Q1: Why the AM307 TVOC value have a distinct difference after reset?

Answer: For AM300 series, it will automatically calibrate every 28 days by default. And when you reset whole sensor, it will re-invoke to TVOC factory calibration baseline as 25, which is different with the auto calibration baseline. That's why TVOC value will change to the difference value after reset.

Q2: When putting the AM319 in a small bedroom with door and window closed all night during sleep, the CO2 value will goes more than 5000 ppm in the morning, and will drop to 500 ppm after open window and door for ventilation in the morning, is that reasonable?

Answer:  Yes, in a small and confined space with people stay for several hours, the CO2 value may spikes to a high level. So it’s suggested not to close windows or doors for long time, which may affect the health.

Q3: For AM319, can I sync sensor time via both toolbox and remotely?

Answer:  Yes, both can support. For toolbox, You can connect sensor via Toolbox and go to Status page, click Sync button to Sync time. For remotely control, You can send a downlink command as Hex type like below for set sensor time.


7e050c00 0b a1a39062 6400 7e

Current timestamp: 1653646241 ;to hex: 6290a3a1 Invert order: a1a39062

Current timezone:GMT+10 -> 100; to hex: 0064; Invert order: 6400

Q4: Why there is decode error when connecting Milesight Sensor to TTN network server?

Answer: Please check the LoRaWAN version parameter, it's recommended to set LoRaWAN version as 1.0.2 or 1.0.3 both in TTN and sensor. 

Q5: Why it never ask to verify the password after change the password of sensor via ToolBox App?

Answer: There are possible reasons:

  1. When using the Toolbox App, it will only ask to verify when writing configuration but not read.

  2. Your mobile phone will save the changed password and do not ask for password again, you can use another phone to write the configuration to check if password changes.

Q6: Can the probe of EM500-PT100 be dipped in molten liquid in Aluminium process industry?

Answer: No suggested since the working temperature of default connecting wire is only between -200 and 290 ℃. If you need higher temperature, this needs to customize other kind of cable materials.

Q7: Is an external antenna possible on the EM500-UDL?

Answer: Not support yet, EM500-UDL uses a built-in antenna. If you need to connect an external antenna, it needs hardware customization. If you have project or requirements, please contact Milesight about it.

Q8: If we mount the EM310-UDL in a pipe dimeter 120 mm, will this work with the ultrasonic waves? 

Answer: No, EM310-UDL needs to be at least more than 30 cm away from side walls, otherwise sound waves will reflect and cause measurement errors.

Q9: Can Milesight sensor support GSM?

Answer: Not support, but if you have tradiontial sensors with serial ports or analog outputs, it’s suggested to use UC300 cellular controller supporting GSM.


1.Can the EM500-SWL test atmospheric pressure? 

2.When testing the liquid level, does EM500-SWL need to be suspended in the air or does it need to reach the bottom of the liquid for testing?


1.No, EM500-SWL can just test the liquid level.

2.It requires the sensor probe to reach the bottom of the liquid for testing.


1. Is it possible to send LoRaWAN sensor alarms via https strings?

2. Do the temperature change alarms for example of the EM300 arrive in real time or do you 

have to wait for the reporting interval refresh?


1. Yes, if you use Milesight gateway built-in NS which equips with HTTP/HTTP API, you can send the packet to third part server via http/https.

2.If you set a threshold alarm, when the detection value exceeds the threshold, it will be reported immediately.

Q12: How can I disable the screen display of AM319?

Answer: Please disable the display option on ToolBox.