QT350 wireless temperature measurement terminal-Global supplier

13th Floor, Building I1, Zhongjian Optics Valley Star, No. 799 Gaoxin Avenue, Donghu High tech Zone, Wuhan City

QT350 wireless temperature measurement

I. Overview

The QT-350 series intelligent wireless temperature measurement device is a device developed by our company to detect the temperature rise of electrical contact points in a timely manner, which is caused by factors such as material aging, poor contact, and current overload. This product adopts low-power design, wireless temperature measurement technology, and other features such as thorough isolation, easy installation, strong anti-interference ability, and reliable operation, which can effectively solve the problem of temperature measurement under high voltage conditions.

Application: Temperature monitoring of high-voltage switchgear contacts and contacts, knife switch, high-voltage cable intermediate heads, dry-type transformers, low-voltage high current cabinets, cables and other equipment.

2、 Device composition

This product consists of a central processing unit (1 unit) and wireless temperature transmission sensors (3-45 units).

1) Wireless sensor battery level

Special note: (Change the temperature group address field to FEFEH)

In order to prevent arbitrary changes, it is not displayed in the menu and can only be modified through communication, and can only be modified through separate instructions. The instructions are as follows: XX is the number of groups, 1 group has 3 points, and the maximum is 15 groups (45 points)

ADD10FEFE0001XXCRC

Address write function code, modify route length, group number, CRC

Example: Change the temperature to 6 o'clock (2 groups), device address to 01, and the instructions are as follows:

0110FEFEFEFEFEFE0001000B

0110FEFEFEFEFEFE0001000C

0110FEFEFEFEFEFE0001000D

0110FEFEFEFEFEFE0001000E

0110FEFEFEFE0001000A0110FEFE0001000F

2) Data recording

3、 Technical parameters

4、 Installation of sensors

As shown in Figure 1, the temperature sensor is installed at the location where temperature monitoring is required (such as the static contact, main busbar, etc.). A. Install a temperature sensor for each phase of phases B and C. The busbar is fixed with a dedicated heat shrink tubing, and the measured temperature simulation value is sent to the wireless transmission box using a data cable. The wireless transmission box is installed on the bus that is at the same potential as the temperature sensor, and does not require special insulation treatment.

5、 Operating instructions

1. Key Function Description

The functions of the 5 buttons from left to right are defined as follows:

Button 1: Mute button

Button 2: Flip Up

Button 3: Scroll down/cursor left key

Button 4: Menu/Return button

Button 5: Confirm/Combination Key

2. Operating instructions

After normal startup, enter the loop display and switch to a page every 4 seconds. When displaying in a loop, press the up or down button to enter the manual switching display interface.

Press the menu key to enter the password input interface. The default initial password is 8888. In the input interface, use the left arrow key to move the cursor and the up arrow key to add values.

After the password is correct, press the confirm button to enter the main menu.

The main course menu is as follows:

4) Wireless sensor temperature

5) Environmental temperature and humidity

6) Time and Date

2) Switching quantity

3) Wireless sensor address

6、 Settings:

1. Communication settings:

Address: 1-247

Baud rates: 2400, 4800, 9600

Parity: None, Even, Odd

2. Parameter settings:

Date: perpetual calendar date

Time: perpetual calendar time

Warning value: Contact temperature measurement over temperature warning value

Alarm value: Contact temperature measurement over temperature alarm value

Heating value: starting value for low-temperature heating with temperature measurement inside the cabinet

Cooling value: starting value of high-temperature fan for temperature measurement inside the cabinet

Dehumidification value: starting value for dehumidification of humidity inside the cabinet

Password: Change login password

3. Wireless settings:

Group address: Wireless temperature measurement group address (all temperature measurement points on the same device need to be in the same group)

Sub address 01: Sub station number 1

Sub address 02: Sub station number 2

Sub address N: Sub station number N

4. Event record:

View records: up to 999 records, enter one data X between 1-999, view the Xth record

The record display format is as follows: Below is the time when the record was generated, and in the middle are the temperature and the point where the alarm was generated. A02 indicates that the A channel of Group T2 has exceeded the temperature limit, with a temperature value of 46.3 ° C

Record reset: Clear all records

2) Combination function keys

Simultaneously press and hold the confirm button and scroll down button to enter the battery monitoring display interface. Description: The battery level is displayed as 0% -99% (optional function)

Simultaneously press and hold the confirm button and the scroll up button to enter the switch display interface. Explanation: The closed state displays the number 1, while the open state displays the number 0

3) Mute button

When the wireless temperature exceeds the warning value, the buzzer will give a warning prompt. At this time, pressing the mute button can mute it. After pressing the mute button, the buzzer will not give a warning prompt again until a new warning is generated. If a new warning is generated, the buzzer will continue to give a warning prompt

7、 Central Processing Unit Panel Hole Size Diagram and Terminal Definition Diagram:

7.1 Dimensions: 174mm (height) X124mm (width) X60 (depth)

7.2 Hole size: 163mm (height) X105mm (width)

Upward frame format from station data

8.3 Common protocols

Note: The maximum number of registers set and read at a time is 30. If the maximum value is exceeded, it will cause overflow errors!

1) Common variables and parameters

Upward frame format from station data

2) Continuous write multi register instruction (10H)

Main station data downlink frame format

7.3 Wiring Terminal Description Table

8、 Communication Usage Instructions

The RS485 communication interface of the device supports MODBUS-RTU communication protocol. The baud rate can be set between 2400, 4800, and 9600. Shielded twisted pair cables are required for communication interface connection, and the communication distance should be controlled within a range of 1KM.

8.1 Overview of the Agreement

1) Protocol type

The device adopts MODBUS-RTU protocol and is suitable for real-time communication of embedded instruments. The purpose of this agreement is to stipulate that data exchange between terminal devices (slave stations) and bus interface units (master stations) shall be implemented in RTU mode of MODBUS. The protocol adopts asynchronous master-slave half duplex communication mode, where communication is initiated by the master station and the slave station only receives responses without the ability to initiate communication actively. Communication response time<0.1S.

2) Physical layer

Transmission interface: RS485

Mailing address: 0-247

通信速率： 2400－9600bps

Communication medium: shielded twisted pair cable

3) Data link layer

Transmission method: Asynchronous master-slave half duplex mode

Data frame format: 1 start bit, 8 data bits, no checksum, 1 stop bit

data packet format

Address Domain:

The address field is located in the first byte of the data packet and consists of an 8-bit data, used to identify the address information of the slave station. This address must be unique on the bus, otherwise it will cause communication chaos. The valid range of the slave station address is [0247], where address 0 is the broadcast address.

Function Domain:

The functional domain sent by the host describes what functions the slave performs, and the following table defines the function codes

Data Domain:

The data area varies according to different function codes. The data area can be actual numerical values, set points, and addresses sent from the host to the slave or from the slave to the host. The data area contains what actions need to be performed by the slave or feedback information collected by the slave, which can be numerical values, reference addresses, and so on. For example, if the function code tells the slave to read the value of a register, the data area must contain the starting address and read length of the register to be read. If the function code tells the slave to set the values of certain consecutive registers, the data area should also contain these values. For different slaves, the address and data information may not be the same.

Check code (CRC):

The checksum can be used by the host or slave to determine whether the received information is incorrect. Sometimes, due to electronic noise or other interference, information may undergo subtle changes during transmission. At this time, the verification code calculated by oneself based on the information may not match the verification code contained in the information, resulting in an error in judging the received information. The checksum ensures that the host or slave does not respond to erroneous information during transmission, increasing the security and efficiency of the system. The verification code adopts CRC-16 verification method.

The steps for calculating CRC code are:

(1). Preset a 16 bit register as FFFFH. Call this register the CRC register;

(2). Separate the first 8-bit data from the lower bit of the CRC register and place the result in the CRC register;

(3). Move the contents of the register to the right by one bit (towards the lower bit), fill the highest bit with 0, and check the lowest bit;

(4). If the lowest bit is 0: Repeat step 3 (shift again). If the lowest bit is 1: XOR the CRC register with polynomial A001 (1010000000000001);

(5). Repeat steps 3 and 4 until the entire 8-bit data is processed by shifting it to the right 8 times;

(6). Repeat steps 2 to 5 to process the next 8-bit data;

(7). The final CRC register obtained is the CRC code. (CRC code=CRC-L+CRC-H)

8.2. Detailed explanation of application layer functions

1) Read Data Instruction (03H)

Main station data downlink frame format