Acquire sensor temperature over serial communication

1. Objective

Use Serial Communication to acquire temperature from a temperature/humidity sensor, process it, and display results in real time.

2. Devices and plugins

• Devices

(1) RSDS13 RS485 temperature/humidity sensor, the acquisition data source.

Consult its manual or manufacturer website for protocol, communication output, and baud rate:

key	name
Interface	ttyO3
Baud rate	19200
Data bits	8
Parity	None
Stop bits	1
Temperature read command	0f 03 00 00 00 01 85 24

(2) EPC-R3220 device.

Under Interface configuration, set both COM1 and COM2 serial modes to RS485.

• Plugins

Serial Communication, Data Processing, and MQTT Upload.

3. Rules

(1) Connect the RSDS13 RS485 sensor and EPC-R3220 according to the applicable wiring requirements.

(2) Enter the relevant parameters to acquire sensor data.

The resulting connection scheme is:

4. Key steps

(1) Configure Serial Communication acquisition.

1). Connection settings. Scheme name is required.

Set sensor parameters as illustrated and enter:

• Scheme name: Serial scheme 1
• Interface: ttyO3
• Baud rate: 19200
• Data bits: 8
• Parity: None
• Stop bits: 1

2). Data frame configuration. Frames are parsed only when their enabled state is enabled.

Select Add configuration, enter data, and confirm. Valid data adds a new entry.

The device address (id) is 1. Enter:

• Name: Group 1
• Frame mode: HEX
• Frame format: 01 03 00 00 00 01 84 0A
• Cycle time: 2000
• Enabled: Enabled

Note:

The RS485 temperature read command sends 01 03 00 00 00 01 84 0A.

Command	01	03	00	00	00	01	84	0A
Meaning	Device address	Read command	Register start address high byte	Register start address low byte	Read quantity high byte	Read quantity low byte	CRCL	CRCH

84 0A is the 16-bit CRC result for 01 03 00 00 00 01.

The CRC rule is CRC-16/MODBUS X16+X15+X2+1.

3). Data frame parsing.

Select the tabs at the top → Add configuration, enter data, and confirm. Valid data adds a new entry.

Enter:

• Name: Parser 1
• Parsing: byte[3]byte[4]
• Enabled: Enabled

5. Results

Open Digital Twin, hover over Serial Communication, select the scheme, and view real-time data.