Garmin Apollo CNX80, Installation Manual

Page: 130 / 168

Appendix B - Serial Interface Specifications
B-14 560-0982-00 Rev D Apollo CNX80 Installation Manual
mk..............Frequency: m = MHz, where m = MHz frequency – 30h, with the desired frequency
ranging from 108 to 111 MHz, or 3Ch to 3Fh; k = (desired kHz offset / 25 kHz) + 30h,
where the desired frequency ranges from 000 to 950 kHz, or the even numbers from 30h to
56h. Note that the field will be checked to ensure that it is in range and a valid localizer
frequency. Frequencies used for VORs, which can also be found in the range of 108.10 to
111.95 MHz, will not be accepted in this message type.
Example message:
$PMRRV2331<Sp><Sp>><<chksm><CR><LF>
Identifier is “31 ”, indicating a runway, and the localizer frequency is 110.300 MHz.
B.2.1.4.6 Distance/Speed/Time Message
If an SL30 is connected to the CNX80, the CNX80 will send the following message to the SL30.
$PMRRV41rrrrssshmm<CHECKSUM><CR><LF>
rrrr is the distance to the station in 0.1nm units
sss is the ground speed in knots
hmm is the time to the station in hours and minutes
This message is used to output the range, ground speed, and ETA decoded from an external RNAV sensor
(DME or GPS).
Message format:
“V” ............Message class. This is a VHF NAV message.
“41” ...........Message identifier.
rrrr .............Range from DME station in 1/10
th
of a nautical mile units. The first two digits are the 10s
and 1s place of the range, and the last digit is the 1/10
th
s place. This field may range in
value from 0.0 NM (“0000”) to 999.9 NM (“9999”). If the distance from the DME
station is greater than 999.9NM, the value should be encoded as “----”.
sss..............Ground speed with respect to DME station in knots. This field may range in value from 0
knots (“000”) to 999 knots (“999”). If the ground speed with respect to the DME station
is greater than 999 knots, the value should be encoded as “---”.
hmm...........Time to station in hours and minutes. This field may range in value from 0 hours and 0
minutes (“000”) to 9 hours and 59 minutes (“959”). If the time to the station is greater
than 9 hours and 59 minutes, the value should be encoded as “---”.
Example message:
$PMRRV410983055147<chksm><CR><LF>
Range from DME station is 98.3 NM, ground speed with respect to station is 55 knots, and the
estimated time to the station is 1 hour and 47 minutes.