FT Technologies acures FT722 - FL.3: Set or Query the Selective Filter

Section 6 Parameter Settings
71 FT722 & FT742 (RS485) – FF & PM Sensors – User Manual
6.4.14 FL.3: Set or Query the Selective Filter
Command
Parameter
FL (selective filter)
Command
Syntax
SET Sensor:
$<listenerID>,FLS<FilterStatus><period>*<checksum><cr
><lf>
$aa,FLScxxx*hh<cr><lf>
QUERY Sensor:
$<listenerID>,FL?S*<checksum><cr><lf>
$aa,FL?S*hh<cr><lf>
Sensor output:
$<talkerID>,FL=<FilterStatus>,<period>*<checksum><cr>
<lf>
$aa,FL=c,xxx*hh<cr><lf>
Parameters
<FilterStatus>
E
D
Enabled
Disabled
<Period>
000 to 255
Length of validity period (in increments of 0.1 seconds):
000 A single error will trigger the error flag
001 2 consecutive errors will trigger the error flag (0.2 seconds)
Examples
Example 1
Query the Selective Filter Status.
Message
Comment
$01,FL?S*//<cr><lf>
Query the Selective Filter status.
$WI,FL=E,005*hh<cr><lf>
Sensor reports it is enabled with a 5 reading
(0.5 second) filter.
Example 2
Enable or Disable the Selective Filter Status.
$01,FLSE010*//<cr><lf>
Enable the Selective Filter for up to 10
readings (1 second).
$01,FL?S*//<cr><lf>
Query the Selective Filter status.
$WI,FL=E,010*hh<cr><lf>
Sensor reports it is enabled with a 10 reading
(1 second) filter.
$01,FLSD*//<cr><lf>
Disable the Selective Filter.
Description
In addition to the averaging filter described in Section 2.5, the sensor has a feature called the
Selective Filter. The scheme allows the user to set a “validity period”, during which the sensor
will exclude invalid readings from entering the averaging filter. The output will freeze on the
last previous “good” reading and only raise an error flag once the number of bad readings
exceeds the validity period. This scheme can be enabled by factory configuration. The filter
is turned off by default to match legacy behaviour.
Depending on the control system used, this may improve data quality.