Q1: When the sensor reconnects to the TTN Network Server, why it keeps received Join-requset however no Join-accept but error message "DevNonce is too small"?

Answer: The error message "DevNonce is too small" happens when using LoRaWAN MAC version 1.0.4 or 1.1, it's recommended to use LoRaWAN MAC version 1.0.3 on Milesight Sensor and TTN settings.

Q2:  What is the difference between EM500-PP-4780 and EM500-PP-4842?

Answer:  The two version probes provide same measurement, accuracy and resolution. EM500-PP-4780 probe works with RS485 Modbus protocol and EM500-PP-4842 works with voltage out, so they are using different pinouts and you can find the details in User Guide:


Q3:  Why the AM319 will switch off and on every 30 minutes?

Answer: It's full-screen refreshing. It will refresh every 30 minutes in order to remove ghosting.

Q4:  For WS156, is it support to switch the image when button is pressed that we can know which scene is activated?

Answer: Not support yet. The WS156 supports e-ink screen display content programming but it's static and can not changed by button press. If you have request about it, please contact Milesight IoT.

Q5:  What is the collecting interval of AM103 temperature, humidity and CO2 value?

Answer: Temperature and humidity are measured every 30 seconds, CO2 is measured every 2 minutes.

Q6:  For AM300 series, why there is a decoder error when connecting to TTN server?

Answer: Please double check the LoRaWAN version of the sensor and TTN settings, it’s recommended to use LoRaWAN version 1.0.2 or 1.0.3 in both sensor and TTN server.

Q7:  Questions about EM300-MCS:

1. Is it possible to track both the temperature value and the door open/close status of refrigerator?

2. With IP67 case, does the temperature sensor of device measure the ambient temperature or case temperature?


1. Yes, EM300-MCS has built-in temperature sensor to monitor refrigerator's temperature and also detect open/close status. But for measure refrigerator temperature, it requires to install the sensor inside of fridge which might affect signal strength if the fridge's material is all mental.

2. It measures the ambient temperature. There is a vent on the bottom of the sensor for ventilation and temperature and humidity measurement, so IP67 case will not affect the detection of ambient temperature.

Q8:  Why it fails to power up the VS121 when using 10 meters extension length USB cable?

Answer: The USB cable have length limitation for power supply, when the length over 5 meters, it’s suggested to use active USB cables or add USB hubs.

Q9:  Questions about AM107:

1. When connecting AM107 to AWS IoT core, why there is decode error?

2. What is the Eirp value of AM107-EU868?


1. Please double check the LoRaWAN version in both sensor and AWS IoT core, it is recommended to use LoRaWAN version 1.0.3 when connecting to AWS IoT core.

2. From this formula, EIRP = TXPower (dBm) + antenna gain (dBi) – cable loss (dB). For AM107, the antenna gain and cable loss on the sensor are negligible, so Eirp is approximately equal to EU868 default TX Power: 16dbm.

Q10:  With threshold configuration set, why the AM319 reports variable length of packet which doesn't look like a complete packet?

Answer: When threshold is triggerred, the sensor will only report the data been triggered. In addition, when setting larger SF value, one packet may be split to two or three parts due to the limitation of packet length.

Q11:  Can the VS121 be powered by the battery in EM500?

Answer: Not support, VS121 is powered by 5V/1.5A type-C port, which does not match EM500 battery which voltage is 3.6V. Besides, VS121 power consumption is too high to use battery powered.

Q12:  Can AM319 send its data to the PLC directly?

Answer: No, AM319 only supports LoRaWAN transmission, but it can transmit data to LoRaWAN gateway and the gateway can forward the data if the PLC supports MQTT/HTTP/TCP, etc.

Q13:  Can the case of EM500 support UV-protection?

Answer: Yes, the case material of EM500 is ABS+PC,which supports UV-protection.

Q14:  For EM300-TILT, can it report the maximum value of angle changes over a period of time?

Answer: Not support yet. It can only report the current specific angle values of the three axes. But you can set a threshold value, when the XYZ angle reaches a certain value, it will report the data immediately.

Q15:  Can the wire of the EM500-PT100 work in 750℃ environment?

Answer: Not supported, if necessary please contact Milesight for special material wire customization.

Q16:  Is WS302 in accordance with Type 2/Class 2 as defined by iso-iec-61672-1 standard?

Answer: No, WS302 belongs to civil noise detection can not work as professional sound level meter, but we have comparison test with a class 1 sound level meter and the accuracy is about 2-3 dB.

Q17:  Can EM500-UDL detect the 90℃ water level?

Answer: Yes, it does not need to touch water directly and supports temperature compensation, which will not affect the detection.