Users Manual

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LSN50 LoRa Sensor Node User Manual 19 / 55
2.3.5 MOD=5(Weight Measurement by HX711)
This mode is supported in firmware version since v1.6.2.
Notes about hardware connection:
1) Don’t connect the HX711 module VCC to LSN50 3.3v VCC, in this case, the LSn50 will always
power on HX711 and the battery will run out soon.
2) HX711 support 5v VCC, but while connect the LSN50’s +5V to HX711 VCC, the value from
HX711 is not stable.
3) Connect LSn50 +5V to HX711 VCC via a LDO module is stable.
Each HX711 need to be calibrated before used. User need to do below two steps:
a) Zero calibration. Don’t put anything on load cell and run AT+WEIGRE to calibrate to Zero
gram.
b) Adjust calibration factor (default value 400): Put a known weight thing on load cell and run
AT+WEIGAP to adjust the Calibration Factor.
For example:
AT+WEIGAP =403.0
Response: Weight is 401 g
Check the response of this command and adjust the value to match the real value for thing.
Size(bytes)
2
2
2
1
2
2
Value
BAT
Temperature
(DS18B20)
ADC
Digital in & Digital
Interrupt
Weight
Reserved