V A L A V I O N I C S L T D
N A V 2 0 0 0 N A V I G A T I O N S Y S T E M
I N S T A L L A T I O N A N D O P E R A T O R ’ S M A N U A L
Pre-Release Issue
Page 23 of 29
Sept. 2013
Message format:
$PMRV27E4N<chksm><CR><CR><LF>
This example command would set the active VOR frequency to 117.100 MHz. This can be
interpreted by noting that the ASCII ‘E’ corresponds with 45h, + 30h = 75h, converted to decimal
equals 117 for the MHz portion of the command. The kHz portion converts ASCII ‘4’ to 34h, -
30h = 4h, x 25 kHz steps = 100 kHz. This command would also set the receiver function to
normal, leaving the standby channel inactive.
Note: The NAV 2000 will check input frequencies for validity. An RS-232 serial error message
output will be generated if the frequency is invalid.
SET STANDBY VOR/LOC FREQUENCY AND RECEIVER FUNCTION
This message is used to set the standby VOR or Localizer frequency as well as the receiver
operating function. The NAV 2000 can detect if the supplied frequency corresponds to a VOR or a
Localizer channel, so this command will work for both types of NAV aids.
Message format:
“V”………..Message class. This is a VHF NAV message.
“28”………Message identifier.
mk………..Standby VOR/LOC frequency:
m = desired frequency in MHz in hexadecimal, where m = desired
frequency – 30h, with desired frequency in range of 108 to 117 MHz.
k
= desired frequency in kHz, where k = (desired frequency / 25 kHz) +
30h, desired frequency in range of 000 to 975 kHz in 50 kHz steps, or the
even numbers from 30h to 56h.
a………….Receiver function: N = normal, 0 = unchanged.
Example message:
$PMRRV28?PN<chksm><CR><LF>
This example command would set the standby VOR frequency to 111.800 MHz. This is
interpreted by noting that the ASCII ‘?’ corresponds with 3Fh, + 30h = 7Bh, converted to decimal
equals 111 for the MHz portion. The kHz portion converts ASCII ‘P’ to 50h, -30h, -30h yields
20h, x 25 kHz steps = 800 kHz portion. This command would also set the receiver function to
normal, so the receiver would receive only the active VOR channel.
Note:
The NAV 2000 will check input frequencies for validity. An RS-232 serial message output
will be generated if the frequency is invalid.
SET STANDBY COM FREQUENCY AND TRANSRECEIVER FUNCTION
This message is issued to set the standby COM frequency.
Message format:
“V” ..................... Message class. This is a VHF NAV message.
“29”.................... Message identifier.
Mk...................... Standby COM frequency:
m = desired frequency in MHz in hexadecimal, where m = desired frequency - 30h, with desired
frequency in range of 118 to 136 MHz, or 162 MHz.
k
= desired frequency in kHz, where k = (desired frequency / 25 kHz) + 30h, with desired
frequency in range of 000 to 975 kHz in 25 kHz steps.
