HWT31 Protocol

HWT31 Protocol

Instructions for use：

Enter commands that need to modify or read data

Read format

• Data is sent in hexadecimal, not ASCII.

• Each data is transmitted in sequence by low byte and high byte, and the two are combined into a signed short type of data. For example, for data DATA1, DATA1L is the low byte and DATA1H is the high byte. The conversion method is as follows: Suppose DATA1 is the actual data, DATA1H is its high-byte part, DATA1L is its low-byte part,

Then: DATA1=(short)((short)DATA1H<<8|DATA1L). It must be noted here that DATA1H needs to be coerced into a signed short type of data before shifting, and the data type of DATA1 is also a signed short type, so that negative numbers can be represented.

Protocol header	Data content	Data lower 8 bits	Data high 8 bits	Data lower 8 bits	Data high 8 bits	Data lower 8 bits	Data high 8 bits	Data lower 8 bits	Data high 8 bits	SUMCRC
0x55	TYPE【1】	DATA1L[7:0]	DATA1H[15:8]	DATA2L[7:0]	DATA2H[15:8]	DATA3L[7:0]	DATA3H[15:8]	DATA4L[7:0]	DATA4H[15:8]	SUMCRC【2】

【1】TYPE(data content):

TYPE	Remark
0x51	Acceleration
0x53	Angle

【2】SUMCRC(Data and Checksum)：

SUMCRC=0x55+TYPE+DATA1L+DATA1H+DATA2L+DATA2H+DATA3L+DATA3H+DATA4L+DATA4H

SUMCRC is a char type, taking the lower 8 bits of the checksum

Acceleration output

0x55	0x51	AxL	AxH	AyL	AyH	AzL	AzH	TL	TH	SUM
Name	Description	Remark
AxL	Acceleration X low 8 bits	Acceleration X=((AxH<<8)|AxL)/32768*16g (g is the acceleration of gravity, preferably 9.8m/s2)
AxH	Acceleration X high 8 bits
AyL	Acceleration Y low 8 bits	Acceleration Y=((AyH<<8)|AyL)/32768*16g (g is the acceleration of gravity, preferably 9.8m/s2)
AyH	Acceleration Y high 8 bits
AzL	Acceleration Z low 8 bits	Acceleration Z=((AzH<<8)|AzL)/32768*16g (g is the acceleration of gravity, preferably 9.8m/s2)
AzH	Acceleration Z high 8 bits
TL	8-bit lower temperature	Temperature calculation formula: temperature=((TH<<8)|TL) /100 ℃
TH	8-bit high temperature
SUM	Checksum	SUM=0x55+0x51+AxL+AxH+AyL+AyH+AzL+AzH+TL+TH

Angle output

0x55	0x53	RollL	RollH	PitchL	PitchH	0x00	0x00	TL	TH	SUM
Name	Description	Remark
RollL	Roll angle X lower 8 bits	roll angle X=((RollH<<8)|RollL)/32768*180(°)
RollH	Roll angle X high 8 bits
PitchL	Pitch angle Y low 8 bits	Pitch angle Y=((PitchH<<8)|PitchL)/32768*180(°)
PitchH	Pitch angle Y high 8 bits
0x00	meaningless	meaningless
0x00	meaningless
VL	The lower 8 bits of the version number	Version number calculation formula: Version number=(VH<<8)|VL
VH	Version number high 8 bits
SUM	Checksum	SUM=0x55+0x53+RollL+RollH+PitchL+PitchH+VL+VH

Write format

• The following data, all use Hex code hexadecimal

protocol header	protocol header	register	Data lower 8 bits	Data high 8 bits
0xFF	0xAA	ADDR	DATAL[7:0]	DATAH[15:8]

• The data is sent in hexadecimal not ASCII.

• Each data is transmitted in sequence by low byte and high byte, and the two are combined into a signed short type of data. For example, data DATA, where DATAL is the low byte and DATAH is the high byte. The conversion method is as follows: assuming that DATA is the actual data, DATAH is the high byte part, DATAL is the low byte part,

Then: DATA=(short)((short)DATAH<<8|DATAL). It must be noted here that DATAH needs to be coerced into a signed short type of data before shifting, and the data type of DATA is also a signed short type, so that negative numbers can be represented.

CALSW（Calibration mode）

Register Name: CALSW Register Address: 1 (0x01) Read and write direction: W Default: 0x0000
Bit	NAME	FUNCTION
15:1
0:0	CAL	To set the calibration mode: 1(0x01): Addition calibration
Example: FF AA 01 01 00 (plus calibration)

BAUD（Serial port baud rate）

Register Name: BAUD Register Address: 4 (0x04) Read and write direction: W Default: 0x0000
Bit	NAME	FUNCTION
15:1
0:0	BAUD	Set the serial port baud rate: 0(0x00): 115200bps 1(0x01): 9600bps
Example：FF AA 04 00 00（Set the serial port baud rate115200）

DELAYT（Alarm signal delay）

Register Name: DELAYT Register Address: 89 (0x59) Read and write direction: W Default: 0x0000
Bit	NAME	FUNCTION
15:0	DELAYT[15:0]	Unit: ms After the angle alarm occurs, the port will generate a corresponding alarm signal. When the alarm disappears, the alarm signal will continue to delay DELAYT[15:0] before disappearing.
Example：FF AA 59 E8 03（Set the alarm signal delay1000ms）

XMIN~XMAX（X-axis angle alarm threshold）

Register Name: XMIN~XMAX Register address: 90~91 (0x5A~0x5B) Read and write direction: W Default: 0x0000
Bit	NAME	FUNCTION
15:0	XMIN[15:0]	Set the X-axis angle alarm minimum value X-axis angle alarm minimum value=XMIN[15:0]*90/32768(°)
15:0	XMAX[15:0]	Set the X-axis angle alarm maximum value X-axis angle alarm maximum value=XMAX[15:0]*90/32768(°)
Example: FF AA 5A 72 FC (set -2.5 degrees), 0xFC72=-910, -910*90/32768=-2.5 FF AA 5B 8E 03 (set 2.5 degrees), 0x038E=910, 910*90/32768=2.5 The X axis will not alarm between -2.5°~2.5°, once it exceeds this range, an alarm will occur

YMIN~YMAX（Y-axis angle alarm threshold）

Register Name: YMIN~YMAX Register address: 94~95 (0x5E~0x5F) Read and write direction: W Default: 0x0000
Bit	NAME	FUNCTION
15:0	YMIN[15:0]	Set the Y-axis angle alarm minimum value Y-axis angle alarm minimum value=YMIN[15:0]*90/32768(°)
15:0	YMAX[15:0]	Set the Y-axis angle alarm maximum value Y-axis angle alarm maximum value=YMAX[15:0]*90/32768(°)
Example: FF AA 5E 72 FC (set -5 degrees), 0xFC72=-910, -910*90/32768=-2.5 FF AA 5F 8E 03 (set 5 degrees), 0x038E=910, 910*90/32768=2.5 The Y axis will not alarm between -2.5°~2.5°, once it exceeds this range, an alarm will occur