OpenIGTLink/ProtocolV2/Type/SensorData

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Summary

SDATA is a message type, which is used to transfer sensor reading, 3-axis position, velocity, acceleration, angle, angle velocity and angle acceleration. The message format is intended for manipulator control and various types of sensors.

Message Types

SENSOR

Data	Type	Description
NSENSORS	uint16	Number of sensors
FORMAT 0
LARRAY 0	uint8	Length of array (0-255)
PREFIX 0	int8	SI-prefix (-127 - 128) (see bellow)
DIMENSION 0	uint8[6]	Dimension (see bellow)
NAME 0	char[20]	Name
...
FORMAT (NSENSORS-1)
LARRAY (NSENSORS-1)	int8	Length of array (0-255)
PREFIX (NSENSORS-1)	int8	SI-prefix (-127 - 128) (see bellow)
DIMENSION (NSENSORS-1)	uint8[6]	Dimension (see bellow)
NAME (NSENSORS-1)	char[20]	Name
DATA
DATA 0	float64[LARRAY 0]	value array for sensor 0
DATA 1	float64[LARRAY 1]	value array for sensor 1
...
DATA (NSENSORS-1)	float64[LARRAY (NSENSORS-1)]	value array for sensor (NSENSORS-1)

Definition of PREFIX and DIMENSION fields

The PREFIX and DIMENSION fields are used to specify units. The PREFIX fields is an exponent representing SI prefix (e.g. milli, micro, nano, kilo, ...), while DIMENSIONS is combination of SI base units and/or SI-delived units.

PREFIX

Value	SI-prefix	Value	SI-prefix
0x01	deka (deca) (1e1)	0xFF	deci (1e-1)
0x02	hecto (1e2)	0xFE	centi (1e-2)
0x03	kilo (1e3)	0xFD	milli (1e-3)
0x06	mega (1e6)	0xFA	micro (1e-6)
0x09	giga (1e9)	0XF7	nano (1e-9)
0x0C	tera (1e12)	0XF4	pico (1e-12)
0x0F	peta (1e15)	0XF1	femto (1e-15)
0x12	exa (1e18)	0XEE	atto (1e-18)
0x15	zetta (1e21)	0XEB	zepto (1e-21)
0x18	yotta (1e24)	0XE8	yocto (1e-24)
0x00	None	--	--

DIMENSION

DIMENSION can consist of up to 6 unit (either SI base unit or SI derived unit) with exponents (-3 - +3)

     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |  UNIT0  | EXP0|  UNIT1  | EXP1|  UNIT2  | EXP2|  UNIT3  | EXP3|  UNIT4  | EXP4|  UNIT5  | EXP5|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
byte 0               1               2               3               4               5

UNIT

UNIT0 - UNIT5 should be either one of SI base units or SI derived units shown bellow.

SI base units

Value	SI base unit name	Value	SI base unit name
0x01	meter	0x05	kelvin
0x02	gram	0x06	mole
0x03	second	0x07	candela
0x04	ampere	--	--

SI derived units

Value	Unit name	dimension	Value	Unit name	dimension
0x08	radian	meter/meter	0x12	ohm	meter^2-kilogram/second^3-ampere^2
0x09	steradian	meter^2/meter^2	0x14	siemens	second^3-ampere^2/meter^2-kilogram
0x0A	hertz	/second	0x15	weber	meter^2-kilogram/second^2-ampere
0x0B	newton	meter-kilogram/second^2	0x16	tesla	kilogram/second^2-ampere
0x0C	pascal	kilogram/meter-second^2	0x17	henry	meter^2-kilogram/second^2-ampere^2
0x0D	joule	meter^2-kilogram/second^2	0x18	lumen	candela-steradian
0x0E	watt	meter^2-kilogram/second^3	0x19	lux	candela-steradian/meter^2
0x0F	coulomb	second-ampere	0x1A	becquerel	/second
0x10	volt	meter^2-kilogram/second^3-ampere	0x1B	gray	meter^2/second^2
0x11	farad	second^4-ampere^2/meter^2-kilogram	0x1C	sievert	meter^2/second^2

Examples

Sending 3-axis position

A device with 3-axis force (N), 3-axis torque (N*m) and 3-axis acceleration (mm/s^2) sensors is sending data to a data logger program. The names of the sensors are "FORCE", "TORQUE", and "ACCEL." The message structure may be as follows:

Data	Type	Value
NSENSORS	uint16	3
LARRAY 0	uint8	3
PREFIX 0	int8	0
DIMENSION 0	uint8[6]	0x58 0x00 0x00 0x00 0x00 0x00 (N)
NAME	char[20]	"FORCE"
LARRAY 1	uint8	3
PREFIX 1	int8	0
DIMENSION 1	uint8[6]	0x58 0x08 0x00 0x00 0x00 0x00 (N*m)
NAME 1	char[20]	"TORQUE"
LARRAY 2	uint8	3
PREFIX 2	int8	0
DIMENSION 2	uint8[6]	0x08 0x03 0x00 0x00 0x00 0x00 (m/s^2)
NAME 2	char[20]	"ACCEL"
VALUE 0	double[3]	{0.0, 0.0, 0.0}
VALUE 1	double[3]	{0.0, 0.0, 0.0}
VALUE 2	double[3]	{0.0, 0.0, 0.0}

GET_SENSOR

Data

Type

Description

STT_SENSOR

N/A

STP_SENSOR

N/A

RTS_SENSOR

N/A

Implementations

The TDATA message type is implemented in the following source code.

Contributors

Junichi Tokuda, Yuichiro Hayashi