DocumentationWB-MRPS6/S
6-channel power relay module
Covered order codes (1)
WB-MRPS6/S
Purpose
WB-MRPS6 six-channel relay modules switch general-purpose power loads, including inductive and capacitive loads: LED luminaires, incandescent lamps, switching power supplies, PDU applications and similar equipment.
The modules support a maximum current of 16 A (10 A nominal load) and can be used without intermediate contactors.
Not suitable for switching three-phase loads under the cited requirements, because the contacts must be mechanically interlocked for that application (GOST 30011.4.1, clause 7.2.1.1.5).
For relay selection, see Relay selection recommendations.
Technical specifications
| Parameter | Value |
|---|---|
| Power supply | |
| Supply voltage | 9–28 V DC |
| Power consumption |
|
| Outputs | |
| Number of outputs | 6 |
| Output type | Mechanical relay contacts |
| Contact configuration | Two-position, normally open (COM and NO) |
| Output arrangement | 6 outputs connected to relay contacts |
| Maximum switching voltage, AC | 250 V |
| Maximum switching voltage, DC | 30 V |
| Rated switching current per output at 230 V AC | 10 A |
| Maximum switching current per output at 230 V AC | 16 A |
| Maximum switching current per output, DC | 16 A at 24 V; 10 A at 30 V (resistive load, room temperature, service life of 20,000–50,000 switching operations) |
| Maximum inrush current (20 ms) at 230 V AC | 165 A |
| Contact resistance | < 100 mΩ |
| Contact material | W+AgSnO2 |
| Dielectric withstand voltage between relay coil and contacts | 5000 VAC (1 minute) |
| Dielectric withstand voltage between open relay contacts | 1250 VAC (1 minute) |
| Operating life | 12,000 operations at 16 A / 230 VAC |
| Detailed specifications | HF115F-S |
| Datasheet | HF115F-S.pdf |
| Inputs | |
| None | |
| Delays | |
| Startup Delay When Power On (s) | 0–999 s; default: 0 s |
| Restart Delay After Output Turn Off (s) | 0–999 s; default: 0 s |
| Indicators | |
| LED | See Indicators |
| Control | |
| Control interface | RS-485 |
| Interface isolation | Non-isolated |
| Communication protocol | Modbus RTU; software-configurable address; factory settings are printed on the label |
| RS-485 interface parameters | Software-configurable; defaults:
baud rate — 9600 bit/s; data — 8 bits; parity — none (N); stop bits — 2 |
| Ready after power-on | ~2 s |
| Operating conditions | |
| Ambient air temperature | −40 to +80 °C |
| Relative humidity | Up to 95%, non-condensing |
| Climatic classification under GOST 15150-69 | O2.1* |
| Warranty | 2 years |
| Service life | 8 years |
| Terminal blocks and wire cross-sections | |
| Recommended wire cross-section with insulated wire-end ferrules | control inputs: 0.35–1 mm2 — single ferrule; 0.35–0.5 mm2 — twin ferrule,
power inputs: up to 2.5 mm2 — single ferrule; up to 1.5 mm2 — twin ferrule |
| Standard ferrule sleeve length | 8 mm |
| Screw tightening torque | control inputs: 0.2 N·m,
power outputs: 0.5 N·m |
| Dimensions | |
| Width, DIN modules | 3 |
| Overall dimensions (L × W × H) | 53 × 90 × 58 mm |
| Weight (including box) | 195 g |
Operating principle
Indicators
The module has indicators that show its status without connecting to a controller:
- S (green) — Modbus communication status: lights up when low-voltage power is applied and flashes during polling over RS-485. On devices with events enabled in Fast Modbus ⚡ the indicator flashes more frequently than during sequential polling because events are polled faster. In bootloader mode it flashes once per second; during firmware upload it flashes rapidly.
- 1–6 (orange) — output state: lit when the relay contacts are closed.
Inputs
There are NO digital inputs.
Outputs
The module has six independent normally open relay outputs. The permissible current for DC loads is specified in the technical specifications. For permissible load power and type, see Relay selection recommendations.
Safety Mode
Safety Mode can stop a process if control over the module is lost, for example if the RS-485 cable is severed. Account for loss of controller communication when designing control systems (see Configuring Safety Mode)
Actuator Control
Despite the wide range of actuators with digital control, mains-switched actuators remain common for curtains, blinds, shutters, projector screens, air dampers, ball valves and similar devices. Their main control requirement is to prevent simultaneous activation of Open and Close.
The module's Actuator Control combines two relays into one control and uses a software interlock to prevent both relays being energised simultaneously. It also inserts a 500 ms delay when reversing direction and energises the relays for the configured duration (10 seconds by default).
For actuator safety, relay coil commands are ignored in this mode. These outputs can be controlled only through Actuator Control registers.
Actuator Control is disabled by default. Enable it in the settings before use; delays are configured there too.
Delays
Startup Delay When Power On (s) starts when the device firmware boots, approximately 2.5 s after low-voltage power is applied. It switches outputs on sequentially to protect supply circuits from combined inrush currents.
Restart Delay After Output Turn Off (s) starts when the relay switches off. It protects loads sensitive to frequent switching, such as compressors and pumps.
Delays are configured separately for each relay output.
Output timer functions
Timer functions switch module outputs on or off according to a defined timing sequence.
Direct control and timer functions can be used in the same module. Each output can have only one timer function. Outputs are configured independently; changing one output does not affect the others. More about relay module timer functions.
Each relay output supports these timer functions: On Delay, Off Delay, Switch on for a time, Switch on for a time (with command reset), Switch off for a time, Switch off for a time (with command reset), On/Off Cycle.
Installation
Mount the device on a standard 35 mm DIN rail. The V+ GND A B terminal block, with a 3.5 mm pitch, connects the power supply and RS-485 communication bus. Correct bus wiring is essential for reliable communication; see RS-485 bus wiring and connection.
If devices on the RS-485 bus use different power supplies, their GND terminals must be interconnected. See Grounding Wiren Board devices and connecting GND and iGND.
Use flexible stranded wire with insulated wire-end ferrules (NSHVI).
Strip the insulation to the sleeve length, or strip a little more and trim the protruding wire after crimping. Use a ferrule crimping tool. A crimped ferrule protects the strands from the screw clamp and secures the connection.
Do not overtighten the terminal screws: excessive force damages the screw terminal.
Relay switching briefly increases power consumption (see specifications). Choose a supply with adequate power reserve. For long supply cables, allow for the voltage drop along the cable.
The conductor cross-section at the relay output screw terminals must suit the switched load. The screw terminals accept 2.5–4 mm2. Install the relay module to meet electrical safety requirements and prevent accidental contact with live high-voltage terminals. Operate the device under the recommended environmental conditions.
Installation example
One way to connect loads to WB-MRPS6 is shown in the diagram WB-MRPS6 installation example.
In this example, wiring before and after the relay is protected by a 10 A circuit breaker. Select its rating for the installed conductor size and the module's maximum switching current.
The diagram connects a water heater, a fan, an LED lamp and an incandescent lamp to K1–K4. Outputs are controlled over RS-485.
Connecting curtain actuators
Before connecting a curtain actuator, enable Actuator Control for the outputs used! Incorrect configuration can energise both relays simultaneously and may damage some actuators.
A curtain actuator uses two relays, typically connected to mains phase L and the actuator's Open and Close wires. The actuator is also connected to neutral N and protective earth PE. Always check the proposed wiring against the actuator documentation.
Up to three curtain actuators can be connected to one WB-MRPS6.
| Actuator | Outputs |
|---|---|
| 1 | K1 - open, K2 - close |
| 2 | K3 - open, K4 - close |
| 3 | K5 - open, K6 - close |
Configuration
Configuration methods
- Set the parameters in the Wiren Board controller web interface under Settings → Configs → Serial devices driver configuration. If these items are unavailable, check your access level.
- Write settings to the Modbus registers of the module from the controller console using the utility modbus-utils-rpc or modbus_client.
- Without a Wiren Board controller, use the Wiren Board device web configurator or other software; see Using Wiren Board Modbus devices without a controller. You will need a computer with an interface converter: USB-RS485.
Our devices are continually improved. If settings described in this manual are missing, update the device firmware and controller software.
Output states at power-on
The following power-on behaviours are available:
- Safe state (default) — after power-on, outputs follow the setting Output Safe State;
- Restore last state — saves the last output state and restores it when power returns.
Safety Mode
Safety Mode can stop a process if control of the module is lost, for example because the RS-485 cable is severed. Account for communication loss when designing control systems.
The fail-safe timer restarts after every successfully received and processed Modbus packet. The module enters safe mode when the configured time expires. Normal operation resumes when communication returns. The default timeout is 10 seconds.
Each output has a configurable fail-safe state and can be configured to enter it on communication loss.
Input control behaviour can be configured:
- Don't change — previously enabled input control remains enabled.
- Block in safe mode — inputs cannot control the relays.
- Allow only in safe mode — input control blocked in normal operation becomes available in safe mode.
Actuator Control
To use an actuator, select the corresponding output mode on the Actuator Control tab. Opening/closing times, direction-change pause, power-on actions and safe-mode actions then become available.
Outputs in one module can use different modes: for example, K1 and K2 can control an actuator while K3–K6 operate normally.
Configuring protective delays
In the device settings, open Protective Functions and set the Startup Delay When Power On (s) or Restart Delay After Output Turn Off (s) for the corresponding relay output.
Configuring output timers
In the device settings, open Timers, select a function and configure its duration for the corresponding relay output.
- Protective delay and timer configuration examples
-
Configuring protective delays in the Wiren Board controller web interface -
Configuring relay timers in the Wiren Board controller web interface
Wiren Board controller web interface
Selecting a template
To display the device on the Devices tab of the Wiren Board controller web interface, add it automatically by scanning for Wiren Board devices on RS-485 or manually by selecting the template WB-MR6CU v.2, WB-MRPS6.
Controlling the device and viewing values
The web interface allows you to control device outputs and view readings. To change the displayed channels, edit the device configuration in the wb-mqtt-serial driver settings.
- Wiren Board controller web interface
-
WB-MRPS6 controls and indicators -
Actuator Controls in Actuator Control
Modbus operation
Wiren Board devices use Modbus RTU. The physical connection uses the RS-485.
interface. All main commands for reading and writing one or multiple registers are supported. See the list in the Modbus protocol description.
The module can be configured:
- in the Wiren Board controller web interface;
- using the Wiren Board device web configurator;
- using third-party software.
Default port settings
| Value default |
Parameter name in the web interface |
Parameter |
|---|---|---|
| 9600 | Baud rate | Baud rate, bit/s |
| 8 | Data bits | Number of data bits |
| None | Parity | Parity |
| 2 | Stop bits | Number of stop bits |
In current firmware, setting Stop bits is optional: the device also operates correctly when its number of stop bits differs from the Modbus master setting.
For a faster response, we recommend increasing the baud rate to 115200 bit/s; see Communication parameter settings
Modbus address
Each device on the bus must have a unique address from 1 to 247. The factory-assigned address is printed on labels on the enclosure (top cover, side or underside). Devices in a production batch are assigned different addresses, so devices in one order will usually have different addresses.
For instructions on finding, changing or resetting the address, see Wiren Board device Modbus address.
Fast Modbus extension
Fast Modbus extends standard Modbus with rapid discovery of Wiren Board devices on RS-485 and event polling.
These features are enabled by a special command from the master, so Wiren Board devices remain compatible with third-party equipment.
Not every register supports event generation. Check the register map: event-capable registers are marked with ⚡. See Fast Modbus.
Register map
Firmware updates and resetting settings
Wiren Board devices support firmware updates over Modbus. This allows bugs to be fixed at the installation site and, where technically possible, new features to be added. Settings stored in the device are retained during a firmware update.
Instructions:
- Firmware update ()
- Resetting settings
- Connection parameter settings
- Modbus address: find, reset or change
- Updating the bootloader
New firmware releases are listed in the firmware changelog.
Known issues
Hardware revisions
Troubleshooting
Interference from relays and contactors
Relays and contactors can interfere with nearby devices. When switching loads, especially inductive loads, the contacts generate high-frequency transients with amplitudes of several kilovolts, which may couple into other circuits. Snubber networks suppress these transients, reducing interference and improving equipment stability. See Interference when switching inductive loads
Device images and drawings
CorelDRAW 2018 (font: Ubuntu): File: WB-Library.cdr.zip
Visio:
- Wiren Board devices: File: WB-Visio-Lib.zip.
- Enclosures, circuit breakers, contactors and other third-party symbols.
Autocad 2013 DXF: File: WB-MRPS6.dxf.zip
Autocad PDF: File: WB-MRPS6.pdf
AutoCAD Electrical schematic symbol library: File: Wirenboard-AE-base.zip