Garmin GPS 16-HVS User manual

Garmin 16-HVS GPS Receiver
Revision: 2/08
Copyright © 2003-2008
Campbell Scientific, Inc.

Warranty and Assistance
The GARMIN 16-HVS GPS RECEIVER is warranted by CAMPBELL
SCIENTIFIC, INC. to be free from defects in materials and workmanship
under normal use and service for twelve (12) months from date of shipment
unless specified otherwise. Batteries have no warranty. CAMPBELL
SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or
replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products.
The customer shall assume all costs of removing, reinstalling, and shipping
defective products to CAMPBELL SCIENTIFIC, INC. CAMPBELL
SCIENTIFIC, INC. will return such products by surface carrier prepaid. This
warranty shall not apply to any CAMPBELL SCIENTIFIC, INC. products
which have been subjected to modification, misuse, neglect, accidents of
nature, or shipping damage. This warranty is in lieu of all other warranties,
expressed or implied, including warranties of merchantability or fitness for a
particular purpose. CAMPBELL SCIENTIFIC, INC. is not liable for special,
indirect, incidental, or consequential damages.
Products may not be returned without prior authorization. The following
contact information is for US and International customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle
repairs for customers within their territories. Please visit
www.campbellsci.com to determine which Campbell Scientific company
serves your country. To obtain a Returned Materials Authorization (RMA),
contact CAMPBELL SCIENTIFIC, INC., phone [phone]. After an
applications engineer determines the nature of the problem, an RMA number
will be issued. Please write this number clearly on the outside of the shipping
container. CAMPBELL SCIENTIFIC's shipping address is:
CAMPBELL SCIENTIFIC, INC.
RMA#_____
815 West 1800 North
Logan, Utah 84321-1784
CAMPBELL SCIENTIFIC, INC. does not accept collect calls.

Garmin 16-HVS GPS Receiver
Table of Contents
PDF viewers note: These page numbers refer to the printed version of this document. Use
the Adobe Acrobat® bookmarks tab for links to specific sections.
1. Overview.......................................................................1
2. Wiring............................................................................ 1
3. GPS Data ......................................................................4
4. CRBasic Programming................................................ 5
4.1 Read GPS Data .........................................................................................5
4.1.1 SerialOpen.........................................................................................5
4.1.2 SerialIn ..............................................................................................5
4.1.3 SerialFlush.........................................................................................5
4.1.4 SerialClose ........................................................................................6
4.2 Parsing and Data Storage Options ............................................................6
4.2.1 SplitStr...............................................................................................6
4.2.2 Converting Strings to Floating Point Numbers .................................6
5. Troubleshooting ..........................................................8
5.1 GPS Setup and Function...........................................................................8
A. CR23X/CR10X Programs ........................................ A-1
A.1 Programming ...................................................................................... A-1
A.1.1 Program Execution Interval......................................................... A-1
A.1.2 Reading GPS Data....................................................................... A-1
A.1.3 Filters........................................................................................... A-3
A.1.4 Managing the Data ...................................................................... A-3
A.1.5 Program Discussion..................................................................... A-4
A.1.6 Troubleshooting .......................................................................... A-8
B. CR9000(X) Program Example................................. B-1
C. Specifications.......................................................... C-1
C.1 Replacement Parts................................................................................C-1
C.2 Specifications.......................................................................................C-1
D. Garmin 16-HVS Setups ........................................... D-1
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Garmin 16-HVS GPS Receiver Table of Contents
ii
Figures
1. Garmin 16-HVS GPS Receiver, Part Number 17215 ................................ 1
2. RJ45 with Flying Leads, Part Number 17217............................................ 2
3. CR1000 to GPS16-HVS Using the 17217 Adapter ................................... 2
4. RJ45 to DB9 Serial Adapter, Part Number 17218 ..................................... 3
Tables
2-1. Wiring the RJ45 Connector with Flying Leads ...................................... 2
2-2. Wiring without the RJ45 Connector (Garmin Wiring)........................... 3
2-3. RJ45 to DB9 RS-232 Adapter ................................................................ 3
3-1. NEMA $GPGGA String Definition........................................................ 4
A-1. P15 for NEMA $GPGGA Data String............................................... A-1
A-2. Filter................................................................................................... A-3
D-1. PGRMC Setup Sentence.................................................................... D-2
D-2. PGRMO Output Sentence Enable/Disable ........................................ D-2
D-3. Supported NMEA 0183 Sentences Order and Size ........................... D-3
D-4. $DGPGGA Global Positioning System Fix Data .............................. D-3

Garmin 16-HVS GPS Receiver
FIGURE 1. Garmin 16-HVS GPS Receiver, Part Number 17215
1. Overview
The Garmin16-HVS is a complete GPS receiver manufactured by Garmin
International, Inc. The Garmin16-HVS has been configured by Campbell
Scientific, Inc. (CSI) to work with CSI dataloggers.
The CR1000, CR3000, CR800, and CR850 dataloggers use serial input
instructions and string handling functions to read, parse and store GPS data.
The CR10X, CR23X, and other dataloggers that support P15 or the SDM-SIO4
four channel serial interface can be used with the Garmin16-HVS. The CR510
and CR200-series do not support serial data input. See Appendix A for
information regarding the CR10X, CR23X, CR5000, CR9000(X) and SDM-
SIO4 applications.
The Garmin16-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 Garmin16-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 Garmin16-HVS do not support differential GPS
correction. The cable can be modified by the user if differential correction is
required.
2. Wiring
Wiring for the Garmin16-HVS can be done with or without the RJ45
connector. When shipped from Campbell Scientific, the Garmin16-HVS has
an RJ45 connector attached to the cable end. The Garmin16-HVS can be
purchased with an RJ45 adapter with flying leads, an RJ45 to DB9 RS-232
adapter, and a magnetic mount. Table 2-1 is the wiring description for the
RJ45 adapter with flying leads. To use Table 2-2, the RJ45 connector must be
cut off the cable.
1

Garmin 16-HVS GPS Receiver
If the Garmin16-HVS is to be connected to a computer for setups, an RJ45 to
DB9 adapter is needed.
TABLE 2-1. Wiring the RJ45 Connector with Flying Leads
GPS-Garmin16-HVS Datalogger Connection Function
Blue 12 volts Power
Orange Ground Power Ground
Black Ground Remote on/off
Green Data in RS232 TX out of GPS
Yellow None 1 Pulse Per Second
FIGURE 2. RJ45 with Flying Leads, Part Number 17217
FIGURE 3. CR1000 to GPS16-HVS Using the 17218 Adapter
2

Garmin 16-HVS GPS Receiver
TABLE 2-2. Wiring without the RJ45 Connector
(Garmin Wiring)
GPS-Garmin16-HVS
Pin Color Function
1 Red Power in, 6.0 to 40 volts DC
2 Black Power ground
3 Yellow Remote power on/off switch, ground for on, float
for off
4 Blue Port 1 Data in, RS232 or TTL levels OK
5 White Port 1 Data out, RS232 Levels
6 Gray PPS
7 Green Port 2 Data in, RS232 or TTL levels, DGPS input
8 Violet Port 2, Data out, RS232, reserved for future use
TABLE 2-3. RJ45 to DB9 RS-232 Adapter
Pin Color Function
NA Red Power in, 12 volts
NA Black Ground
NA Yellow PPS
5 NA GPS, power and remote on/off ground
3 NA GPS data in
2 NA GPS data out
FIGURE 4. RJ45 to DB9 Serial Adapter, Part Number 17218
3

Garmin 16-HVS GPS Receiver
3. GPS Data
The Garmin16-HVS has several data formats available. The Garmin16-HVS is
configured to output the NEMA $GPGGA time and position string. It is
possible to configure the Garmin16-HVS to output other NEMA strings
including the $GPVTG track made good and ground speed string. See
Appendix D for details.
Sample NEMA $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 3-1. NEMA $GPGGA String Definition
Field Description
0 $GPGGA NEMA string identifier
1 hhmmss UTC of Position: Hours, minutes, seconds
2 1111.111 Latitude: Degrees, minutes, thousandths of minutes
3 a N (North) or S (South)
4 nnnnn.nnn Longitude: Degrees, minutes, thousandths of minutes
5 b E (East) or W (West)
6 t GPS Quality Indicator: 0 = No GPS, 1 = GPS, 2 =
DGPS
7 uu Number of Satellites in Use
8 v.v Horizontal Dilution of Precision (HDOP)
9 w.w Antenna Altitude in Meters
10 M M = Meters
11 x.x Geoidal Separation in Meters
12 M M = Meters. Geoidal separation is the difference
between the WGS-84 earth ellipsoid and mean-sea-
level.
13 y.y Age of Differential GPS Data. Time in seconds since
the last Type 1 or 9 Update
14 zzzz Differential Reference Station ID (0000 to 1023)
15 * Asterisk, generally used as the termination character
16 hh Checksum
17 <CR><LF> Carriage return, line feed characters.
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
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Garmin 16-HVS GPS Receiver
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
If the almanac and ephemeris data are not stored in the non-volatile data, GPS
acquisition time is less than 5 minutes. If only the ephemeris data are
unknown, acquisition time is less than 45 seconds. If all data are known
(warm start), GPS acquisition time is less than 15 seconds.
4. CRBasic Programming
CRBasic is used to write programs for the CR1000, CR3000, CR800, and
CR850 dataloggers. These dataloggers use several instructions to read GPS
output, which is asynchronous serial data. As shipped from Campbell
Scientific, the GPS receiver will output data once a second, 1200 baud, 8 data
bits, no parity, and 1 stop bit. Only the GPGGA string is output. See Section
3 for details on the GPGGA string. See Appendix D for specifics on changing
the GPS receiver setups, including using higher baud rates, which the CR1000,
CR3000, CR800, and CR850 support.
4.1 Read GPS Data
4.1.1 SerialOpen
SerialOpen is used to open the appropriate serial port, specify the baud rate,
data format, etc. Any of the six serial ports may be used, but option codes 3, 4
and 5 are not used in this application. Data format is zero, TX delay is zero,
buffer size should be about 2000, which is large enough to prevent the
GPGGA string from overrunning the buffer before data is read by the SerialIn
instruction. If memory is limited, the buffer size can be smaller.
Example: SerialOpen (com1,1200,0,0,2000)
4.1.2 SerialIn
The SerialIn instruction removes data from the buffer declared in the
SerialOpen instruction and places the data in a variable of type string. Use a
timeout of 20, a termination character of 13, and maximum number of
characters of 100, or 1 less than the size of the destination variable. Declare a
string variable of size 101 before using SerialIn.
Example: Public GPSdata as string * 101
Example: SerialIn (GPSData,com1,20,13,100)
4.1.3 SerialFlush
The SerialFlush instruction is used to clear all data from the buffer associated
with the serial port.
5

Garmin 16-HVS GPS Receiver
4.1.4 SerialClose
The SerialClose instruction is used to close the serial port. Once closed, the
SerialOpen command must be used before more data can be read.
4.2 Parsing and Data Storage Options
The CR1000, CR3000, CR800, and CR850 can store data as a string or as a
number. Every time the datalogger stores a string, the size of the string
determines the number of bytes used. If the string was declared to be 101
bytes long, every time the string is written to memory, 101 bytes are used.
Depending on the application, the entire GPGGA string can be stored to
memory or just specific parts. When storing specific parts, some numbers can
be converted to floating data points.
To parse the GPGGA string, first read the entire string into 1 large string (see
Section 4.1). Next parse the string into a group of smaller strings (see Section
4.2.1). Determine which of the smaller strings to keep and which to convert to
floating point number, then store the data.
4.2.1 SplitStr
Use the SplitStr instruction to parse the GPGGA string into an array of strings.
Declare an array of 18 strings of 15 characters.
Example: ParseStr(18) as string * 15
The SplitStr instruction uses the result string, search string, filter string,
number of splits and split option to parse the search string and store the results
in the result string. The GPGGA string uses the comma character (chr(44))
between each parameter. The comma makes a nice marker to parse on.
Example: SplitStr (ParseStr(1),GPSData ,chr(44),18,5)
4.2.2 Converting Strings to Floating Point Numbers
Strings can be converted to floats with the simple assignment operator, but
Latitude and Longitude require more precision than the CR1000, CR3000,
CR800, or CR850 will store as a floating point number.
' Sample CR1000 program to read GPS NMEA GPGGA string
Public location, bytes
public GPSData as string * 101 ' $GPGGA string about 57 characters
PUBLIC ParseStr(18) as string * 15
' Aliases allow proper labels in output data tables,
' and when viewing public variables
alias ParseStr(1) = GPGGA
alias ParseStr(2) = TIME
alias ParseStr(3) = LAT
alias ParseStr(4) = HEMINS
alias ParseStr(5) = LONGI
alias ParseStr(6) = HEMIEW
alias ParseStr(7) = QUAL
alias ParseStr(8) = NUMSATS
alias ParseStr(9) = HDP
alias ParseStr(10) = ALTDE
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Garmin 16-HVS GPS Receiver
alias ParseStr(11) = ALTUNIT
alias ParseStr(12) = GIODAL
alias ParseStr(13) = GEOUNIT
alias ParseStr(14) = AGE
alias ParseStr(15) = DIFFREF
alias ParseStr(16) = ASTERISK
alias ParseStr(17) = CHCKSUM
alias ParseStr(18) = CRLF
' Store the ParseStrd elements of the $GPGGA string as
' short strings.
DataTable(Parsed,1,-1)
Datainterval (0,1,sec,10)
Sample(1,GPGGA,STRING)
Sample(1,TIME,STRING)
Sample(1,LAT,STRING)
Sample(1,HEMINS,STRING)
Sample(1,LONGI,STRING)
Sample(1,HEMIEW,STRING)
Sample(1,QUAL,STRING)
Sample(1,NUMSATS,STRING)
Sample(1,HDP,STRING)
Sample(1,ALTDE,STRING)
Sample(1,ALTUNIT,STRING)
Sample(1,GIODAL,STRING)
Sample(1,GEOUNIT,STRING)
Sample(1,AGE,STRING)
Sample(1,DIFFREF,STRING)
Sample(1,ASTERISK,STRING)
Sample(1,CHCKSUM,STRING)
Sample(1,CRLF,STRING)
endtable
' Store GPS $GPGGA string as a complete string
DataTable (GGA,1,-1)
DataInterval (0,1,Sec,10)
Sample (1, GPSData, string)
EndTable
'Main Program
BeginProg
SerialOpen (com1,1200,0,0,2000)
Scan (1,Sec,0,0)
bytes = SerialInChk (com1)
SerialIn (GPSData,com1,20,13,100)
splitstr (ParseStr(1),GPSData,chr(44),18,5)
Serialflush (com1)
CallTable GGA
CallTable Parsed
NextScan
SerialClose (com1)
EndProg
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Garmin 16-HVS GPS Receiver
8
5. Troubleshooting
Testing and evaluation of serial communications is best done by reducing the
whole system to small manageable systems. Usually some portions of the
whole system are working. The first steps involve finding what is working.
During this process you may find parts of the system that are not working or
mistakes that can be easily corrected. Fix each subsystem before testing
others.
5.1 GPS Setup and Function
Test the Garmin16-HVS for proper operation including the baud rate and
output string. Use a computer, terminal emulator software, a serial port
(RS232), and a 9-pin to 9-pin serial cable. The computer and serial port can be
the same as used to communicate with the datalogger. Terminal emulation
software is pretty common. Hyperterm is supplied as part of Windows ™ and
works. Procomm ™ is another communication software package that works
well.
Set up the software for the correct serial port, 1200 baud, 8 data bits, 1 stop bit
and no parity. Flow control should be off. Using the serial cable, connect the
Garmin16-HVS to the computer serial port. Power up the Garmin16-HVS.
The GPS antenna should have a clear view of the sky. Don’t expect the GPS
antenna to work indoors. The $GPGGA string should be displayed once a
second. Make sure the $GPGGA string is showing a valid GPS fix. A valid
GPS fix will display time, position and have a GPS quality number greater
than zero. Part number 17218, RJ45 to DB9 adapter, is needed to connect the
Garmin16-HVS to the computer serial cable.

Appendix A. CR23X/CR10X Programs
A.1 Programming
Program instruction 15 (P15) is used to read the NEMA $GPGGA string of
time and position data. Each iteration of P15 can either read the numeric fields
or read everything. When reading the numeric fields, such as time, latitude,
longitude and elevation, P15 requires non-numeric delimiters between data
points. The only available format of GPS data with delimiters is the NMEA
0183 format. Program instruction 15 (P15) reads serial data and discards non-
numeric values. All non-numeric values act as delimiters between numbers,
and decimal points can also act as delimiters. P15 can be used to import
everything in the string, character by character, and convert it to the decimal
equivalent. The decimal equivalent method is seldom used, and only when the
general area (hemisphere) is not known.
A.1.1 Program Execution Interval
When the PPS signal is used to trigger the read data function (P15), the
program table execution interval does not matter. Otherwise the timing
between the Garmin16-HVS output and the datalogger read must be
considered. Generally the execution interval can not be less than 2 seconds
when the PPS signal is not used.
A.1.2 Reading GPS Data
Table A-1 is a sample CR23X P15 instruction for reading NMEA $GPGGA
data string. The second parameter has two dashes indicating data buffering has
been turned off. The CR10X does not have the data buffering option.
TABLE A-1. P15 for NEMA $GPGGA Data String
Parameter Data Description
1 1 Repetitions
2 61 -- Configuration code for RS232 ASCII data at 1200 baud
with data buffering turned off. The -- indicates data
buffering turned off. Decimal delimiter
3 1 Delay before sending data out
4 05 Control ports. Two digit format AB. A is for
handshaking and set to zero. B in this example is control
port 5 (datalogger RCV). Garmin16-HVS
communication cable: GPS transmit to control port 5 in
this example
5 1 Input location where first character to transmit is stored.
Note: nothing is actually transmitted
6 0 Number of consecutive input locations to send
7 42 Termination character, 42 is ASCII equivalent of the
asterisk
8 100 Maximum number of characters to receive.
9 80 Delay in mS. How long to wait for $GPGGA string
10 1 Starting input location for time and position data
11 1 Multiplier, always 1.
12 0 Offset, always 0.
A-1

Appendix A. CR23X/CR10X Programs
P15 parameters 4, 5, and 10 are somewhat variable. When using a CR23X,
parameter 4 can be set to 05, 06 or 07 depending on what control ports are
used. A CR10X can use control ports 1 through 6. Wiring of the
communication cable depends on the selection for parameter 4. With a CR23X
the GPS transmit wire is connected to the control port selected in parameter 4.
With a CR10X, the GPS transmit wire is connected to the control port 1 higher
then the control port listed in parameter 4.
P15 is executed when the PPS signal drives control port 8 high. P15 will wait
until one of three conditions is met: the time-out listed in parameter 9 has
expired, the maximum number of characters in parameter 8 have been read, or
the termination character listed in parameter 7 has been read.
P15 parameter 10 is the first input location you wish to store GPS data in.
Fifteen sequential input locations will be used to store time and position.
Example A-1. Program Instruction 15 (P15) for CR23X
Port Serial I/O (P15)
1: 1 Reps
2: 61 -- ASCII/RS-232, 1200 Baud, decimal delimiter
3: 1 Delay (units = 0.01 sec)
4: 5 Control Ports
5: 1 Output Loc [ Bulk ]
6: 0 No. of Locs to Send
7: 42 Termination Character
8: 100 Maximum Characters
9: 80 Time Out Delay (units = 0.01 sec)
10: 1 Loc [ Raw_time1 ]
11: 1 Mult
12: 0 Offset
Example A-2. Program Instruction 15 (P15) for CR10X
8: Port Serial I/O (P15)
1: 1 Reps
2: 61 ASCII/RS-232, 1200 Baud, decimal delimiter
3: 1 Delay (units = 0.01 sec)
4: 1 First Control Port
5: 1 Output Loc [ Bulk ]
6: 0 No. of Locs to Send
7: 42 Termination Character
8: 100 Maximum Characters
9: 80 Time Out Delay (units = 0.01 sec)
10: 1 Loc [ Raw_time1 ]
11: 1.0 Mult
12: 0.0 Offset
Communication cable wiring for:
NOTE
CR23X/Example A-1 — PPS to C8, GPS transmit to C5.
CR10X/Example A-2 — PPS to C8, GPS transmit to C2.
A-2

Appendix A. CR23X/CR10X Programs
A.1.3 Filters
Filters can be used to make sure P15 reads the correct data string. Filters also
ensure P15 starts to read the string at the beginning of the string. To use a
filter, follow P15 with instruction P63 (extended parameters). P63 is used to
define the filter. Enter the desired filter in P63.
TABLE A-2. Filter
ASCII Equivalent Character
36 $
71 G
80 P
71 G
71 G
65 A
A.1.4 Managing the Data
Several of the data values in the $GPGGA string are too large to view or write
to final storage. Some simple math is used to parse the data.
The UTC time is in the format hhmmss where hh is the hours, mm is the
minutes and ss is the seconds. Six digits are too many to view with the
datalogger display and some software. Add 0.3 to the raw time field. Multiply
the raw time input location by 0.01 to reduce the magnitude and place the
seconds in the fractional portion of the number. Next use P45 to write the
integer portion (hours/minutes) to a new input location, then use P44 to write
the fractional portion to another input location (seconds) and multiply that
location by 100. The last step is to use P45 again to take the integer portion of
the input location for seconds. The result is hour/minutes in one input location
and seconds in another.
The latitude and longitude can be parsed with the P15 instruction when decimal
delimiter is on. If P15, parameter 2 is 6x, where the x selects the baud rate,
every non-numeric value and decimal point will act as a delimiter. The
Degrees and Minutes will be placed in one input location, and the minute
fractional portion will be placed in the next input location. The decimal
delimiter preserves the resolution of the original measurement.
Further parsing of the latitude and longitude may be necessary. Longitude
degrees and minutes can range in value up to 18059, which exceeds the low
resolution format of the dataloggers final storage area. Either parse the latitude
and longitude degrees and minutes the same way the time was parsed, or store
the data in high-resolution format.
The GPS quality number can be used to determine if you have a valid GPS fix
and if the datalogger received the data properly. Use P89 to test if the GPS
quality number is greater than or equal to one. There is a catch to using the
GPS quality number to verify your data. P15 will write to fifteen input
locations if everything works correctly. If P15 fails to read the GPS data, only
the first input location is written to. The GPS quality number will be
unchanged. If P15 fails to read the GPS data, the value displayed in the first
input location will be 99999. The datalogger actually stores FFFFFFFFh, a
very large number. The time field includes six digits, which can be greater
than 99999. This limits the usefulness of the time field as a test for a valid
A-3

Appendix A. CR23X/CR10X Programs
GPS fix. A better approach is to overwrite the GPS quality location with zero
before executing P15. Use P30 to overwrite one input location.
If the GPS time is used to set the datalogger clock, the GPS time must be
parsed into three input locations: Hour, Minutes, Seconds. P114 is used to set
the datalogger clock to match values in input locations. Some time will have
passed between the GPS fix and when the program table reaches the P114
instruction. Adjustments can be made by adding a second or two. Be careful
about setting seconds to a number greater than 59. You can also correct the
UTC time to local time. Table based dataloggers require year, day, hour,
minute, and seconds to use P114. Only hour, minutes, and seconds are
available from the $GPGGA string. The PGRFM string includes the month,
day and year, but is difficult to use.
A.1.5 Program Discussion
Wiring when using RJ45 adapter:
Function Color Datalogger Connection
Power in Blue 12 volts
Power ground Orange Ground
Power switch Black ground
TXD Green C5
PPS Yellow C8
The Garmin16-HVS should be setup for 1200 baud, 8 data bits, 1 stop bit and
no parity. The GPGGA string should be output. The 1 pulse per second signal
should be output with a pulse duration of 80 milliseconds.
The code required to read the GPS information and store it to final storage is in
Subroutine 98. Subroutine 98 is interrupt driven and triggered when a rising
edge is detected on Control port 8. The Garmin16-HVS has a 1 PPS signal
which is wired to control port 8. The transmit data line of serial port 1 on the
Garmin16-HVS is wired to control port 5. The Garmin16-HVS serial port 2
generally is not used.
When the 1 PPS signal triggers subroutine 98, P15 is executed. P15 is setup to
read ASCII serial data. Each data point is separated by a non-numeric
character or a decimal point. Fifteen input locations are used as temporary
storage for the $GPGGA string. Table 3.1 explains the $GPGGA string.
The input locations used for the $GPGGA string are:
1) Raw_Time, Time in hours, minutes, and seconds
2) LatDegMin, Latitude degrees and minutes
3) Lat_Frac, Latitude fractions of minute
4) LngDegMin, Longitude degrees and minutes
5) Lng_Frac, Longitude fractions of minute
6) Quality, GPS quality indicator
7) NumSats, Number of satellites in use
8) HDPWhole, Horizontal Dilution of Precision
9) HDPFrac, Horizontal Dilution of Precision, tenths
10) Elevation, Elevation in meters
11) Geoidal, Geoidal separation in meters
12) Geoidalth, Geoidal separation in meters, tenths
13) Age, Age of differential GPS data
14) Agetenth, Age of differential GPS data, tenths
15) DiffID, Differential reference station ID
A-4

Appendix A. CR23X/CR10X Programs
Additional input locations used in the example program are:
18) Orig_TM, Copy of original time
19) Int1, Place holder for math
20) Hours, formatted hours
21) Minutes, formatted minutes
22) Seconds, formatted seconds
23) remainder, place holder for math
Before writing any datalogger code, it’s best to enter all the input locations
needed. In Edlog, open the input location editor (F5) and enter names for the
input locations listed above. When an input location is needed, use the input
location pick list (F6).
;{CR23X}
;
*Table 1 Program
01: 60 Execution Interval (seconds)
; Instruction to eliminate warning about unused subroutine, not needed
1: If Flag/Port (P91)
1: 11 Do if Flag 1 is High
2: 98 Call Subroutine 98
*Table 2 Program
02: 0.0000 Execution Interval (seconds)
*Table 3 Subroutines
1: Beginning of Subroutine (P85)
1: 98 Subroutine 98
;--- read serial data non-buffered
2: Port Serial I/O (P15)
1: 1 Reps
2: 61 -- RS-232 ASCII (decimal delimiter), 1200 Baud
3: 1 Delay (0.01 sec units) before TX
4: 5 No RTS/DTR, C5 TXD/RXD
5: 1 Start Loc for TX [ Raw_Time ]
6: 0 Number of Locs to TX
7: 42 Termination Character for RX
8: 100 RX Buffer Size or Max Chars to RX if Par 2 indexed (--)
9: 80 Time Out for CTS (TX) and/or RX (0.01 sec units)
10: 1 Start Loc for RX [ Raw_Time ]
11: 1.0 Mult for RX
12: 0.0 Offset for RX
;--- filter for $GPGGA
3: Extended Parameters (P63)
1: 36 Option ;$
2: 71 Option ;G
3: 80 Option ;P
4: 71 Option ;G
5: 71 Option ;G
6: 65 Option ;A
7: 0 Option
8: 0 Option
A-5

Appendix A. CR23X/CR10X Programs
; Test for valid GPS fix and string read
4: If (X<=>F) (P89)
1: 6 X Loc [ Quality ]
2: 3 >=
3: 1 F
4: 30 Then Do
; Make a copy of time
5: Z=X (P31)
1: 1 X Loc [ Raw_Time ]
2: 18 Z Loc [ Orig_TM ]
; Add 0.45 to time stamp to eliminate complications with
; floating point math, P44, and P45
6: Z=X+F (P34)
1: 18 X Loc [ Orig_TM ]
2: 0.45 F
3: 18 Z Loc [ Orig_TM ]
; Move minutes and seconds right of decimal
7: Z=X*F (P37)
1: 18 X Loc [ Orig_TM ]
2: .0001 F
3: 19 Z Loc [ Int1 ]
; Pluck off hours
8: Z=INT(X) (P45)
1: 19 X Loc [ Int1 ]
2: 20 Z Loc [ Hours ]
; Subtract hours out
9: Z=X-Y (P35)
1: 19 X Loc [ Int1 ]
2: 20 Y Loc [ Hours ]
3: 19 Z Loc [ Int1 ]
; Move decimal left 2 places
10: Z=X*F (P37)
1: 19 X Loc [ Int1 ]
2: 100 F
3: 19 Z Loc [ Int1 ]
; Pluck off minutes
11: Z=INT(X) (P45)
1: 19 X Loc [ Int1 ]
2: 21 Z Loc [ Minutes ]
; Subtract out minutes
12: Z=X-Y (P35)
1: 19 X Loc [ Int1 ]
2: 21 Y Loc [ Minutes ]
3: 19 Z Loc [ Int1 ]
A-6

Appendix A. CR23X/CR10X Programs
; Move decimal left 2 places
13: Z=X*F (P37)
1: 19 X Loc [ Int1 ]
2: 100 F
3: 19 Z Loc [ Int1 ]
; Pluck of seconds
14: Z=INT(X) (P45)
1: 19 X Loc [ Int1 ]
2: 22 Z Loc [ Seconds ]
; Write data to final storage every time there is
; a valid read of GPS data
15: Do (P86)
1: 10 Set Output Flag High (Flag 0)
16: Set Active Storage Area (P80)^18796
1: 1 Final Storage Area 1
2: 101 Array ID
; Write datalogger based time stamp
17: Real Time (P77) ^27570
1: 0011 Hour/Minute,Seconds (midnight = 0000)
; Write GPS based time stamp
18: Sample (P70) ^6080
1: 3 Reps
2: 20 Loc [ Hours ]
; Set resolution to high for latitude and Longitude
19: Resolution (P78)
1: 1 High Resolution
20: Sample (P70) ^20303
1: 4 Reps
2: 2 Loc [ LatDegMin ]
; Write elevation in meters
21: Sample (P70) ^32246
1: 1 Reps
2: 10 Loc [ Elevation ]
; Set resolution low
22: Resolution (P78)
1: 0 Low Resolution
; Write the number of satellites in view
23: Sample (P70) ^1910
1: 1 Reps
2: 7 Loc [ NumSats ]
; Reset the the GPS quality number
24: Z=F x 10^n (P30)
1: -1 F
2: 00 n, Exponent of 10
3: 6 Z Loc [ Quality ]
A-7

Appendix A. CR23X/CR10X Programs
A-8
25: End (P95)
26: End (P95)
End Program
This is a blank page.
A.1.6 Troubleshooting
The first step is to verify that it really does not work. With the Garmin16-HVS
running and the datalogger program running, look at the input location for GPS
Quality Number. This location will show a one when the Garmin16-HVS
output is picked up by the datalogger. The input location for parsed time and
position are good locations to check. The location for seconds should update
every time the GPS data is updated.
If the GPS time and position data are not shown in the input locations, check
the communication cable wiring.
If the Garmin16-HVS data is not correct every program table execution but
correct sometimes, check the P15 time-out. It may need a longer time-out.
Also check the P15 maximum number of characters to receive, usually 100 is
enough. Check the P15 termination character; it should be set to 42 (*). The
termination character should also work if set to 13 or 10. Also check the
buffering and filter. Buffering should be turned off. On a CR23X, index
parameter 2. The CR10X does not buffer data.
For P15 to properly read the $GPGGA string, P15 must be executing while the
$GPGGA string starts and finishes. The P15 time-out needs to be long enough
to pick up the string. The string is output once a second. If P15 starts to
execute while the Garmin16-HVS is sending the string, P15 must wait until the
string is sent again plus the amount of time it takes to send the string. It
shouldn’t need more than 1.5 seconds. P15 time-out is in units of 0.01
seconds, 100 = 1 second. A longer time-out will force the datalogger to wait
until the time-out has expired or the termination character is received or the
maximum number of characters are received. If the data in input locations
seem to move from the proper input location to another input location, P15 is
stopping before the entire string has been read. An example is latitude being
displayed in the time field, then in the latitude field. P15 works best when P15
quits reading data because the termination character has been read. Using the
PPS to trigger subroutine 98 is the best way to start P15 just before the
Garmin16-HVS sends the $GPGGA string. If the PPS signal pulls C8 high
while the datalogger is in the middle of executing an instruction, it may not be
able to run subroutine 98 before the $GPGGA string has started, which will
cause the datalogger to miss the data string. Turning on the data buffering
(CR23X only) may remedy the problem. Lengthening the serial time-out to
allow P15 to execute for 2 cycles of NMEA output may help. Otherwise the
SDM-SIO4 may be required or the datalogger program will need to be
simplified.
The datalogger will not pick up valid data until the Garmin16-HVS has a valid
GPS fix, except during a Garmin16-HVS warm start where time can be read
before position is known. Don’t spend a lot of time trouble shooting a
phantom problem just because the GPS receiver does not have a valid GPS fix.