SMCCg | norwegian-subsea

The SMCCg protocol is a modified version of the SMCC protocol. The key difference between SMCC and SMCCg is that SMCCg includes gravity in the z-axis acceleration measurement.

Data:

Roll, pitch, heading
Surge, sway, heave
Surge velocity, sway velocity, heave velocity
x acceleration, y acceleration, z acceleration (including gravity)

Format:

$PSMCCG,±xx.xx, ±yy.yy, ±zzz.z, ±ss.ss, ±ww.ww, ±hh.hh, ±sv.sv, ±sw.sw, ±hv. hv, ±ax.axa, ±ay.aya, ±az.aza*cs<CR><LF>

SMCCg protocol description
FIELD N.	FIELD	DESCRIPTION	UNIT	TYPE	NOTE
0	$PSMCCG	identifier	-	string	Telegram identifier.
1	±xx.xx	roll angle	[deg]	DBL	Sign: Positive (+) is port up, negative (-) is port down. xx.xx : ‘xx' is the integer part of the roll represented by two digits in range [-99,99], ‘.’ is decimal separator and 'xx’ is the fractional part of the roll represented by two positive digits in range [0,99].
2	±yy.yy	pitch angle	[deg]	DBL	Sign: Positive (+) is bow down, negative is (-) bow up. yy.yy: ‘yy' is the integer part of the pitch represented by two digits in range [-99,99], ‘.’ is decimal separator and 'yy’ is the fractional part of the pitch represented by two positive digits in range [0,99].
3	±zzz.z	heading angle	[deg]	DBL	Heading increase in clockwise direction. zzz.z: ‘zzz' is the integer part of the heading represented by three positive digits in range [0,359], ‘.’ is decimal separator and 'z’ is the fractional part of the heading represented by one positive digit in range [0,9].
4	±ss.ss	surge	[m]	DBL	Sign: Positive (+) is forward (bow direction), negative (-) is backward (stern direction). ss.ss: ‘ss' is the integer part of the surge represented by two digits in range [-99,99], ‘.’ is decimal separator and 'ss’ is the fractional part of the surge represented by two positive digits in range [0,99].
5	±ww.ww	sway	[m]	DBL	Sign: Positive (+) is starboard right, negative (-) is port left. ww.ww: ‘ww' is the integer part of the sway represented by two digits in range [-99,99], ‘.’ is decimal separator and 'ww’ is the fractional part of the sway represented by two positive digits in range [0,99].
6	±hh.hh	heave	[m]	DBL	Sign: Positive (+) is upward w.r.t reference plane, negative (-) is downward w.r.t reference plane. hh.hh: ‘hh' is the integer part of the heave represented by two digits in range [-99,99], ‘.’ is decimal separator and 'hh’ is the fractional part of the heave represented by two positive digits in range [0,99].
7	±sv.sv	surge velocity	[m/s]	DBL	Sign: Positive (+) is forward (bow direction), negative (-) is backward (stern direction). sv.sv : ‘sv' is the integer part of the surge velocity represented by two digits in range [-99,99], ‘.’ is decimal separator and 'sv’ is the fractional part of the surge velocity represented by two positive digits in range [0,99].
8	±sw.sw	sway velocity	[m/s]	DBL	Sign: Positive (+) is starboard right, negative (-) is port left. sw.sw: ‘sw' is the integer part of the sway velocity represented by two digits in range [-99,99], ‘.’ is decimal separator and 'sw’ is the fractional part of the sway velocity represented by two positive digits in range [0,99].
9	±hv.hv	heave velocity	[m/s]	DBL	Sign: Positive (+) is upward w.r.t reference plane, negative (-) is downward w.r.t reference plane. hv.hv: ‘hv' is the integer part of the heave velocity represented by two digits in range [-99,99], ‘.’ is decimal separator and 'hv’ is the fractional part of the heave velocity represented by two positive digits in range [0,99].
10	±ax.axa	acceleration x	[m/s²]	DBL	Sign: Positive (+) is forward (bow direction), negative (-) is backward (stern direction). ax.axa: ‘ax' is the integer part of the acceleration (x) represented by two digits in range [-99,99], ‘.’ is the decimal separator and 'axa’ is the fractional part of the acceleration (x) represented by three positive digits in range [0,999].
11	±ay.aya	acceleration y	[m/s²]	DBL	Sign: Positive (+) is starboard right, negative (-) is port left. ay.aya: ‘ay' is the integer part of the acceleration (y) represented by two digits in range [-99,99], ‘.’ is the decimal separator and 'aya’ is the fractional part of the acceleration (y) represented by three positive digits in range [0,999].
12	±az.aza	acceleration z (including gravity)	[m/s²]	DBL	Sign: Positive (+) is downward, negative (-) is upward. az.aza: ‘az' is the integer part of the acceleration (z) represented by two digits in range [-99,99], ‘.’ is the decimal separator and 'aza’ is the fractional part of the acceleration (z) represented by three positive digits in range [0,999].
13	CS	checksum	-	HEX	XOR of characters between $ and *

Example:

SMCC frame with raw example data is listed below.

$PSMCC,+00.28,-02.08,+106.0,-00.30,+00.08,-00.17,-00.06,+00.01,-00.02,- 00.365,-00.046,-09.813*70<CR><LF>

Field 0	Field 1	Field 2	Field 3	Field 4	Field 5	Field 6	Field 7	Field 8	Field 9	Field 10	Field 11	Field 12	Field 13
PSMCCG	+00.28	-02.08	+106.0	-00.30	+00.08	-00.17	-00.06	+00.01	-00.02	-00.365	-00.046	-09.813	70

Decoded values:

Roll
- Raw value: +00.28, decoded roll angle: 0.28 degrees
Pitch
- Raw value: -02.08, decoded pitch angle: 2.08 degrees
Heading
- Raw value: +106.0, decoded heading angle: 106.0 degrees
Surge
- Raw value: -00.30, decoded surge: -0.3 m
Sway
- Raw value: +00.08, decoded sway: 0.08 m
Heave
- Raw value: -00.17, decoded heave: -0.17 m
Surge velocity
- Raw value: -00.06, decoded surge velocity: 0.06 m/s
Sway velocity
- Raw value: +00.01, decoded sway velocity: 0.01 m/s
Heave velocity
- Raw value: -00.02, decoded heave velocity: -0.02 m/s
Acceleration x
- Raw value: -00.365, decoded acceleration x: -0.365 m/s²
Acceleration y
- Raw value: -00.046, decoded acceleration y: -0.046 m/s²
Acceleration z
- Raw value: -09.813, decoded acceleration z: -9.813 m/s²
Checksum
- Created from XOR operations of characters between $ and * in the example frame.

Note 1

The fields of data (e.g., ‘xx.xx’) are decimal numbers with leading zeroes where appropriate.

Note 2

The reference frame for data (e.g., roll) is configurable in the SMCCg protocol. Also, the data's location (e.g., MRU or MP1) is configurable.