Keep-alive

Keep-alive command explanation

Periodically sent message which contains the most important device data.

For this device, the default keep-alive period is 240 minutes.

The data is described in Table 2. In Table 3 example packet is given.

Byte index	Bit index	Meaning
0	-	Command byte for this packet.
1	-	Battery voltage, [mV] = XX * 8 + 1600.
2	7:4	Reserved.
2	3	The measured temperature: 1: Is negative; 0: Is positive.
2	2	Thermistor operational status: 1: Thermistor connection is broken; 0: The thermistor is connected.
2	1:0	Thermistor temperature data, bits [9:8].
3	7:0	Thermistor temperature data, bits [7:0]. The measurement resolution is 0.1 °C. t,[°C]= 10 T[9:0].
4	-	Event counter Unsigned value, range 0 – 16,777,215. Bits[23:16]
5	-	Bits [15:8]
6	-	Bits [7:0]
7	7:1	Reserved.
	0	Sensor status: 1: Open; 0: Closed.

Table 2

Payload index	Value, [hex]	Bit index	Meaning
0	01	-	Keep-alive
1	AB	-	Battery voltage, [mV] = 171 * 8 + 1600 = 2968.
2	00	7:4	Reserved.
		3	The measured temperature. 0: Is positive.
		2	Thermistor operational status. 0: The thermistor is connected.
		1:0	Thermistor temperature data, bits [9:8] is 0.
3	D9	-	Thermistor temperature data, bits [7:0] t = D9 / 10 = 217 / 10 = 21.7 °C.
4	1B	-	Count, [HEX]: 1B5CAE. The hex value convert to decimal =>1 793 198. Bits[23:16]
5	5C	-	Bits [15:8]
6	AE	-	Bits [7:0]
7	01	7:1	Reserved.
		1	Sensor status. 1: Open.

Table 3

Set keep-alive period command explanation

Sets the period of the device keep-alive command messages. See table 4 for details.

Byte index	Bit index	Hex value – Meaning
0	-	02 – The command will set the device keep-alive period.
1	-	XX – keep-alive period in minutes. Value 00 isn’t applicable. Default value: 240min.

Table 4

Example command, [Hex]: 020A

The example sets the keep-alive period to 10 minutes.

Note that the keep-alive period must respect the LoRaWAN messages duty cycle limitations. Otherwise the message will be sent when this is allowed. Also, the bigger keep-alive period, the less battery discharge.

Get keep-alive period command explanation

This command is used to get the device keep-alive command messages period. Server sends the command code and the response is sent from the device together with next keep-alive command. The sent command request and the received command response are described in Table 6. The keep-alive in the response is omitted for clarity.

Byte index	Sent request, [hex]	Received response, [hex]
0	12 – The command code.	12 – The command code.
1		XX – device keep-alive period in minutes.

Table 5

Example command sent from server, [Hex]: 12;

Example command response, [Hex]: 120A – Device keep-alive period is 10 minutes.