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PRELIMINARY - This product will be available in January 2021

Creasol DomBus31 is a din-rail module, 115x90x40mm, with 8 relays outputs. 6 relays are SPST (NO output) with 250V 5A max capability, and 2 relays are SPDT (NO and NC outputs) with 10A capability. It can be connected to the Domoticz controller by a RS485 serial bus (4 wires, 2 for 12/24V power supply, and 2 for data at 115200bps).

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 300mW! 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.

 

Creasol DomBus31 8 relays module for domoticz home automation system

Features

  • 6 relay outputs, SPST (normally open contact on screw terminal block) with 250V 5A contact
  • 2 relay outputs, SPDT (normally open and normally closed contacts on screw terminal block) with 250V 10A contacts
  • 7.5-35Vdc power supply (internally regulated by a switching mode power supply circuitry that minimize power consumption and dissipation)
  • low power consumption: 2.5mA stand-by current at 13.6V (35mW), 21mA with all relays ON at 13.6V (285mW)
  • 115200 bps RS485 bus (max length: 1km)

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. Be careful to connect all devices 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.

dombus connection

AN domoticz example2

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 this installation topology it's possible to avoid RF pollution and minimize connections, connecting DomBus devices in any room by a 4 wire shielded cable to exchange data and get power supply (normally battery-backed 12Vdc, to get the domotic system working even in case of blackout).

 

Configuration

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

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):

if [ ! `which wget` ]; then sudo apt install wget; fi
cd /home/pi/domoticz # or other directory where domoticz is installed
wget -O /tmp/CreasolDomBus.tgz https://codeload.github.com/CreasolTech/CreasolDomBus/tar.gz/master
if [ ! -d plugins/CreasolDomBus ]; then mkdir -p plugins/CreasolDomBus; fi
tar xvzf /tmp/CreasolDomBus.tgz -C plugins/CreasolDomBus --strip=1
service domoticz restart

Domoticz configuration

After plugin 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.
DomBusTH is factory programmed with default address 0xff51, and only one port will be automatically added to the Switches panel of Domoticz. Enter the Switches panel, find the new device “dombus - [Hff51] OUT1”, 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.

Each device port can be configured via the Domoticz switch description: for example a device type 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 switch description the parameter INVERTED, separated by a comma (,): IN_DIGITAL,INVERTED . Please check the following sections Port parameters and DomBusTH port capabilities.

I/O that are not used can be disabled in Domoticz Setup -> Devices clicking on the blue arrow of each useless device (I/O).

I/O parameters

Parameter name Function
HWADDR=0xNNNN This command set new address for the dombus device: reload the Switch panel to see the new devices associated with the new address of DomBus. NNNN is an exadecimal number, from 0x0001 to 0xff00, so 65280 combinations are available. Keep note of address assegnated to each dombus device, because in case of address conflict it's needed to switch off one of the conflicting device and program the remaining one to another address, or make a factory reset as explained below.
INVERTED Used to invert the logic state of an input or output. Can be used in conjuction with OUT_DIGITAL, OUT_RELAY_LP, IN_DIGITAL, DIMMER.
Normally, domoticz switch is On if input is at logic level high (open), and Off when it's shorted to ground. If INVERTED is specified, domoticz switch will be On when the corresponding input is shorted to ground, and vice versa.
OUT_DIGITAL Output, open collector, active low, On => output wire is shorted to GND (max current 50mA). Off => output is open (current=0).
OUT_RELAY_LP Not recommended: output, open collector, active low, but with duty cycle 25% to reduce power consumption on relays coil
OUT_DIMMER Set the output as DIMMER, from 0 to 100% using 5% step, 500Hz frequency. Suitable to control LED strip lights
OUT_BUZZER Set two outputs as BUZZER: a piezo buzzer can be connected to the selected two ports (configured in push-pull) to generate 5KHz frequency when the corrsponding Domoticz switch is On. The Domoticz switch can be configured as selector: in this case buzzer will output 1 or more short alerts to notify a status, similarly to the led configured as OUT_DIGITAL with Domoticz switch configured as Selector.
OUT_BLIND

Port configured to control a blind, in close direction. Next port will be automatically configured as blind in open direction.
Ports OUT1 and OUT2 can directly be connected to 12V relay coils (if Vbus is 12-14V, or 24V relay coils if Vbus is 24V).
Ports IN1..IN3 can be configured as OUT_BLIND, but in this case should be connected to relayboard that already have a transitors/optocouplers to drive relays.

OUT_LEDSTATUS Configure a LED port to show the device status (flashes when a frame is transmit to the RS485 bus)
IN_DIGITAL Digital input, is On when the corresponding input is at high voltage level (open), and Off when the corresponding input is at GND (shorted).
IN_ANALOG In DomBusTH there is one pad/hole where it's possible to solder a wire to measure an external DC voltage, <30Vdc; a solder jumper must be opened (because that pad is connected to Vbus).
Also, one or more of the 4 input wires can be configured as analog inputs, 0-3V range: a solder jumper in the PCB must be opened by cutter to disable the internal pullup resistor. Also, external resistive divider should be added to measure higher voltages, so the voltage at the input is less equal than 3V
IN_TWINBUTTON This is a method to connect two pushbuttons/switches to a single input, to get a UP/DOWN/STOP select switch. The two switches are connected together by a 4.7KOhm resistor, using the schema indicated in the application notes below.
A For analog and distance sensors: used to compute the real value using the formula  REAL_VALUE=A * VALUE_FROM_DOMBUS + B.
B For analog and distance sensors: used to compute the real value using the formula  REAL_VALUE=A * VALUE_FROM_DOMBUS + B

DomBus31 I/O/S capabilities

Port# Name Capabilities Default configuration Description
1 OUT1 OUT_DIGITAL, OUT_RELAY_LP, OUT_BLIND OUT_RELAY_LP SPST relay output, 5A 250V output capability, NO contact
2 OUT2 OUT_DIGITAL, OUT_RELAY_LP, OUT_BLIND OUT_RELAY_LP SPST relay output, 5A 250V output capability, NO contact
3 OUT3 OUT_DIGITAL, OUT_RELAY_LP, OUT_BLIND OUT_RELAY_LP SPST relay output, 5A 250V output capability, NO contact
4 OUT4 OUT_DIGITAL, OUT_RELAY_LP, OUT_BLIND OUT_RELAY_LP SPST relay output, 5A 250V output capability, NO contact
5 OUT5 OUT_DIGITAL, OUT_RELAY_LP, OUT_BLIND OUT_RELAY_LP SPST relay output, 5A 250V output capability, NO contact
6 OUT6 OUT_DIGITAL, OUT_RELAY_LP, OUT_BLIND OUT_RELAY_LP SPST relay output, 5A 250V output capability, NO contact
7 OUT7 OUT_DIGITAL, OUT_RELAY_LP, OUT_BLIND OUT_RELAY_LP SPDT relay output, 10A 250V output capability, NO and NC contacts
8 OUT8 OUT_DIGITAL, OUT_RELAY_LP, OUT_BLIND OUT_RELAY_LP SPDT relay output, 10A 250V output capability, NO and NC contacts

(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.

Application notes

Hardware ChangeLog

Firmware ChangeLog

Pin It
Creasol DomBus31 8 relays output module
SKU creDomBus31
Brand Creasol