Campbell Gps16x-hvs User manual

GPS16X-HVS

GPS

Receiver

Issued: 5.1.16

Printed under licence by Campbell Scientific Ltd.

CSL 807

USER MANUAL

Guarantee

This equipment is guaranteed against defects in materials and workmanship.

We will repair or replace products which prove to be defective during the

guarantee period as detailed on your invoice, provided they are returned to us

prepaid. The guarantee will not apply to:



Equipment which has been modified or altered in any way without the

written permission of Campbell Scientific



Batteries



Any product which has been subjected to misuse, neglect, acts of God or

damage in transit.

Campbell Scientific will return guaranteed equipment by surface carrier

prepaid. Campbell Scientific will not reimburse the claimant for costs incurred

in removing and/or reinstalling equipment. This guarantee and the Company’s

obligation thereunder is in lieu of all other guarantees, expressed or implied,

including those of suitability and fitness for a particular purpose. Campbell

Scientific is not liable for consequential damage.

Please inform us before returning equipment and obtain a Repair Reference

Number whether the repair is under guarantee or not. Please state the faults as

clearly as possible, and if the product is out of the guarantee period it should

be accompanied by a purchase order. Quotations for repairs can be given on

request. It is the policy of Campbell Scientific to protect the health of its

employees and provide a safe working environment, in support of this policy a

“Declaration of Hazardous Material and Decontamination” form will be

issued for completion.

When returning equipment, the Repair Reference Number must be clearly

marked on the outside of the package. Complete the “Declaration of

Hazardous Material and Decontamination” form and ensure a completed copy

is returned with your goods. Please note your Repair may not be processed if

you do not include a copy of this form and Campbell Scientific Ltd reserves

the right to return goods at the customers’ expense.

Note that goods sent air freight are subject to Customs clearance fees which

Campbell Scientific will charge to customers. In many cases, these charges are

greater than the cost of the repair.

Campbell Scientific Ltd,

80 Hathern Road,

Shepshed, Loughborough, LE12 9GX, UK

Tel: +44 (0) 1509 601141

Fax: +44 (0) 1509 601091

Email: [email protected]

www.campbellsci.co.uk

PLEASE READ FIRST

About this manual

Please note that this manual was originally produced by Campbell Scientific Inc. primarily for the North

American market. Some spellings, weights and measures may reflect this origin.

Some useful conversion factors:

Area: 1 in2(square inch) = 645 mm2

Length: 1 in. (inch) = 25.4 mm

1 ft (foot) = 304.8 mm

1 yard = 0.914 m

1 mile = 1.609 km

Mass: 1 oz. (ounce) = 28.35 g

1 lb (pound weight) = 0.454 kg

Pressure: 1 psi (lb/in2) = 68.95 mb

Volume: 1 UK pint = 568.3 ml

1 UK gallon = 4.546 litres

1 US gallon = 3.785 litres

In addition, while most of the information in the manual is correct for all countries, certain information

is specific to the North American market and so may not be applicable to European users.

Differences include the U.S standard external power supply details where some information (for

example the AC transformer input voltage) will not be applicable for British/European use. Please note,

however, that when a power supply adapter is ordered it will be suitable for use in your country.

Reference to some radio transmitters, digital cell phones and aerials may also not be applicable

according to your locality.

Some brackets, shields and enclosure options, including wiring, are not sold as standard items in the

European market; in some cases alternatives are offered. Details of the alternatives will be covered in

separate manuals.

Part numbers prefixed with a “#” symbol are special order parts for use with non-EU variants or for

special installations. Please quote the full part number with the # when ordering.

Recycling information

At the end of this product’s life it should not be put in commercial or domestic refuse but

sent for recycling. Any batteries contained within the product or used during the

products life should be removed from the product and also be sent to an appropriate

recycling facility.

Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases

arrange collection and the correct disposal of it, although charges may apply for some

items or territories.

For further advice or support, please contact Campbell Scientific Ltd, or your local agent.

Campbell Scientific Ltd, 80 Hathern Road, Shepshed, Loughborough, LE12 9GX, UK

Tel: +44 (0) 1509 601141 Fax: +44 (0) 1509 601091

Email: [email protected]

www.campbellsci.co.uk

Precautions

DANGER —MANY HAZARDS ARE ASSOCIATED WITH INSTALLING, USING, MAINTAINING, AND WORKING ON

OR AROUND TRIPODS, TOWERS, AND ANY ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS,

CROSSARMS, ENCLOSURES, ANTENNAS, ETC. FAILURE TO PROPERLY AND COMPLETELY ASSEMBLE,

INSTALL, OPERATE, USE, AND MAINTAIN TRIPODS, TOWERS, AND ATTACHMENTS, AND FAILURE TO HEED

WARNINGS, INCREASES THE RISK OF DEATH, ACCIDENT, SERIOUS INJURY, PROPERTY DAMAGE, AND

PRODUCT FAILURE. TAKE ALL REASONABLE PRECAUTIONS TO AVOID THESE HAZARDS. CHECK WITH YOUR

ORGANIZATION'S SAFETY COORDINATOR (OR POLICY) FOR PROCEDURES AND REQUIRED PROTECTIVE

EQUIPMENT PRIOR TO PERFORMING ANY WORK.

Use tripods, towers, and attachments to tripods and towers only for purposes for which they are designed. Do not

exceed design limits. Be familiar and comply with all instructions provided in product manuals. Manuals are

available at www.campbellsci.eu or by telephoning +44(0) 1509 828 888 (UK). You are responsible for conformance

with governing codes and regulations, including safety regulations, and the integrity and location of structures or land

to which towers, tripods, and any attachments are attached. Installation sites should be evaluated and approved by a

qualified engineer. If questions or concerns arise regarding installation, use, or maintenance of tripods, towers,

attachments, or electrical connections, consult with a licensed and qualified engineer or electrician.

General

•Prior to performing site or installation work, obtain required approvals and permits. Comply with all

governing structure-height regulations, such as those of the FAA in the USA.

•Use only qualified personnel for installation, use, and maintenance of tripods and towers, and any

attachments to tripods and towers. The use of licensed and qualified contractors is highly recommended.

•Read all applicable instructions carefully and understand procedures thoroughly before beginning work.

•Wear a hardhat and eye protection, and take other appropriate safety precautions while working on or

around tripods and towers.

•Do not climb tripods or towers at any time, and prohibit climbing by other persons. Take reasonable

precautions to secure tripod and tower sites from trespassers.

•Use only manufacturer recommended parts, materials, and tools.

Utility and Electrical

•You can be killed or sustain serious bodily injury if the tripod, tower, or attachments you are installing,

constructing, using, or maintaining, or a tool, stake, or anchor, come in contact with overhead or

underground utility lines.

•Maintain a distance of at least one-and-one-half times structure height, or 20 feet, or the distance

required by applicable law, whichever is greater, between overhead utility lines and the structure (tripod,

tower, attachments, or tools).

•Prior to performing site or installation work, inform all utility companies and have all underground utilities

marked.

•Comply with all electrical codes. Electrical equipment and related grounding devices should be installed

by a licensed and qualified electrician.

Elevated Work and Weather

•Exercise extreme caution when performing elevated work.

•Use appropriate equipment and safety practices.

•During installation and maintenance, keep tower and tripod sites clear of un-trained or non-essential

personnel. Take precautions to prevent elevated tools and objects from dropping.

•Do not perform any work in inclement weather, including wind, rain, snow, lightning, etc.

Maintenance

•Periodically (at least yearly) check for wear and damage, including corrosion, stress cracks, frayed cables,

loose cable clamps, cable tightness, etc. and take necessary corrective actions.

•Periodically (at least yearly) check electrical ground connections.

WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL

SCIENTIFIC PRODUCTS, THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER

INSTALLATION, USE, OR MAINTENANCE OF TRIPODS, TOWERS, OR ATTACHMENTS TO TRIPODS AND TOWERS

SUCH AS SENSORS, CROSSARMS, ENCLOSURES, ANTENNAS, ETC.

Contents

PDF viewers: These page numbers refer to the printed version of this document. Use the

PDF reader bookmarks tab for links to specific sections.

1. Overview.....................................................................1

1.1 Default Settings....................................................................................1

1.2 Compatible Dataloggers.......................................................................2

1.3Common Accessories...........................................................................2

2. Specifications ............................................................3

3. Wiring .........................................................................4

3.1 Using with an A300 .............................................................................5

4. GPS Data....................................................................6

4.1 $GPGGA Sentence (Position and Time)..............................................6

4.2 $GPRMC Sentence (Position and Time) .............................................7

5. CRBasic Programming..............................................8

5.1 GPS() Instruction .................................................................................8

5.2 Example Program Using GPS() Instruction.......................................10

5.3 Example Program Using Serial Instruction........................................11

6. Troubleshooting ......................................................13

6.1 Testing and Evaluating Serial Communications ................................13

6.2 NMEAStrings Variable Populated, but Clock Not Setting ................14

Appendices

A. Changing GPS16X-HVS Settings.......................... A-1

A.1 Computer Connections.................................................................... A-1

A.1.1 Using the A200........................................................................ A-1

A.1.1.1 Driver Installation ......................................................... A-1

A.1.1.2 Wiring ........................................................................... A-2

A.1.1.3 Powering the Sensor...................................................... A-3

A.1.1.4 Determining which COM Port the A200 has been

Assigned .................................................................... A-3

A.1.2 Using the SC110...................................................................... A-3

B. CR23X Wiring and Programming.......................... B-1

B.1 CR23X Connections ........................................................................B-1

B.2 Programming....................................................................................B-1

B.2.1 Program Execution Interval ......................................................B-1

B.2.2 Reading GPS Data ....................................................................B-2

B.2.2.1 CR23X Example of Instruction 15 (P15) .......................B-3

B.2.3 Filters........................................................................................B-3

B.2.4 Managing the Data....................................................................B-3

B.2.5 Program Discussion ..................................................................B-4

B.2.5.1 CR23X Example Program..............................................B-6

B.3 Troubleshooting ...............................................................................B-8

C. Using an SDM-SIO4 ............................................... C-1

C.1 SDM-SIO4 Connections ..................................................................C-1

C.2 CR9000X Example Program ...........................................................C-1

Figures

1-1. The GPS16X-HVS terminates in pigtails for direct connection to

our dataloggers .................................................................................1

3-1. CR1000 to GPS16X-HVS connection .................................................5

A-1. A200 Sensor-to-PC Interface...........................................................A-2

Tables

1-1. Default Settings....................................................................................1

3-1. Datalogger Wiring ...............................................................................4

5-1. GPS16X-HVS Wiring to A300 Terminals and Datalogger

Terminals..........................................................................................5

5-2. A300 Cable Wiring to Datalogger Terminals ......................................6

4-1. NMEA $GPGGA String Definition.....................................................6

A-1. A200 Wiring ....................................................................................A-2

A-2. SC110’s DCE Cable Wiring ............................................................A-3

B-1. CR23X Wiring.................................................................................B-1

B-2. P15 for NMEA $GPGGA Data String.............................................B-2

B-3. Filter.................................................................................................B-3

C-1. SC110’s Cable Wiring.....................................................................C-1

GPS16X-HVS GPS Receiver

1. Overview

Figure 1-1. The GPS16X-HVS terminates in pigtails for direct connection

to our dataloggers

The GPS16X-HVS is a complete GPS receiver manufactured by Garmin

International, Inc. Campbell Scientific configures the GPS16X-HVS to work with

our dataloggers and modifies its cable so that the cable terminates in pigtails. The

pigtails connect directly to the control ports of our dataloggers or with the aid of

an A300.

The GPS16X-HVS includes the GPS receiver and antenna in the same housing

with one cable for the power supply and communications. The GPS antenna must

have a clear view of the sky. Generally the GPS antenna will not work indoors.

The GPS16X-HVS is a 12-channel GPS receiver that supports FAA Wide Area

Augmentation System (WAAS) or RTCM differential GPS. Also supported is the

1 Pulse Per Second (PPS) timing signal. The cable connections provided with the

GPS16X-HVS do not support differential GPS correction. The cable can be

modified by the user if differential correction is required.

1.1 Default Settings

Table 1-1 shows the default settings of the GPSX16-HVS.

Table 1-1. Default Settings

Baud Rate

38400 bps

Parity

N (no parity)

Stop Bit

Sentences Output

GPGGA, GPRMC

PPS

100 ms

GPS16X-HVS GPS Receiver

1.2 Compatible Dataloggers

Compatible Contemporary Dataloggers

CR200(X)

Series

CR800/

CR850

CR1000

CR3000

CR6

CR9000X

See

Appendix

Band C

*If PPS is required, the A300 Power and Signal Converter is needed.

Compatible Retired Dataloggers

CR500

CR510

CR10

CR10X

21X

CR23X

CR9000

CR5000

CR7X

See

Appendix

Band C

See

Appendix

Band C

See

Appendix

Band C

Our CR6, CR800, CR850, CR1000, and CR3000 dataloggers typically use the

CRBasic GPS() instruction to read the GPS16X-HVS. To use the PPS

functionality, some dataloggers need an updated clock chip. The clock chip is

factory replaced (requires an RMA). Dataloggers with the following serial

numbers need an updated chip:

Datalogger

Serial Number

CR1000M

< 20409

CR800, CR850

< 7920

CR3000

< 3168

In August 2014, Garmin changed the GPS16X-HVS PPS output signal from

5 V to 3 V. Units with serial numbers greater than 1A4189318 have a 3 V PPS

output signal. When this new design is used with a CR800, CR850, CR1000, or

CR3000 datalogger, a 3 V to 5 V voltage shifter is required for use with the PPS

signal output. The A300 can be used for this purpose. This level shifter is NOT

required for the CR6 datalogger.

1.3 Common Accessories

CSI part number Description

17212 GPS16X-HVS magnetic mount

CM235 Magnetic mounting stand

A200 Sensor to PC interface

User Manual

2. Specifications

Physical

Size: 86 mm (3.39 in) diameter, 42 mm (1.65 in) high

Weight: 181 g (6.4 oz) without cable, 332 g (11.7 oz) with 5 m

cable

Cable: PVC-jacketed, 5 m, foil-shielded, 8-conductor, 28 AWG

Electrical Characteristics

Input Voltage: 8.0 Vdc to 40 Vdc unregulated

Current Drain: 65 mA @ 12 Vdc

GPS Receiver

Sensitivity: –185 dbW minimum

GPS Performance

Receiver: WAAS enabled; 12 parallel channel GPS receiver

continuously tracks and uses up to 12 satellites, 11 if PPS

is active

Acquisition Times (Approximate)

Reacquisition: Less than 2 s

Hot: 1 s (all data known)

Warm: ~38 s (initial position, time and almanac known, ephemeris

unknown)

Cold: ~45 s

SkySearch: 5 min (no data known)

Sentence Rate: 1 s default; NMEA 0183 output interval configurable from

1 to 900 s in one second increments

Accuracy: GPS Standard Positioning Service (SPS)

Position: Less than 15 m, 95% typical (100 m with selective

availability on)

Velocity: 0.1 knot RMS steady state

DGPS (USCG/RTCM)

Position: 3-5 m, 95% typical

Velocity: 0.1 knot RMS steady state

DGPS (WAAS)

Position: Less than 3 m

Velocity: 0.1 knot RMS steady state

PPS Time: ±1 microsecond at rising edge of PPS pulse (subject to

selective availability)

Dynamics: 999 knots velocity (limited above 60,000 ft, 6g dynamics)

GPS16X-HVS GPS Receiver

Interfaces: True RS-232 output, asynchronous serial input compatible

with RS-232 or TTL voltage levels, RS-232 polarity.

Selectable baud rates (4800, 9600, 19200, 38400)

PPS: 1 Hz pulse, programmable width, 1 microsecond accuracy

Power Control

Off: Open circuit

On: Ground or pull to low logic level < 0.3 volts

Environmental Characteristics

Temperature: –30 to 80 °C operational, –40 to 80 °C storage

3. Wiring

The GPS16X-HVS connects directly to a CR6, CR800, CR850, CR1000, or

CR3000 datalogger (see Table 3-1). However, if PPS is required, the A300 Power

and Signal Converter may be required for use with the CR800/850, CR1000, and

CR3000. See Section 3.1, Using with an A300 (p. 5). The CR6 does not require the

use of an A300.

Refer to Appendix B.1, CR23X Connections (p. B-1), if connecting the receiver to a

CR23X. Our CR5000 and CR9000X connect to the receiver via the SC110 and an

SDM-SIO4 (see Appendix C, Using an SDM-SIO4 (p. C-1)).

If the GPS16X-HVS is to be connected to a computer to change the default

settings, an A200 or SC110 cable is needed (see Appendix A, Changing GPS16X-

HVS Settings (p. A-1)).

Table 3-1. Datalogger Wiring

GPS16X-HVS

Datalogger

Function

Red

12V

Power In

Black

Ground

Power Ground

Yellow

Ground or Control Port

for On/Off control

Power Switch

White

Control Port (Rx)

TXD

Grey

Control Port (Tx)

PPS

Blue

Ground or Control Port

(Tx) for datalogger-based

configuration

Rxdata

Shield

Ground

Shield

User Manual

Figure 3-1. CR1000 to GPS16X-HVS connection

3.1 Using with an A300

In 2014, Garmin changed the pulse-per-second (PPS) output of the GPS16X-HVS

from 5 V to 3 V. Units with a serial number 1A4189318 or greater have a PPS

output of 0 to 3 V. For those units, an A300 is needed to connect the PPS output

to a CR800-series, CR1000, or CR3000 datalogger. Those dataloggers require the

PPS line to have a voltage of 3.8 V or greater.

Table 3-2. GPS16X-HVS Wiring to A300 Terminals

and Datalogger Terminals

GPS16X-HVS

Wire Colour

GPS16X-HVS

Wire Function

A300

Terminal

Datalogger

Red

12 V

12V

Black

Ground

Yellow

Enable

Ground (or

Control Port)

White

TXD (Output)

Control Port (Rx)

Grey

PPS

3.3V IN

Blue

RXD (Input)

Ground

Shield

Ground

GPS16X-HVS GPS Receiver

Table 3-3. A300 Cable Wiring to Datalogger Terminals

A300 Wire Colour

A300 Wire Function

Datalogger

Red

12 V

12V

Black

Ground

Green

5 V Signal Input

Ground

White

5 V Signal Output

Control Port (Tx)

4. GPS Data

The GPS16X-HVS has several data formats available. The GPS16X-HVS is

configured to output the NMEA $GPGGA and $GPRMC time and position string.

It is possible to configure the GPS16X-HVS to output other NMEA strings

including the $GPVTG track made good and ground speed string. See Appendix

A, Changing GPS16X-HVS Settings (p. A-1), for details.

4.1 $GPGGA Sentence (Position and Time)

Sample NMEA $GPGGA data string:

$GPGGA,hhmmss,llll.lll,a,nnnnn.nnn,b,t,uu,v.v,w.w,M,x.x,M,y.y,zzzz*hh<CR><LF>

Table 4-1. NMEA $GPGGA String Definition

Field

Description

$GPGGA

NMEA string identifier

hhmmss

UTC of Position: Hours, minutes, seconds

1111.111

Latitude: Degrees, minutes, thousandths of minutes

N (North) or S (South)

nnnnn.nnn

Longitude: Degrees, minutes, thousandths of minutes

E (East) or W (West)

GPS Quality Indicator: 0 = No GPS, 1 = GPS, 2 =

DGPS

Number of Satellites in Use

v.v

Horizontal Dilution of Precision (HDOP)

w.w

Antenna Altitude in Metres

M = Metres

x.x

Geoidal Separation in Metres

M = Meters. Geoidal separation is the difference

between the WGS-84 earth ellipsoid and mean-sea-

level.

y.y

Age of Differential GPS Data. Time in seconds since

the last Type 1 or 9 Update

zzzz

Differential Reference Station ID (0000 to 1023)

Asterisk, generally used as the termination character

Checksum

Carriage return, line feed characters.

User Manual

Sample $GPGGA output strings:

Cold Start

No satellites acquired, Real Time Clock and Almanac invalid:

$GPGGA,,,,,,0,00,,,,,,,*66

Warm Start

No satellites acquired, time from Real Time Clock, almanac valid:

$GPGGA,235032.0,,,,,0,00,,,,,,,*7D

Warm Start

One satellite in use, time from GPS Real Time Clock (not GPS), no position:

$GPGGA,183806.0,,,,,0,01,,,,,,,*7D

Valid GPS Fix

Three satellites acquired, time and position valid:

$GPGGA,005322.0,4147.603,N,11150.978,W,1,03,11.9,00016,M,-016,M,,*6E

4.2 $GPRMC Sentence (Position and Time)

Example (signal not acquired):

$GPRMC,235947.000,V,0000.0000,N,00000.0000,E,,,041299,,*1D

Example (signal acquired):

$GPRMC,092204.999,A,4250.5589,S,14718.5084,E,0.00,89.68,211200,,*25

Field

Example

Comments

Sentence ID

$GPRMC

UTC Time

092204.999

hhmmss.sss

Status

A = Valid, V = Invalid

Latitude

4250.5589

ddmm.mmmm

N/S Indicator

N = North, S = South

Longitude

14718.5084

dddmm.mmmm

E/W Indicator

E = East, W = West

Speed over ground

0.00

Knots

Course over ground

0.00

Degrees

UTC Date

211200

DDMMYY

Magnetic variation

Degrees

Magnetic variation

E = East, W = West

Checksum

*25

Terminator

CR/LF

GPS16X-HVS GPS Receiver

5. CRBasic Programming

This section describes programming a CR6, CR800, CR850, CR1000, or CR3000.

See Appendix B, CR23X Wiring and Programming (p. B-1), and Appendix C, Using

an SDM-SIO4 (p. C-1), for programming other dataloggers.

CRBasic is used to write programs for the CR6, CR1000, CR3000, CR800, and

CR850 dataloggers. These dataloggers use several instructions to read GPS

output, which is asynchronous serial data.

5.1 GPS() Instruction

The GPS() instruction is available for our CR6, CR800, CR850, CR1000, and

CR3000 dataloggers. It is used along with a GPS device to set the datalogger's

clock. This instruction will also provide information such as location

(latitude/longitude) and speed, and store NMEA sentences from the GPS device.

To use the GPS() instruction, the datalogger operating system (OS)

should be OS17 or higher for the CR1000; OS10 or higher for the

CR3000; or OS08 or higher for the CR800 and CR850. Go to

www.campbellsci.com/downloads to upgrade the datalogger OS.

The resolution of accuracy for the clock set is 10 microseconds if the datalogger

has a hardware revision number greater than 007 (RevBoard field in the

datalogger's Status table). Otherwise, resolution is 10 milliseconds. The clock set

relies on information from the GPRMC sentence. If this sentence is not returned,

a clock set will not occur.

By default, the instruction expects the GPS unit to be set up at 38400 baud,

outputting the GPRMC and GPGGA sentences once per second. The datalogger

expects the start of the second to coincide with the rising edge of the PPS signal.

If there is no PPS signal or if the required sentences come out at less than once per

second, the datalogger will not update its clock.

GPS units with lower baud rates can be used with the GPS() instruction but the

baud rate has to be set for the relevant Com port it is to be connected to either in

the datalogger settings or by including a SetStatus() command after the

BeginProg() instruction in the program (e.g.,

SetStatus("BaudrateCOM4",19200)).

Baud rates of 2400 bps or lower will not work as the GPS unit will not transmit

the two GPS sentences once per second reliably. Similar problems can be

encountered even at higher baud rates if too many optional GPS strings are

selected to be output.

The GPS() instruction has the following syntax:

GPS(GPSArray,ComPort,TimeOffset,MaxTimeDiff,NMEAStrings)

NOTE

User Manual

Description of the parameters follows:

GPSArray The GPSArray parameter is the variable in which to store the

information returned by the GPS. Fifteen values are returned. If

this array is not dimensioned to 15, values will be stored to fill the

array and no error will be returned. If no values are available,

NAN will be returned. The following values are returned by the

GPS:

Array(1) = Latitude, degrees

Array(2) = Latitude, minutes

Array(3) = Longitude, degrees

Array(4) = Longitude, minutes

Array(5) = Speed over ground, knots

Array(6) = Course over ground, degrees

Array(7) = Magnetic variation (positive = East, negative =

West)

Array(8) = Fix Quality (0 = invalid, 1 = GPS, 2 = differential

GPS, 6 = estimated)

Array(9) = Number of Satellites

Array(10) = Altitude, metres

Array(11) = Pulse per second (PPS) length, microseconds

Array(12) = Seconds since last GPRMC sentence

Array(13) = GPS Ready, 10 = ready

Array(14) = Maximum clock change, milliseconds (10 msec

resolution)

Array(15) = Clock change count

ComPort The ComPort parameter is the control port pair to which the GPS

device is attached. Valid options are COM1 (C1/C2), COM2

(C3/C4), COM3 (C5/C6), and COM4 (C7/C8). Rx is used to read

in the NMEA sentences and Tx is used to monitor the PPS from

the GPS. This instruction defaults to a baud rate of 38,400 bps. If

a different baud rate is required, use the SetStatus() instruction to

override the default.

TimeOffset The TimeOffset parameter is the local time offset, in seconds,

from UTC.

MaxTimeDiff The MaxTimeDiff parameter is the maximum difference in time

between the datalogger clock and the GPS clock that will be

tolerated before the clock is changed. If a negative value is

entered, the clock will not be changed.

For dataloggers prior to hardware revision 08, the MaxTimeDiff

parameter should not be set to 0. A minimum value of 20 ms is

recommended. With this hardware, when a GPS() instruction is

in the program the clock is checked each second (regardless of

how often the GPS() instruction is run). The clock is set if any

difference is found. This can result in the clock being set each

second, resulting in skipped records in the data table(s). This

restriction does not apply to hardware revisions 08 or greater.

GPS16X-HVS GPS Receiver

NMEAStrings The NMEAStrings parameter is the string array that holds the

NMEA sentences. If it exists, the GPRMC sentence will reside in

NMEAStrings(1), and the GPGGA sentence will reside in

NMEAStrings(2). Any other sentences will reside in subsequent

indexes into the array (on a first-in basis). Once an index in the

array is used to store a particular sentence, that sentence will

always be stored in that location when updates to the sentence are

received.

5.2 Example Program Using GPS() Instruction

The following wiring and short program provide an example of using the GPS()

instruction with the Garmin GPS16X-HVS.

'Program the GPS16-HVS to use 38.4 kbaud, no parity, 8 data bits, and 1 stop bit

PipeLineMode

Const LOCAL_TIME_OFFSET = -6 'Local time offset relative to UTC time

Dim nmea_sentence(2) As String * 90

Public gps_data(15)

Alias gps_data(1) = latitude_a 'Degrees latitude (+ = North; - = South)

Alias gps_data(2) = latitude_b 'Minutes latitude

Alias gps_data(3) = longitude_a 'Degrees longitude (+ = East; - = West)

Alias gps_data(4) = longitude_b 'Minutes longitude

Alias gps_data(5) = speed 'Speed

Alias gps_data(6) = course 'Course over ground

Alias gps_data(7) = magnetic_variation 'Magnetic variation from true north (+ =

'East; - = West)

Alias gps_data(8) = fix_quality 'GPS fix quality: 0 = invalid, 1 = GPS, 2 =

'differential GPS, 6 = estimated

Alias gps_data(9) = nmbr_satellites 'Number of satellites used for fix

Alias gps_data(10) = altitude 'Antenna altitude

Alias gps_data(11) = pps 'usec into sec of system clock when PPS

'rising edge occurs, typically 990,000 once

'synced

Alias gps_data(12) = dt_since_gprmc 'Time since last GPRMC string, normally less

'than 1 second

Alias gps_data(13) = gps_ready 'Counts from 0 to 10, 10 = ready

Alias gps_data(14) = max_clock_change 'Maximum value the clock was changed in msec

Alias gps_data(15) = nmbr_clock_change 'Number of times the clock was changed

'Define Units to be used in data file header

Units latitude_a = degrees

Units latitude_b = minutes

Units longitude_a = degrees

Units longitude_b = minutes

Units speed = knots

Units course = degrees

Units magnetic_variation = unitless

Units fix_quality = unitless

Units nmbr_satellites = unitless

Units altitude = m

Units pps = ms

Units dt_since_gprmc = s

Units gps_ready = unitless

Units max_clock_change = ms

Units nmbr_clock_change = samples

BeginProg

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