Supplemental Sensors
Common Commands and Messages
A tilt sensor and gyro are integrated in the Crescent V100/
V110. The user can turn either on or off. However, the
system’s performance is optimized with both on.
Purpose
$JDIFF
Differential mode
$JWAASPRN
Configure for specific SBAS PRN numbers
Query for current location and satellites
GYRO AID
TILT AID
$JGEO
Smooth rate of turn:
-Provides alternate
source of heading for
up to 3 minutes
when GPS lock is lost
-Smooths rate of
heading
-Reduces startup
and
reacquisition
times for
obtaining
heading
$JASC,D1
Request SBAS diagnostic information
$GPMSK
Tune beacon to specific frequency
-Shortens
heading
reacquisition
time
Calibration
Procedure
Differential Commands
Will self-calibrate after
several minutes
To manually calibrate:
-After heading is
computed
-$JATT,GYROAID,YES
-Spin Vector for 1
minute at less than
15o per second
-Leave unit stationary
for 4 minutes
**It is not necessary
to recalibrate with
standard use because
the gyro selects the
calibration.
Precalibrated
during
manufacture
To recalibrate:
-Ensure Vector is
level
-$JATT,TILTCAL
Serial Port Setting Commands
$JBAUD
RS-232C, RS-422 (output) communication rate
Crescent V100 Series
Quick Reference Guide
(Part Number 875-0185-000 Rev. A1)
NMEA Messages
$GPGGA
GPS fix data
$GPGLL
Geographic position - lat/long
$GPGSA
GNSS DOP and active satellites
$GPGSV
GNSS satellites in view
$GPVTG
COG and ground speed
$GPZDA
Time and date
$GPHDG
Provides magnetic deviation and variation for
calculating magnetic or true heading
$GPHDT
RTK-derived GPS heading
$GPROT
RTK-derived GPS Rate of Turn
$PCSI,1
Beacon status
$PSAT,HPR
Heading, pitch/role and time in single message
$GPHDM
Magnetic heading (based on RTK-derived GPS and
magnetic declination)
$J4STRING
Output GPGGA, GPVTG, GPGSA and GPZDA (1 Hz max)
Heading Parameter
$JATT,TILTAID
Enable/disable accelerometer,
pre-calibrated
$JATT,TILTCAL
Calibrate accelerometer
$JATT,GYROAID
Enable/disable gyro
$JATT,LEVEL
Enable/disable level operation
$JATT,HTAU
Set/query heading time constant (0.0 to 3600.0 sec)
$JATT,PTAU
Set/query pitch time constant (0.0 to 3600.0 sec)
$JATT,HRTAU
Set/query heading rate time constant (0.0 to 3600.0 sec)
$JATT,COGTAU
Set/query COG time constant (0.0 to 3600.0 sec)
$JATT,SPDTAU
Set/query speed time constant (0.0 to 3600.0 sec)
$JATT,HBIAS
Set/query heading bias (-180.0° to +180.0°)
$JATT,PBIAS
Set/query pitch/roll bias (-15.0° to +15.0°)
$JATT,NEGTILT
Enable/disable negative tilt
$JATT,ROLL
Configure for roll or pitch
$JATT,NMEAHE
Changes the HDT, ROT, HDG and HDM message
headers between GP and HE (or HC)
www.hemispheregps.com
Crescent V100 - DGPS
Crescent V110 - DGPS + Beacon
Installation
Wiring Interface
Choose a location for installation using either the pole or
fixed mount where the Crescent V100/V110:
•
Has a clear view of the sky
•
Is away from other antennas and electrical
equipment
•
Has enough cable to reach power source
•
Is horizontal
Refer to the Crescent V100 Series User Guide for detailed
installation instructions.
Configuration
Information for the 15 meter cable (part number
051-0157-002) and 30 meter cable (part number
051-0158-001) is shown in the table below.
Use a terminal program, or PocketMAX, to connect to a
serial port for additional configuration requirements. Use
default baud rate of 19,200 bps and 8-N-1 protocol.
Port
Baud
rate
NMEA message
Default
update
rate
Wires
•
Port A
(RS-232)
19200
GPGGA, GPVTG,
GPGSV, GPZDA,
GPHDT, GPROT
1 Hz
BLUE
BLACK with BLUE
Port B
(RS-232)
19200
GPGGA, GPVTG,
GPGSV, GPZDA,
GPHDT, GPROT
1 Hz
BROWN
BLACK with BROWN
Change baud rate of either port to match that of the
external equipment to which the Crescent V100 will
be connected. After the baud rate is changed, you
will need to close the terminal program and
reconnect at the speed selected. The available baud
rates are 4800, 9600, 19200 or 38400.
•
Port A
(RS-422)
19200
GPGGA, GPVTG,
GPGSV, GPZDA,
GPHDT, GPROT
1 Hz
GREEN
BLACK with GREEN
Configure NMEA messages to be output on the
appropriate port.
•
Port B
(RS-422)
19200
GPGGA, GPVTG,
GPGSV, GPZDA,
GPHDT, GPROT
1 Hz
YELLOW
BLACK with YELLOW
Select differential source. (BEACON is the default on
the Crescent V110).
•
Input heading bias (-180° to +180°) to compensate
for any offset from the centerline.
•
Input bias for tilt (-15° to +15°) to compensate for
any offset from horizontal.
•
Enable/disable supplementary sensors (default is
GYROID and TILTAID on).
•
Use the $JSAVE command to save the configuration
changes when finished.
A2
A1
Power
10 – 36 V
Red (+)
Black (-)
Pitch Installation
To provide heading and pitch, mount
parallel to boat’s axis, facing bow.
Recessed arrow
located on bottom of
enclosure
A2
A1
Serial Port Connection
Connect the wires to a DB9 female socket using either the
port A or port B configuration.
Port A DB9 RS-232 interface configuration
Pin
Wire Color
Signal
2
Blue
Port A transmit RS-232
3
Black/blue striped
Port A receive RS-232
5
Grey
Signal ground
Port B DB9 RS-232 interface configuration
Roll Installation
To provide heading and roll, mount perpendicular to
boat’s axis. Configure a bias heading of +90° if facing
port or -90° if facing starboard.
Pin
Wire Color
Signal
2
Brown
Port B transmit RS-232
3
Black/brown striped
Port B receive RS-232
5
Grey
Signal ground
DB9 female socket numbering
•
A1: Primary antenna determines your position
•
A2: Secondary antenna determines pitch or roll
(enter 90° bias if using roll set-up)
5 4 3 2 1
9 8 7 6
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