Product Features

◆ DC7-30V wide voltage power supply

RS485 communication isolation

The communication interface supports RS232 RS485。

◆ Supports standard Modbus protocol and ASCII/RTU format

The measurement chip adopts a 24 bit AD converter, with an accuracy of 0.02 degrees

PRODUCT FUNCTION

◆8 PT100 acquisition channels

◆Supports 5-digit addressing addresses;

◆Supported baud rate: 2400480096001920038400

Product Selection

Main parameters:

Mechanical dimensions and installation

Adopting a guide rail installation method
Interface Description:

wire connectionway

PT100 adopts a three wire wiring method

RS485 wiring diagram

Address Description

The device address consists of two parts: the dip switch address and the device base address.

Dial switch address: It is a five digit dial switch address. (Range 0~31)

Device base address: refers to the address set by software, also known as offset address.

The specific relationship is:Device address=dip switch address+device base address (without dip switch device: device address=device base address).

1. When all five dialing codes are dialed to the "ON" position, it is the address "31";

2. When all five dialing codes are dialed to the "OFF" position, it is the address "0";

3. The leftmost 1 is the binary lowest bit;
4. Address table.

Register Description

This control card mainly serves as a temperature register and supports the following instruction codes: 3, 4, 6

Temperature register address table:

Example of Communication Instructions

This product supports standard Modbus instructions. For detailed instruction generation and parsing methods, please refer to the register table in this article and consult the "MODBUS Protocol Chinese Version". reference resources: http://pan.baidu.com/s/1hqsuZNu

Application example and explanation: In addition to the dip switch address, the default broadcast address for this device is 254. When there is only one device on the bus, there is no need to worry about the dip switch address. Simply use the 254 address. When there are multiple devices on the bus, select different addresses through the dip switch and send control instructions based on address differentiation.

Note: The RS232 bus is a 1-on-1 bus, which means there can only be two devices on the bus, such as a computer and a relay board. Only the 485 bus can mount multiple devices.

Instruction generation instructions: For instructions not listed in the table below, users can generate them themselves according to the Modbus protocol. For reading and writing relay coils, it is actually reading and writing coil registers in the Modbus register. The address of the relay register has been explained in the previous text, and users only need to generate read and write instructions for register operations. For example, reading or writing the status of relay 1 is actually a read/write operation on the coil register 0001 corresponding to relay 1.

Detailed explanation:

1: Analog quantity query

Query the temperature of the first channel

FE040000000125C5

Simulated return information:

FE 04 02 00 00 AD 24

Test software description

Test software download

Software functions:

Monitoring temperature

Temperature line loss compensation

Modify baud rate and device address

Methods for changing baud rate and device address

Open the collection configuration software, select the serial port settings menu, click on "Close Serial Port" in the communication parameters, select the corresponding serial port number and baud rate (default 9600), and change the timeout and minimum interval to 50ms. Select PT08 as the device model in the basic parameters. Click to open the serial port, click the read button, and if the information bar below shows' read successful ', it means the connection is successful. (If it shows' communication failure', please make sure the serial port wiring, serial port number, baud rate, and address are correct.).

After confirming successful communication, select the correct baud rate and device address to be configured in the basic parameters, click write. If the information column below shows successful write, it means the operation is successful. You can click read to confirm the operation result.

The device address consists of two parts: the dip switch address and the device base address.

Dial switch address: It is a five digit dial switch address. (Range 0~31)

Device base address: refers to the address set by software, also known as offset address.

The specific relationship is:Device address=dip switch address+device base address (without dip switch device: device address=device base address).

If the device address is less than 31, use the dip switch. If it is greater than 31, the device base address needs to be modified.

For example, if the device address is set to 100 and the dip switch address is set to 0, the device base address should be written as 100.

PT100 line resistance correction

The sensor temperature can be compensated under the line loss compensation menu. Corresponding relationship between line loss value and temperature: 380 milliohms=1 ℃

For example, the actual temperature is 20 degrees now, and the first display shows a temperature of 20.1 degrees. It is said that the temperature is 0.1 degrees higher, corresponding to a PT100 resistance of 38 milliohms. Fill in 3.8 in the online loss value input box, and click on the one after the first displayAfter successful writing, the write result will be displayed in front, completing the first correction;

On the contrary, the actual temperature is 20.1 degrees, and the first display shows a temperature of 20 degrees. It is said that the temperature is 0.1 degrees lower, corresponding to a PT100 resistance of 38 milliohms. Fill in -3.8 in the online loss value input box, and click on the one after the first displayAfter successful writing, the write result will be displayed in front, completing the first correction. Similarly, other channels can be corrected.

Under the monitoring menu, the temperature and change curve of each channel can be monitored in real time.

To control multiple devices, you can use the one provided by our company“Juying configuration software”For details, please refer to the instructions of the Juying configuration software. pdf

Download link for Juying configuration software: http://pan.baidu.com/s/1pXvdG

Common problems and solutions

1. After the relay board is powered on, communication cannot be established using the 232 interface and cannot be controlled

Firstly, test whether different baud rates can be controlled. Pay attention to the A+, B-line, and shielded line of the 485 interface. Shielded line is not necessary, but it must be connected in cases of high communication error rate, even if the distance is very close.

On the 2.485 bus, with more than one device mounted, I sent the relay 1 draw sum with broadcast address 255, but not all modules have relay 1 draw sums.

When there is only one device on the bus, the broadcast address can be used. If there are more than one device, please use a dip switch to distinguish the address for control. Otherwise, the module may not execute instructions correctly due to asynchronous judgment of communication data.