Airmar NMEA 2000® Depth, Датчики - Manual (Page 56)

DST200 User Manual revision 1.000
Proprietary and Confidential
54
_ NMEA 2000® RECEIVED PARAMETER GROUP _
PGN
126208
(0x1ED00)
Request Group Function
Single Frame: No Access Level: 0
For further information about the NMEA 2000® protocol, including field descriptions refer to the document, NMEA 2000® Standard for Serial-
Data
Networking of Marine Electronic Devices available from NMEA.
Notes
When this PGN is received by the DST, the unit will compare the specified Request Parameters in fields 6, 7 (and any following fields) against the contents of the actual fields in
the requested PGN. The only fields that may be used as Request Parameters are those which indicate a "Yes" in the "Request Param." column in the detailed description for the
specific transmitted PGN. If all specified parameters match the values in the corresponding fields, then the requested PGN will be transmitted. If any of the parameters do not
match, then the unit will respond by transmitting the Acknowledge Group Function PGN 126208 with the appropriate error code(s) provided.
This PGN may also be used to specify the Transmission Interval (Update Rate) between successive transmissions of a periodically transmitted PGN. (Note: certain PGNs do not
permit changing the transmission interval.) For all single-frame PGNs that permit changing the transmission interval, the allowable range of interval values is 50 ms to 60
seconds. For all fast packet PGNs that permit changing the transmission interval, the allowable range of interval values is 100 ms to 60 seconds. Note that it may be possible to
specify an update rate that is faster than the unit's ability to generate new data. In this case, the PGN will be transmitted only as new data becomes available.
Use the proprietary received PGN 126720-130 to reset all Transmission Intervals for all PGNs to their factory defaults.
Refer to the detailed descriptions of the specific transmitted PGNs in this document for any exceptions or special cases with regard to using the Request Group Function PGN
126208 with each PGN.
All parameter value fields must be padded (with 1's) if necessary to ensure byte boundaries are adhered to.
When the Requested PGN field 2 (of PGN 126208) refers to a proprietary PGN, fields 1 and 3 (manufacturer code and industry group) of the proprietary PGN must be specified
first in the list of field number and parameter value pairs in PGN 126208. All other field number and parameter value pairs may appear in any order in this message.
For proprietary PGNs described in this document, fields 1, 2, and 3 (manufacturer code, reserved bits, and industry group) of the proprietary PGN may optionally be combined
into a single 16-bit field when specifying fields in PGN 126208. For Airmar proprietary PGNs, the 16-bit field is constructed as follows:
• bits 15-13 = binary 100 = decimal 4 (industry group for "Marine Industry")
• bits 12-11 = binary 11 = reserved bits
• bits 10-0 = binary 000 1000 0111 = decimal 135 (manufacturer code for Airmar Technology)
The concatenation of these 16 bits produces the binary value 1001 1000 1000 0111 = hexadecimal 0x9887. Therefore, instead of specifying the two fields, 11-bit field 1 and
3-bit field 3 for a proprietary PGN, it is permissible to specify a single 16 bit field 1, containing the value 0x9887, for the proprietary PGNs described in this document.