Modbus protokoll rs485

Modbus Rtu 2

Hardware Resources:

 *   RS485 communication interface
 *   TTL communication interface
 *   2 optocoupler isolation input
 *   2 way optocoupler isolation output
 *   A user button
 *   A user LED
 *   A power indicator
 *   A STM32F030F4 microcontroller
 *   2 relay status indicators LED lights
 *   Power supply terminal interface (12V power supply)

Modbus RTU Instructions:

Baud rate: 9600 8 NONE 1

Hexadecimal send
hexadecimal receive

Operation steps:
1. Software settings communication baud rate
2. Set the address (communication using the device address, the default address is 01)

Set the address from 01 to 09 or from Broadcast to 09

Hex Byte	Funktion
01 10 00 00 00 01 02 00 09 66 56	Current address 01 is changed to 09
00 10 00 00 00 01 02 00 09 6B C6	Broadcast Address Modified to 09

Read Address

Hex Byte	Funktion
00 03 00 00 00 01 85 db	Send to Device
00 03 02 00 01 44 44	Receive from Device 01 for Address

Meaning of each byte:

Byte 1: address
byte 2: function
byte 3 4: register address
byte 5 6: register data
byte 7 8: CRC check

[address 1]

Hex Byte	Funktion
01 05 00 00 FF 00 8C 3A	0 relay ON
01 05 00 00 00 00 CD CA	0 relay off
01 05 00 01 FF 00 DD FA	No. 1 relay ON
01 05 00 01 00 00 9C 0A	No. 1 relay off
01 05 00 02 FF 00 2D FA	No. 2 relay ON
01 05 00 02 00 00 6C 0A	No. 2 relay off
01 0F 00 00 00 08 01 00 FE 95	Full off
01 0F 00 00 00 08 01 FF BE D5	all bright
01 01 00 00 00 08 3D CC	Send : Read all relay states
01 01 01 00 51 88	Return : Relay fully closed
01 01 01 03 11 89	Return : All relays are on
01 02 00 00 00 08 79 CC	Send : Read all input switch status
01 02 01 00 A1 88	Return : 8 input states

https://hacktronics.co.in/2-channel-relay-module/modbus-rtu-2-way-relay-output-2-way-input-switch-ttl-rs485-interface-communication

Modbus Rtu 4

Specifications:

 *   RS485 communication interface
 *   TTL communication interface
 *   4 optocoupler isolation input
 *   4 way optocoupler isolation output
 *   A user button
 *   A user LED
 *   A power indicator
 *   A STM32F030F4 microcontroller
 *   4 relay status indicators LED lights
 *   Power supply terminal interface (12V power supply)

Modbus RTU command

Baud Rate: 9600 8 NONE 1

Hex Byte	Funktion
00 06 40 00 00 01 5c 1b	Setting address is: 01
00 06 40 00 00 02 1c 1a	Setting address is: 02
00 03 40 00 00 01 90 1b	Read address
	Read the software version
00 03 00 04 00 01 c4 1a	[month] broadcast read (only by one device to address all practical, easy to test)
	Read the hardware version (PCB version)
00 03 00 04 00 01 c4 1a	broadcast read (only by one device to address all practical, easy to test)

[address 1]

Hex Byte	Funktion
01 05 00 01 01 00 9d 9a	No. 1 relay ON
01 05 00 01 00 00 9c 0a	No. 1 relay off
01 05 00 02 01 00 6d 9a	No. 2 relay ON
01 05 00 02 00 00 6c 0a	No. 2 relay off
01 05 00 03 01 00 3c 5a	No. 3 relay ON
01 05 00 03 00 00 3d ca	No. 3 relay off
01 05 00 04 01 00 8d 9b	No. 4 relay ON
01 05 00 04 00 00 8c 0b	No. 4 relay off
01 05 00 ff 00 00 fd fa	Quanmie
01 05 00 ff ff ff fc 4a	All light

https://hacktronics.co.in/4-channel-relay-module/4-channel-relay-module-programmable-w-opto-isolated-rs485-stm8s103f3