Airmar NMEA 2000® Depth, Датчики - Manual (Page 4)

DST200 User Manual revision 1.000
Proprietary and Confidential
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Single Frame: Yes = the Parameter Group has been designed to fit within the 8 bytes of
a single CAN frame. No = the Parameter Group is larger than 8 bytes, so must be
transmitted in multiple CAN frames using either NMEA 2000® Fast Packets, or (TBD)
ISO 11783 multi-packets, using the Data Transfer Transport Protocol (PGNs 60160 and
60416).
Priority: NMEA 2000® parameter groups are each assigned a priority value between 0
and 7, which is used to arbitrate between two devices attempting to transmit
simultaneously. 0 is the highest priority, and 7 is the lowest. The Priority field at the top
of each of the detailed specification pages shows three values separated by slashes (e.g.
6/Y/Y). The first value is the default priority, between 0 and 7, of the parameter group as
defined in the NMEA 2000® Standard. The second value is "Y" if the priority for this
parameter group may be changed using the Command Group Function PGN 126208, or
"N" if the priority may not be changed. The third value is "Y" if the priority is saved in
nonvolatile EEPROM memory within the device and maintained upon cycling power, or
"N" if the priority reverts to the default value upon cycling power.
Update Rate: Some NMEA 2000® parameter groups are transmitted periodically by the
DST. The Update Rate field at the top of each of the detailed specification pages shows
three values separated by slashes (e.g. 100 ms/Y/Y). The first value is the default update
rate for the parameter group, as defined in the NMEA 2000® Standard. If the default
behavior for the parameter group is not to transmit periodically, then this first value will
be 0 (zero). The second value is "Y" if the update rate for this parameter group may be
changed using the Transmission Interval field in the Request Group Function PGN
126208, or "N" if the update rate may not be changed. The third value is "Y" if the
update rate is saved in nonvolatile EEPROM memory within the DST and maintained
upon cycling power, or "N" if the update rate reverts to the default value upon cycling
power.
Destination: Global or Address. A Global Destination means that the parameter group
was designed to be broadcast for use by all receiving devices on the bus. If Destination =
Address, this means the parameter group was designed to be transmitted to a specific
device on the bus. In this case, the address of the destination device must be provided
within the PGN.
Query Support: If the parameter group supports queries, then the DST will transmit the
parameter group if requested by another device on the bus. The request must be made
using either the ISO Request PGN 59904, or the Complex Request Group PGN 126208.
Access Level: The DST contains a security mechanism whereby certain PGNs require an
access sequence to be performed in order to enable the functionality in the PGN. If the
indicated Access Level is 0, then the PGN is fully functional without requiring an access
sequence to be performed. If the indicated Access Level is nonzero, then it is necessary
to perform an access sequence using the proprietary transmitted PGN 065287, Access
Level, before the functionality of the PGN will be enabled.