postprocessing

Usage

>> postprocessing [ channels | mode | status | command | dc_alpha | dc_tau | dc_tdelay | dc_ctcoeff ]

Security

None.

Description

The postprocessing feature enables the logger to perform various post-processing operations on data measured and stored by the logger. It operates on data stored in EasyParse format in dataset-1 and writes EasyParse format into dataset-4 based on the channels and parameters requested. The postprocessing can occur as soon as there is an EasyParse dataset available (even if logging is in progress). If the instrument is powered cycle while performing the postprocessing, it will continue the postprocessing after power cycling.

This feature was introduced in firmware version 1.136. Firmwares between 1.102 and 1.135 carry a different implementation of the postprocessing command.

• channels [ = listofchannelsstats] is the list of channels statistics to be obtained. Items in the list are separated by the character | and follow the format <aggregatefunction>(<channel>), where<channel>is a channel label and<aggregatefunction>is either:

  • mean, average value in the bin

  • std, standard deviation of the bin

  • count, number of samples in the bin

  A maximum of 24 channels is supported. The generated dataset-4 channels order will follow the same order as <listofchannelsstats>. 

  
  

• mode [ = continous|regimes ] Select the mode of operation for the postprocessing. 

  • When the mode is regimes, it indicates the postprocessing will use settings from postprocessing_regime and postprocessing_regimes commands to process the data.  Behavior mimics the real-time regime/regimes command.

  • When the mode is continuous, all the data is processed without performing any binning.  This is used for performing dynamic correction while maintaining the same sampling rate

• status is a read-only parameter that returns the current state of the finite state machine for the instrument's post-processing function. Possible statuses are:

  • disabled, indicating that the postprocessing is waiting to be enabled.  Data stored in the postprocessing dataset (if any) corresponds to the previous postprocessing parameters.

  • processing, indicating that a postprocessing job is ongoing. Data stored in the postprocessing dataset corresponds to the current postprocessing configuration but might be incomplete.

  • finished, indicating that a postprocessing job has been completed. Data stored in the postprocessing dataset corresponds to the current postprocessing parameters.

• command = <command> is a write-only parameter that controls the execution of the postprocessing job. The status parameter is reported upon issuing a command. <command> can be one of:

  • enable starts the post-processing job (only if the status is disabled)

  • stop stops the post-processing job (indicate completion)

  • reset return back to the disabled state (doesn't clear the dataset)

The command reset will not discard the dataset.  However, if the memory is cleared (either via memclear or via enable erasememory = true), dataset-4 will be discarded once the memory is erased: the dataset is always associated with the relevant dataset-1.  Changing postprocessing parameters is not allowed while status is processing or finished. In order to change any parameters, a reset needs to be issued to go back to the disabled status.

The finished status indicates previously processed data and current postprocessing parameters are the ones used to process the dataset.

postprocessing allows calculating dynamic correction for salinity and marine temperature channels on RBRargo C.T.D.  A special suffix (_dyn_corr) is added to the channels label to expose their dynamically corrected version:

• salinity_00_dyn_corr

• temperature_00_dyn_corr

This method is not recommended anymore as the algorithm used assumes a constant ascent rate and firmware 1.145 provides a salinity channel with dynamic correction applied based on the instantaneous ascent speed.

• dc_tau [= <value>]  is the C-T lag for dynamic correction of the salinity.

• dc_alpha[= <value>] is the magnitude of short-term thermal mass correction for dynamic correction of the salinity.

• dc_tdelay[= <value>] is a dynamic correction parameter for the time lag correction (in seconds) between marine temperature and conductivity cell temperature

• dc_ctcoeff[= <value>] is the magnitude of long-term thermal mass correction for dynamic correction of the salinity.
  
  

Examples

>> postprocessing
<< postprocessing status = finished, mode = continuous, channels = mean(conductivity_00)|mean(temperature_00)|mean(pressure_00)|mean(salinity_00_dyn_corr)|mean(temperature_00_dyn_corr)
>> postprocessing all
<< postprocessing status = finished, mode = continuous, channels = mean(conductivity_00)|mean(temperature_00)|mean(pressure_00)|mean(salinity_00_dyn_corr)|mean(temperature_00_dyn_corr), dc_alpha = 0.1300, dc_tau = 5.9000, dc_tdelay = 0.3500, dc_ctcoeff = 1.0200e-00

>> postprocessing status
<< postprocessing status = disabled
>> postprocessing command = enable
<< postprocessing status = processing
...[ postprocessing active ] ...
>> postprocessing status
<< postprocessing status = finished

>> postprocessing dc_tau = 7.00
<< postprocessing dc_tau = 7.00
>> postprocessing dc_alpha
<< postprocessing dc_alpha = 0.08

Errors

Error E0108 invalid argument to command
The command was given with an argument which is unrecognized or has an invalid value; for example

Error E0425 invalid settings
Post-processing can not start because some settings are inconsistent or invalid.

Error E0426 postprocessing already active
Parameters cannot be changed while the post-processing status is not idle.

Error E0427 wrong memory format
The current dataset is not stored using the calbin00 memory format.

Error E0428 postprocessing reference channel not available
One of the supporting channels required is not available in the current dataset.