RS485 4 kanalų 12V DC relių Modbus RTU modulis su STM8S103

The "Relay Module STM8S103" is a RS485 MODBUS RTU I/O module based on the STM8S103F3P6 (sometimes STM8S003F3P6). It offers 4 relays (NO, NC), 4 input terminals, and an RS485 interface. The input terminals are connected to unprotected 3.3V GPIOs, two of which can be used as analog inputs, timer inputs or, e.g., PWM outputs. Perfect board for small control applications.

Note1: The stock firmware MODBUS server implementation doesn't meet basic timing requirements and some MODBUS clients might not work (see analysis here). A Forth based MODBUS server implementation that allows for many new applications is WIP (discussion and code see Issue #238).

Note2: there are two known board variants: V1.00, and V1.06. This page describes V1.06 boards. V1.00 boards variant don't provide pads for a UART header, which is a clear disadvantage, and it's unknown if other differences exist.

The relay board has the following characteristics:

• STM8S103F3P6, SWIM interface on 4 pin header (pins unpopulated)
• 3.3V internal supply voltage (not "5V" as often advertised!)
• 8MHz crystal (the HSI can be used for 16MHz operation)
• unprotected inputs, two of them with an analog input option
• RS485 interface (e.g. for MODBUS)
• RX/TX with 3.3V level on unpopulated 4 pin header pads (variant V1.06)

Specifications:
LED light: Yes
Power supply voltage: 12V
Channels: 4
Baud rate: 9600
Microcontroller: STM8S103F3
Communication interface: RS485
Reset button: Yes
Size: Approx. 7.8 x 7.7 x 1.8cm / 3 x 3 x 0.7inch
Quantity: 1pc
Weight: 85g

Testuota per RS485 Modbus. Slave ID = 1, 9600 8-N-1.

Palaiko šias Modbus funkcijas:

05: write single coil;

01: read coils;

03, 06 : read single register ir write single register (nustatymams);

Serial operation instructions:

Below are the test instructions for device number 1:
No. 1 relay on:
01 06 00 01 01 00 d9 9a

No. 1 relay off:
01 06 00 01 01 01 18 5a

No. 2 relay on:
01 06 00 01 02 00 d9 6a

No. 2 relay off:
01 06 00 01 02 01 18 aa

No. 3 relay on:
01 06 00 01 03 00 d8 fa

No. 3 relay off:
01 06 00 01 03 01 19 3a

No. 4 relay on:
01 06 00 01 04 00 da ca

No. 4 relay off:
01 06 00 01 04 01 1b 0a

All off:
01 06 00 01 00 00 d8 0a

All on:
01 06 00 01 ff ff d9 ba