17
of
27
Option 32.0 - Trim limit default (0/1) LV3
0 = Default Trim Limit of
5%
1 = Enables options 32.1 to 32.4
Options 32.1 to 32.4 - Trim limits (0.0 – 25.0) LV3
Option 32.0 is only available if option 30.5 (oxygen input function) has been set for closed loop oxygen
trim.
It is possible for the system to trim the air or fuel drives up to a maximum deviation of ±25.0% of the total
air or fuel flow for the chosen trim drives.
If option 32.0 is set to 0, the default trim limit will be ± 5.0% for all profile selections. Option parameters
32.1 to 32.4 will not be available.
If option 32.0 is set to 1, it is possible to individually adjust the trim limit for each profile selection using
option parameters 32.1 to 32.4. The trim limit may be adjusted from 0.0% (no trim) up to a maximum of ±
25.0% (maximum allowable trim).
It is the responsibility of the commissioning engineer to ensure the trim limit set will not allow a
hazardous combustion condition to occur in the event of an oxygen probe failure. Where oxygen
is to be considered safety critical, option parameters 31.X should be used to setup a second
oxygen monitor. When a second oxygen monitoring system is used, the oxygen can be
considered fail-safe, and the trim limits can be set up to 50% instead of 25%.
Options 33.1 to 33.4 - Trim integral gain (Default 10%) LV3
Options 33.1 to 33.4 are only available if option 30.5 (oxygen input function) has been set for closed loop
oxygen trim.
In order for the oxygen trim control loop to be stable, the integral gain must be set correctly. Options 33.1
to 33.4 allow the integral gain to be set individually for each profile combination to any value between 0.0
and 99.9%. As a general recommendation, the integral gain should be initially set to 10.0%. This value
must be set above 0.0 for the system to apply trim.
If the burner is firing, it is only possible to make an adjustment to the option parameter that relates to the
selected profile. If the burner is not firing, the integral gain for any profile selection may be adjusted.
Option 34.0 - Trim proportional gain (0/1) LV3
Options 34.1 to 34.4 - Trim proportional gain (0.0 – 99.9%) LV3
Options 34.0 to 34.4 are only available if option 30.5 (oxygen input function) has been set for closed loop
oxygen trim.
If oxygen trim proportional gain is not required for any profile selection, set option parameter 34.0 to
0
.
If oxygen trim proportional gain is required, set option parameter 34.0 to
1
. Option parameters 34.1 to
34.4 will then become available. Options 34.1 to 34.4 allow the loop gain to be set individually for each
profile selection to any value between 0.0 and 99.9%.
Oxygen trim proportional gain is not normally required.
O 2
O 2
O 2
Summary of Contents for NEXUS NX6100 series
Page 3: ...3 of 27...
Page 4: ...4 of 27...