Airmar NMEA 2000® Depth, Датчики - Manual (Page 36)

DST200 User Manual revision 1.000
Proprietary and Confidential
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This PGN is transmitted in response to a PGN 126208 Request Group Function message. Fields 1, 3, and 4 must each be fully specified in the request in order for this PGN to be
transmitted. If field 5 (filter type) is specified in the request, then the PGN will be transmitted once with the data for the specified filter type. If field 5 (filter type) is not specified
in the request, then this PGN will be transmitted multiple times, once for each supported filter type.
This PGN does not respond to ISO Requests (PGN 59904).
This PGN is used to establish the sample interval, type of filter, and filter coefficients used when measuring the Water Temperature value reported in PGNs 130310 and 130311.
The purpose of the filter is to remove unwanted frequency components present in the raw temperature data provided by the thermistor. The filter settings represent a trade-off
between smoothness of readings and responsiveness to changes in the temperature.
This PGN is intended to eventually accommodate different types of filters. At this time only two filter options are supported: Filter Type 0 (No Filter), and Filter Type 1 (Basic
IIR Filter).
To change to a different filter without changing any of the filter parameters or coefficients, use the Command Group Function PGN 126208, specifying the individual fields in
PGN 126720-44 as follows.
PGN 126720
Field Value
1 135 (decimal)
3 4 (decimal)
4 44 (decimal)
5 Desired filter type
The different filter types are described on the following pages.