Ursalink EM500-SWL, User Manual, Page: 3 / 32

1. Uplink Payload Structure
An uplink message can be sent from EM500-SWL to gateway. Also, the EM500-SWL sends
different sensor data in different frames. In order to do that, all data must be prefixed with two
bytes:
Data Channel: Uniquely identifies each sensor in the EM500-SWL across frames, e.g. "Water
Lever Sensor".
Data Type: Identifies the data type in the frame, e.g. "Battery Level".
The device can send multiple data at one time by using following payload structure:
1 Byte 1 Byte N Bytes 1 Byte 1 Byte M Bytes 1 Byte ...
Channel1 Type1 Data1 Channel2 Type2 Data2 Channel 3 ...
Uplink Packet Example
Frame N: Regular uplink (Water Level)
Frame N+1: Battery level changes uplink.
Frame N+2:
Content will be reported each time when device reboots: Ursalink Custom Format V SN +
Hardware V Software V Class Type
Channel ID Description
1 Battery
2 Reserved
3 Water Level Sensor
03 77 02 00
Channel Type Value
03
(Water Level Sensor)
77
(Water Level)
02 00 => 00 02 = 02 (2 cm)
01 75 64
Channel Type Value
01
(Battery)
75
(Battery Level)
64 =100 means 100%