) 2018-2021<br>