LCD dual-display communication temperature and humidity controller PT500-GSP885

1、 Product Overview
PT500-GSP885 digital temperature and humidity controller is a high-performance industrial temperature and humidity transmitter with battery recording function. It measures the temperature and humidity of the environment and displays it on the local display screen in digital form. When the measured data exceeds the limit, output the control signal and generate an audible alarm signal; At the same time, in response to the command sent by the host, the measured data will be uploaded to the host in the form of data packets through the RS485 bus, and the data will be recorded according to the set recording cycle.
The temperature and humidity transmitter has the characteristics of small size, light weight, wide range, high accuracy, fast response speed and good long-term stability, which makes it widely used in building automation, climate and HVAC signal acquisition, climate stations in museums and hotels, warehousing and logistics, medical industry, computer room temperature monitoring and other important measures and control of temperature and humidity in the air

The field of the system.
Function Introduction
·High precision and high stability temperature and humidity sensor
·Large display screen with backlight
·Small size, light weight, low power consumption, fast response
·With recording function, maximum number of recording points: 12800
·USB communication, RS485 communication
·9~36V (DC/AC)/USB 5V power supply optional
·Built-in alarm function
·Built-in lithium battery (rechargeable)

LCD dual-display communication temperature and humidity controller PT500-GSP885

2、 Product parameters
1. Power supply voltage: 9~36VDC or USB 5V or built-in lithium battery
2. Display resolution: 0.1 ℃ or 0.1% RH
3. Working temperature: - 20~+60 ℃; Accuracy: ± 0.5 ℃
4. Working humidity: 0~99.9% RH; Accuracy: ± 3% RH
5. Sampling period: external power: 2s built-in battery: 5s
6. Record points: 12800 (maximum)
7. Power consumption: external power: ＜ 20mA Lithium battery: ＜ 2mA
8. Sensitivity attenuation value: temperature ＜ 0.1 ℃; Humidity ＜ 0.1% RH
9. Battery working time: ≥ 60 days
10. Output signal: RS485 signal
11. Communication protocol: standard MODBUS RTU protocol

3、 Product installation and wiring instructions
Installation method of PT500-GSP885
1. Connect the four wires at the transmitter end of the 4-core (or shielded) connecting cable to the 1, 2, 3, and 4 pins of the transmitter connector (the shielded layer with shielded wire is connected to the power ground);
2. The other end is connected to the power supply and computer (requiring RS485 converter) or other corresponding equipment;
3. Fasten the front and rear housings of the transmitter;
4. Connect the power supply after checking the wiring is correct, and check whether the transmitter output is normal;
5. Now the transmitter can work normally;
6. If external alarm is required, please connect according to RS485 typical application diagram

Switch on/off function description: press and hold the up key to open the switch on/off interface, select ON and press the OK key to shut down the instrument; To restart, press any key, and the recorded data will not be lost. (Stop recording data after shutdown)
Reset key description: open the rear cover of the instrument to see the reset key sign (RESET); If necessary
You can press the built-in reset key with a toothpick or a long and thin object.
Alarm description: When the alarm condition is reached, the built-in alarm will alarm
If you press any of the keys during the alarm, the built-in alarm will be turned off temporarily;
If the user does not make any treatment, the built-in alarm will return to alarm after about 10 seconds.
Description for viewing the recorded points: open the menu selection key, press the key 9 times, switch to the interface between C.01 and C.04, and you can see the recorded points.

Unlock and lock screen
When there is no operation, the screen will be locked within 15 seconds.
In the lock screen state, press and hold the "Confirm" key to unlock.

Recording mode: when the recording mode is set to 0n mode, the transmitter's internal automatic recording data function is turned on to automatically record real-time monitoring data, and the internal recording data can be read through relevant software; When set to 0ff mode, the function of internal recording data is turned off; When set to Auto mode, the intelligent data recording function is started, and the monitoring system terminal monitoring software starts the data recording mode; If there is no equipment to record data, the transmitter will resume the internal automatic data recording function after 10 seconds.
Storage mode: "cyclic storage" refers to that when the internal storage capacity is exhausted, the system continues to store the recorded data repeatedly, overwriting the original stored data for cyclic storage; "Sequential storage" means that when the internal storage capacity is exhausted, the system stops storing the recorded data.
Recording period: the time period during which the monitoring data is recorded within the normal range.
Alarm recording period: the recording period when the monitoring data exceeds the upper and lower limit of the alarm.
Screen backlight switch: there are three modes: normally open, normally closed and delay (30s).
Screen backlight level: There are five levels: 1/2/3/4/5, of which 1 is the brightest and 5 is the darkest.

6、 Example of secondary development communication reading instruction
Note: [1 For detailed communication instructions, please download the detailed product manual.
Format of message sent by host: 01 03 00 00 00 02 C40B The following table is the introduction of function codes:

Note: For details of calculation, please refer to CRC verification introduction later. Due to different addresses, it is necessary to recalculate CRC
＊ Temperature and humidity output format
The temperature and humidity resolution is 16BIT. The temperature and humidity are output in the actual positive and negative number format, and the string value is 10 times the actual temperature and humidity value.

＊ Numerical calculation:
The temperature and humidity value read back from the sensor only needs to convert the value into decimal number (the calculator value in the computer can be directly converted), and then divide by 10 to get the corresponding temperature and humidity value. The corresponding temperature unit is ℃, and the humidity unit is% RH
For example, the data read back above:
Humidity:
01D7=1x256+13x16+7=471 Humidity value=471 ÷ 10=47.1% RH
Temperature:
00D6=13x16+6=214 Temperature value=214 ÷ 10=21.4 ℃

* Calculation method of CRC code:

1. Preset one 16-bit register as hexadecimal FFFF (that is, all are 1); Call this register CRC register;
2. The first 8-bit binary data (i.e. the first byte of the communication information frame) is different from the lower 8 bits of the 16-bit CRC register, and the result is placed in the CRC register;
3. Move the contents of CRC register to the right by one bit (towards the low bit) and fill the highest bit with 0, and check the shift out bit after the right shift;
4. If the shift out position is 0: repeat step 3 (move one position right again); If the shift bit is 1: CRC register and polynomial A001 (1010 00000000000 1) are XOR;
5. Repeat steps 3 and 4 until it is shifted 8 times to the right, so that the entire 8-bit data has been processed;
6. Repeat steps 2 to 5 to process the next byte of the communication information frame;
7. After all bytes of the communication information frame are calculated according to the above steps, the high and low values of the 16-bit CRC register are obtained
Bytes are exchanged;
8. The final CRC register is CRC code.
7、 Temperature and humidity measurement error curve

Each measured value of the product may be affected by the following factors:
1. Temperature error
The stabilization time is too short in the test environment.
Close to heat source, cold source, or directly under the sun.
2. Humidity error
The stabilization time is too short in the test environment.
It is forbidden to be exposed to steam, water mist, water curtain or condensation for a long time.
3. Pollution
In dust or other polluted environment, the product must be cleaned regularly.