AC Dimmer Modbus RTU RS485 / key (100...240V, DIN Rail)


The module can be operated remotely with RS485 line (up to more than 1 km long) via standard Modbus RTU commands as well as it can work as a standalone dimmer operated with a key (input).

Modbus functions: can be called with any Modbus RTU compatible PLC/software using standard reading/writing from/to Modbus registers (examples available in the manual):

Modbus register address





Load powering level  (R/W)

0 (power off) to 255 (full power)



Smoothness (R/W)

0 to 255 sec



State after power on (R/W)

0x00 - off state; 0xFF – on state



AC frequency (R/W)

0x32 – 50 Hz; 0x3C – 60 Hz


“Load powering level” contains a value in range from 0 to 255, which sets part of sine wave allowed to come from source to the load. That means, for example:

-          the load will receive full AC wave when register 0x01 contains 0xFF (255) value;

-          the load will receive 1/5 of each AC wave when register 0x01 contains 0x33 (51) value;

-          the load will receive half of each AC wave when register 0x01 contains 0x80 (128) value;

-          the load will receive no AC power when register 0x01 contains 0x00 (0) value.

Smoothness parameter (register 0x02) can be changed in order to provide smooth turning on/of while using input (button).

When the module is powered on it can turn the load on according to set brightness level or it can start with load powered off completely. That setting can be chosen by writing to register 0x03.

The module work’s based on known network frequency so that parameter has to be set according to local network. One of two main standard network frequency (50Hz / 60Hz) values can be chosen by writing to the register 0x05.

Size: standard DIN rail 51 mm wide enclosure (51x116(including connectors)x68 mm).

Load: The maximal allowed short-time current is 12A, the maximal permanent load depends on the load parameters, used powering levels and is limited by heating. The device contains aluminium radiator, though placed inside the plastic box so we strongly recommend not to connect maximal load in order to avoid overheating. 

Power supply/power consumption: voltage - 12V, current - 50mA (module consumption).

Memory: non-volatile memory chip for settings.

Connection: screw connectors.

Modbus address: (can be changed by Modbus command) 0...255 (default address: 0x01).

Baudrate: (can be changed by Modbus command) 2400, 4800, 9600, 19200, 28800, 38400, 56000, 57600, 115200, 128000, 256000 (default is 9600).

Port settings: 8n1

Manual and testing software: the links to download will be sent along with the module.


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