sampling

Usage

>> sampling [<parameter> =<value>,...]

Security

Description

1. schedule [=<index>] reports or sets the index of the schedule to be read or modified. At the present time the logger supports only a single schedule, and the value of the <index> must always be 1.

2. mode [ = continuous | burst | wave | average | tide | regimes ] reports or sets the sampling mode for the current schedule.
   

   1. continuous mode is supported by all loggers; measurements are taken and stored at the specified period between the start and end times.

   2. burst mode is available for loggers which are so configured in the factory; measurements are taken and stored in bursts between the start and end times. The time between the start of two consecutive bursts is given by the burstinterval, the number of measurements in the burst is given by the burstlength, and the time between measurements within the burst is given by the period.

   3. wave mode is available for loggers which are so configured in the factory, and with one exception is identical to burst mode as far as the logger's behaviour is concerned. The two modes are distinct to allow host software to process the burst measurements for wave applications. The exception is that the altitude command is available only when the logger is capable of the wave sampling mode.

   4. average mode is available for loggers which are so configured in the factory. It works identically to burst mode, except that instead of storing every measurement in the burst, the average value of all measurements is computed and stored as a single sample value at the end of the burst.

   5. tide mode is available for loggers which are so configured in the factory, and is identical to average mode as far as the logger's behaviour is concerned. The two modes are distinct to allow host software to process the data for tide monitoring applications.

   6. regimes mode is available for all loggers, but is intended for vehicle integration. Instead of a deployment containing a single sampling period, averaging burstlength, etc, the regimes mode permits multiple sampling periods, averaging bins, and sampling periods to be set for different environmental conditions-pressure regimes.

   7. ddsampling mode is available for all loggers, but is mainly intended for vehicle integration. Instead of a deployment containing a single sampling period, the ddsampling mode permits two sampling periods depending on the the current direction of the logger (descending or ascending). See command ddsampling.

3. period [=<period>] reports or sets the time between measurements.
   This is straight forward in continuous mode; in any of the other modes it is the time between continuous measurements within the burst. The <period> is specified in milliseconds.
   
   Values for 1Hz sampling or slower are supported by all loggers, and must be given in multiples of 1000. In continuous mode the permitted range is typically 1000 (one second) to 86400000 (24 hours), in increments of 1000. Some loggers may have a lower limit which is more than 1000 if an attached sensor has a very slow data acquisition time. For all other modes the upper limit is 255000 (about 4 minutes); this is unlikely to be a constraint in practice, as the period is the time between measurements within the burst.
   
   If the logger is configured to support fast (sub-second) measurement periods for the selected mode, the <period> must correspond to an exact frequency in Hz, to the nearest millisecond. Permitted values may be further constrained as follows, according to the firmware version:
   
   Firmware versions up to and including 1.360:
   |fast 6 - 500(2Hz), 333(3Hz), 250(4Hz), 200(5Hz), and 167(6Hz)
   |fast12 - All |fast6 values plus 83(12Hz).
   Firmware versions later than 1.360:
   |fast 6 - 500(2Hz), 250(4Hz), and 167(6Hz)
   |fast16 - All |fast6 values plus 125(8Hz), 83(12Hz), and 63(16Hz).
   |fast32 - All |fast16 values plus 42(24Hz) and 31(32Hz).
   
   Note that fast measurement periods may be supported in some modes but not others, depending on the logger's configuration.
   

   The following parameters are available only if the logger is configured to support at least one of the average, burst, tide, or wave modes.

4. burstinterval [=<burstinterval>] reports or sets the time between the first measurement of two consecutive bursts; it is not the gap between the end of one burst and the start of the next. The <burstinterval> is specified in milliseconds.

   The absolute limits of the permitted range are 1000 (one second) to 86400000 (24 hours), and the <burstinterval> must be set to a multiple of 1000. However, before the logger can be enabled for sampling the value set must also be consistent with the measurement period and burstlength.
    

5. burstlength [=<burstlength>] reports or sets the number of measurements taken in each burst.
   The permitted range is 1 to 65535, but before the logger can be enabled for sampling the value set must also be consistent with the measurement period and burstinterval.
   The constraining relationship between the burst parameters is: burstinterval > (burstlength * period).

   The following read-only parameter is available only if the logger is configured to support at least one of the gating conditions for sampling.

6. gate reports any gating condition currently enabled.
   A gate is an extra requirement that must be satisfied before sampling will occur, in addition to the logger's current time being between the start and the end times. The following gating conditions are presently defined:
   

   1. none: no gating conditions are enabled.

   2. thresholding: a threshold requirement must be satisfied; see the thresholding command.

   3. twistactivation: the end-cap must be in the "on" position; see the twistactivation command.

   4. invalid: two or more gating conditions have been selected, this is not currently possible and will prevent the logger from being enabled.

   For further information about gated sampling, see the section Gated Sampling.

   The following read-only parameter is available only if the logger is configured to support 'fast' sampling, in which the period can be less than 1000ms.

   
   

7. userperiodlimit reports the minimum period which can be used in 'fast' sampling modes, in milliseconds; the period can not be set to a value less than this.

Examples

The logger has been programmed for continuous 6Hz sampling.The programmed values of the burst parameters are reported but do not apply to continuous sampling. No gating condition is in force.

  Averaging enabled without changing the other parameters; the logger is now programmed to take a burst of 60 measurements at 6Hz every five minutes, and store the average of the 60 measurements.

  The mode is changed to burst recording and the burst interval to ten minutes; the logger is now programmed to take a burst of 60 measurements at 6Hz every ten minutes, storing all measurements in memory.

The logger has been programmed for continuous 4Hz sampling. This logger does not support any of the other modes, so the parameters are not reported.

Errors

Error E0105 command prohibited while logging
Settings may not be modified while logging is in progress; reading them is permitted.

Error E0108 invalid argument to command: '<invalid-argument>'
The command was given with an argument which is unrecognized or has an invalid value; for example "sampling mode = mean", or "sampling schedule = 2".

Error E0109 feature not available
An attempt was made to use a feature which the logger is not configured to support; for example "sampling mode = average" if the logger does not support averaging.