AVAILABLE IN TWO VERSIONS: DomBus protocol and Modbus protocol!
Creasol DomBus31 is a din-rail relay module, 115x90x40mm, with 8 relays outputs. 6 relays are SPST (Normally Open outputs) with 250V 5A max capability, and 2 relays are SPDT (both Normally Open and Normally Closed outputs) with 10A capability. High efficiency module, with very low power consumption, only 600mW with all relays ON.

The English language page contains the updated information
As other DomBus devices, DomBus31 provides excellent performance in terms of power optimization: with all 8 relays active (the worst case), the power consumption is only 600mW! As a comparison, KMTronic 8 relays module consumes 12W, Denkovi 8 relays board consumes about 3W, Sonoff Dual R2 consumes 2W with only 2 relays enabled.

It's available with two firmware types: DomBus (proprietary protocol with enhanced features) for Domoticz controller, and Modbus RTU (standard protocol working with almost any home automation system). Check below for a detailed comparison between the two protocols.
It uses a RS485 industrial-grade serial bus, using a common shielded cable with 4 wires: 2 for 12/24V power supply, and 2 for data at 115200bps 8,n,1 (or other speed/parity in case of Modbus RTU).

It supports two different protocols (at puchase time, select the needed protocol!):

• DomBus protocol, that is supported by Domoticz home automation controller, is a reliable multi-master protocol that permits to manage dozens of modules and get status from a module as soon as it changes. Also it includes the so-called DCMD commands that, similarly to KNX, are transmitted between DomBus modules in the same bus to activate outputs, scenes and groups in case of events without needing for the intervention of the home automation controller, useful solution to get a home automation system working even in case of domotic controller fault. Check below for an explanation about DCMD.
  The Creasol DomBus plugin have to be installed in Domoticz, using the Python Plugin Manager or downloading the software from GitHub (see the section below).
• Modbus RTU protocol, widely used in industrial and home automation systems, is supported by almost any domotic controller like Home Assistant, OpenHAB, IObroker, Node-RED, ...
  Modbus is a master-slave protocol that permits to activate and deactivate a single relay or a group of relays by a single command. Also, it's possible to specify, for each relay, the ON time from 31.5ms to 1500 days, so the relay automatically switches OFF after the selected time.

Confused about the two versions? If you use Domoticz, DomBus version is much better because includes enhanced features like DCMD and autodiscovery.  For other building automations, Modbus version should be chosen because compatible with almost everything.
Ask for support on Telegram group https://t.me/DomBus

The RS485 serial bus is the ideal solution to get:

• easy wiring and connection: use a common thin alarm cable within 4 wires, 2x0.5mm² wires for 12V power supply, and 2x0.22mm² wires for data. This is much easier and better than ethernet UTP/STP connections.
• robustness differential signalling permits to connect about 30 modules with more than 200m total distance. Modules can be connected together using a mix of linear/star bus topology.
• very low power consumption: each module is supplied at 12V and has inside an high efficiency switching mode converter to minimize the power comsumption.
• power outage tolerant: using a 13.6V power supply with lead acid battery it's possible to supply domotic network, IPCams, NVR, switches, routers, so the system keeps working even in case of power cut-out.
• no RF pollution, no batteries to change
  

For large building, to improve the bus reliability, it's possible to make more than 1 bus so in case of fault, only the bus with fault stops working.

Features

• 6 relay outputs, SPST (normally open contact on screw terminal block) with 250Vac/30Vdc 5A contact (max 30Vdc in case of DC load, 250Vac in case of AC load).
• 2 relay outputs, SPDT (normally open and normally closed contacts on screw terminal block) with 250V 10A contacts.
• Relays are divided in 3 blocks, each block respects the creepage distance from other blocks. Do not mix high and low voltage signals inside the same block!
• 8-35Vdc power supply (internally regulated by a switching mode power supply circuitry that minimize power consumption and dissipation).
• low power consumption: 0.75mA @12V (9mW) stand-by current with all relays OFF, and 50mA @12V (600mW) with all relays ON.
• 115200 bps RS485 bus (max length: 1km), 8 bit data, no parity, 1 stop bit. Bitrate and parity may be changed in the Modbus version.
• To do a factory reset, remove power supply to the module, short the JP jumper on the PCB (with a tin ball), and power on again: a short flash on LED red will be emitted.
• DCMD supports (DomBus firmware only): this is a feature (described below) that permits to get easy automations without writing a line of code, and command exchanged between DomBus modules even in case that domotic controller is stopped. For example configuring a pushbutton input port as
  DCMD(Pulse)=11.3:Toggle, DCMD(Pulse1)=0.7:Toggle, DCMD(Pulse2)=0.8:On
  it's possible:
  * with a short 0.5s pulse, toggles on/off port #3 output of DomBus module #11
  * with a 1s pulse, toggle on/off a group of switches on the controller
  * with a 2s long pulse, activate a scene that, for example, disable all lights/loads and activate the alarm system (useful when leaving the building).

Warnings

• Relays are divided in 3 blocks: do not mix high voltage (230V) loads and low voltage (5/12/24V) loads on the same terminal block!
• Do not use capacitive loads with high inrush current (bad power supplies, ballasts, ...) otherwise the relay contact may weld.
• Use a 4 wires shielded cable for the bus, using two lines to send power supply (12-14Vdc) protected by a fuse.
• To reduce noise and reflections on the bus, enable the termination resistor (shorting Rbus PCB jumper) on the two furthest ends of the bus.

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DomBus31 DomBus capabilities (for the DomBus firmware version)

Default address: 0xff31

(1): can be used as BLIND output, to open a blind/curtain, but only the previous port can be configured in Domoticz as OUT_BLIND because, when configured as OUT_BLIND, DomBus device automatically configure the next port to drive a relay in open direction.

DomBus31 Modbus RTU capabilities (for the Modbus version)

At power-on, the module shows on red LED the current Modbus slave address (register address=8192) in decimal format, on green LED the serial baudrate (reg. 8193), and finally on red LED the serial parity (reg. 8194).
If a value is zero, a long flash is emitted.

For example, if reg(8192)=54, reg(8193)=4, reg(8194)=0, at power the following led flashes will be shown:
5 red flashes, pause, 4 red flashes (slave address=54), pause, 4 green flashes (reg(8193)=4 => baudrate=9600bps), pause, 1 long red flash (reg(8194)=0 => parity=None).

Device will be operative only after showing the power-on modbus parameters led flashing: then module will accept commands by Modbus RTU, and periodically shows output status for all ports, from 1 to max port: green flash means that port status is Off, red flash means that port is On.

Default slave address: 49 (0x31)

It's possible to activate one or more outputs for a certain amount of time (monostable/timer output) as indicated in the table. The parameter corresponding to the needed time can be computed using the following rules:

From 0 to 60s => 31.25ms resolution 1=31.25ms, 1920=60s => value=time_in_milliseconds/31.5
From 1m to 1h with 1s resolution 1921=61s, 3540+1920=5460=1h => value=(time_in_seconds-60)+1920
From 1h to 1d with 1m resolution 5461=1h+1m, 1380+5460=6840=24h => value=(time_in_minutes-60)+5460
From 1d to 1500 days with 1h resolution 6841=25h, 6842=26h, and so on => value=(time_in_hours-24)+6840

The following tables show some Modbus commands examples.

Modbus protocol can be tested easily using a modbus program, like mbpoll for Linux:

mbpoll -v -m rtu -0 -1 -a1 -b115200 -Pnone -r 0 /dev/ttyUSB0 32 0 64 128 0 0 0 65280

to activate RL1 for 1s, R3 for 2s, RL4 for 4s and RL8 forever.

mbpoll -v -m rtu -0 -1 -a1 -b115200 -Pnone -r 255 -c 1 /dev/ttyUSB0

to read all port states.

Application notes

Heating/ventilation system

The following simple diagrams represents the connection to a heat pump (controlled by low voltage signals), a ventilation system (controlled by low voltage signals) and a 3-vias valve (supplied by 230Vac).

With Domoticz it's easy to get heating/cooling system with heat pump, optimized to consume most energy from photovoltaic, and a air renewable controlled mechanical ventilation with chiller and coil that regulates the relative humidity to get the maximum comfort.

For security reasons, do not mix high and low voltage loads in the same block! For example it's not safe to connect, on Block3, a 230V valve to RL8 and a 12/24V valve to RL7! On each relay block it is possible to use only low voltage or only high voltage loads.

ADSL router controlled by Domoticz script to prevent hang-up

The following schema shows how to use the normally-closed contact of SPDT relay to supply a router.
A script will check that internet is working, and in case of failure activate the reset to turn power supply OFF for 10 seconds, resetting the router.

Using DomBus31 with Modbus protocol with Node-RED

To be used with Node-RED, please assure that Modbus RTU version of DomBus31 has been chosen.

Install the modbus palette using the command npm install node-red-contrib-modbus 

Creasol DomBus31 is factory programmed to use default slave address = 49 (0x31, can be modified through register 8192), using serial parameters 115200, 8bit, no parity, 1 stop bit.

DomBus modules installation block chart

• Use a 12V power supply unit with backup battery charger, to avoid trouble on RaspberryPI or other devices. Also, in this way it's possible to get everything working even in case of power outage (domotic controller, domotic modules, network switches, routers, NVR and IPcams).
• Use a 12V lead-acid battery well dimensioned to supply everything during blackout.
• Use a DC/DC converter 12V → 5V 3A to supply the RaspberryPI, if you have it.
• To use DomBus modules, use a standard alarm shielded cable (within 4 wires) to interconnect all modules to RaspberryPI (through a cheap RS485 to USB adapter).
• Protect each bus with a fuse

Ports parameters

DCMD commands

This is an experimental function, undergoing testing and development, available on all DomBus modules, expept DomBus1

For each port it's possible to configure, through the Domoticz Description field, one or more DCMD commands.

DCMD is a command that is sent to the module itself or to another DomBus module, in response to an event, and more DCMD commands can be specified for the same event and port.

Also it's possible to send DCMD command to the domotica controller to activate, deactivate or toggle a scene/group; to get this feature please assure that:

• 127.0.0.1 was added to Domoticz → Setup → Settings → Trusted Networks field
• if Domoticz www port is different from 8080, manually replace 8080 with the used port in the plugins/CreasolDomBus/CreasolDomBusProtocol.py file:
  JSONURL = "http://127.0.0.1:8080/json.htm"

The syntax is DCMD(Event:ValueLow:ValueHigh)=ModuleAddress.ModulePort:Command:Value

where ValueLow, ValueHigh, Value are optional parameters.
When ModuleAddress corresponds to the same module that we're editing, the command is executed locally, by the same module.
When ModuleAddress corresponds to another Dombus module, the command is sent by bus to that module. When ModuleAddress is 0, the command is sent to the controller to activate the scene/group with idx=ModulePort : please note that ModulePort should be in hex format, so if ModulePort=11 the scene/group with idx=17 will be activated.

Example 1: configure a pushbutton switch to have 3 functions

IN_DIGITAL,INVERTED,
DCMD(Pulse)=0101.1:TOGGLE,
DCMD(Pulse1)=0101.2:ON:30m,
DCMD(Pulse2)=0101.2:OFF

Example 2: configure a pushbutton switch to trigger 2 scenes/groups

IN_DIGITAL,INVERTED,
DCMD(Pulse)=0.1:Toggle,
DCMD(Pulse2)=0.2:On

Example 3: temperature sensor that enable/disable electric heater and valve

In the description field of the temperature sensor we'll write

DCMD(Value:0:20.5)=0101.3:ON, (if temperature between 0 and 20.5°C, turns ON heater on output 3 of module 0x0101)
DCMD(Value:0:20.5)=0102.1:ON, (if temperature between 0 and 20.5°C, turns ON valve output 1 of module 0x0102)
DCMD(Value:20.8:50)=0101.3:OFF (turn OFF heater when temperature above 20.8°C)
DCMD(Value:20.8:50)=0102.1:OFF (turn OFF valve when temperature above 20.8°C)
Domoticz temperature sensor Description will be:

TEMPERATURE,
DCMD(Value:0:20.5)=0101.3:ON,
DCMD(Value:0:20.5)=0102.1:ON,
DCMD(Value:20.8:50)=0101.3:OFF,
DCMD(Value:20.8:50)=0102.1:OFF

Installation

Using RS485 specific cables it's possible to get almost 1km linear bus with several devices attached. Alternatively, it's possible to use 2 twisted pairs of cheap Cat6 UTP or STP cable, one twisted pair for data (A and B) and one for 12-24V power supply. Ideally, all devices should be connected using a linear bus topology, to get the lowest reflection/noise, and connect 100-150 Ohm resistor on the two ends, as illustrated in the Fig. 2. In practice, this is not important for common buildings.

At Raspberry/PC side, it's possible to use a cheap USB-RS485 adapter, if a serial port with RS485 driver is not already available.

Using DomBus modules it's possible to:

1. avoid RF pollution
2. no need to periodically change batteries on sensors/actuators
3. using a UPS or  13.6V power supply with backup battery, it's possible to get a building automation system that works also in case of power outage
4. very very low power consumption

Writing a microSD card with a fresh Raspbian + Domoticz distribution

Click here if you need to write a microSD card with a clean updated Raspbian+Domoticz image optimized to extend SD life (minimizing writings), and with some addons (firewall, backup, libraries).

Adding DomBus plugin to Domoticz

Linux version

This procedure is not needed in case of a new Domoticz installation writing the SD as written above.
If Domoticz does not already include the DomBus plugin, type the following commands (from Linux root shell: type sudo su - to become root):

#install git, if not already installed
which git
if [ $? -ne 0 ]; then sudo apt install git; fi

#change to the domoticz directory / plugins
cd /home/pi/domoticz/plugins 

#fetch the Python Plugin Manager (that can be used to install/upgrade other plugins, including Creasol DomBus)
git clone https://github.com/ycahome/pp-manager

#fetch Creasol Plugin
git clone https://github.com/CreasolTech/CreasolDomBus

#restart Domoticz daemon
service domoticz restart

Windows version

Domoticz configuration

After plugins installation and Domoticz restart, it's possible to add the Creasol DomBus hardware (Setup->Hardware , add new "dombus" hardware type "Creasol DomBus" and specify the serial device, normally /dev/ttyUSB0) and connect the DomBus device to the RS485 bus.
DomBus module is factory programmed with a default address indicated above, and only one port will be automatically added to the Switches panel of Domoticz. Enter the Switches panel, find the new device with the DomBus default address, click on Edit and add in the description ,HWADDR=0x0001 to set the new address to 0001, or specify another address of your choice. Reload the Switches panel to see all input/output/led ports of DomBusTH active.

With Domoticz, each DomBus port can be configured via the Domoticz device description: for example a port IN_DIGITAL normally is On when it's left unconnected, and Off when it's shorted to GND, but it's possible to invert this function specifying in the device description the parameter INVERTED, separated by a comma (,): IN_DIGITAL,INVERTED . Relay outputs can be configured writing in the description field OUT_DIGITAL or OUT_RELAY_LP: in the latter case, relay are internally managed to assure a low power consumption.
Please check the sections Ports capabilities and Ports parameters.

Ports that are not used can be disabled in Domoticz Setup → Devices clicking on the blue arrow of each useless port (device), but in case of a bus with almost 255 ports, it's suggested to disable the unused ports by using the DISABLE command:
1. suppose that DomBus module 0x0001 has ports 3,4,5,6,8 not used
2. in Domoticz Switches panel select port1 of that module ([0001.1] RL1)
3. click on Edit, and add in the Description field DISABLE=3:4:5:6:8 and click on Save.
In this way, the selected ports will be disabled and removed from the Devices list. With this solution it's possible to add more DomBus modules to the same bus, with up to 255 enabled ports. In large buildings, it's a good practice to have more than one bus, to divide floors or areas.

Updating DomBus plugin on Domoticz

1. Go to Setup → Hardware → PP-Manager (name of the python plugin manager)
2. Assure the PP-Manager is enabled
3. Pluging to install: select Creasol DomBus
4. Auto Update: choose Selected
5. Click on Update button

Linux platform, with DomBus plugin installed manually

cd DOMOTICZ_HOME/plugins (e.g. cd /home/pi/domoticz/plugins)
git clone https://github.com/CreasolTech/CreasolDomBus.git

Linux platform, with DomBus plugin installed using git

cd DOMOTICZ_HOME/plugins/creasolDomBus (e.g. cd /home/pi/domoticz/plugins/CreasolDomBus)
git pull

Windows platform

Files should be downloaded from the github repository https://github.com/CreasolTech/CreasolDomBus by using git program or www browser, then placed in the DOMOTICZ_HOME/plugin/CreasolDomBus directory

Installing CreasolDomBus Home Assistant custom component

cd /tmp
git clone https://github.com/CreasolTech/home-assistant-creasol-dombus.git
cp -a home-assistant-creasol-dombus/custom_components HADIR/config/
ha core restart

FAQ about DomBus products

• Some modules are available with both DomBus and Modbus protocol firmwares, so the best one for your needs should be chosen. Below in the FAQ some information about the two protocols
• You can connect up to 20-30 modules per bus: the max number of ports managed by Domoticz is 256, and you can use the DISABLE command to disable ports that are not used in case that 256 ports are not enough.
• It's good to make different buses on large buildings with several sensors and actuators, for example a bus for the ground floor, one for the second floor, ... Any bus is connected to a RS485 port/adaptor and need a DomBus plugin for that serial port, so in the Domoticz Setup→Hardware, one Creasol DomBus line for each serial port.
• DomBus modules are factory programmed with a certain address, for example 0xff12 for DomBus12, 0xff23 for DomBus23, and so on. As each device connected to the bus MUST have a unique address, add only one module to the bus then program its address using the command HWADDR=0x0001, then connect another DomBus module and program its address to 0x0002 and so on. Address can be chosen to identify floor and room, for example 0x1023 to identify floor 1, room 2, module 3 in that room.

How can I change address of DomBusTH device?

DomBusTH: how to mount and fix it?

DomBusTH: how to do a factory reset?

Why buzzer does not work?

2 or more modules with the same address

How many DomBus modules can I connect to a bus?

How to split a bus in 2 buses in Domoticz?

How to identify a RS485/USB adapter when more than one are connected

All DomBus devices have been duplicated!

I have many USB-serial adapters

Why there is a long delay between pushing a button and get light/output on?

Why DomBus device does not work?

One DomBus module stopped working

Why current consumption is 0uA?

How to add icons on smartphone to turn On/Off lights/loads, or enable/disable scenes/groups?

How to send Telegram notification from a lua script in Domoticz?

-- script_time_example.lua  : simple example script that write a message to Telegram channel/group if temperature is less than 5
commandArray={}
dofile "script/lua/globalvariables.lua" -- read a file with some variables, including Telegram API key and ChatID
dofile "script/lua/globalfunctions.lua" -- read a file with some functions
if (tonumber(otherdevices['Temp_outdoor']) < 5) then
	telegramNotify("Low temperature: bring flowers inside")	-- send message by Telegram
end
return commandArray

2022-11-04 Rev02g4

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2020-12-28

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