channel

Usage

>> channel <index> [ type | module | status [ = on | off ] | latency | readtime | equation | userunits | gain [ = <gain-setting>] | gainsavailable | derived

Security

Description

Returns information about the channel at the specified <index>: the first channel has an <index> of 1.

A special value of all may be given for the channel <index>, causing the requested parameters to be reported for all channels. The output for each channel is terminated by a vertical bar character '|', except for the last channel which is terminated by a <cr><lf> pair as normal. The following parameters give the basic information available for all channels. None of these values may be modified by end users. 

1. type is a short, pre-defined 'generic' name for the installed channel; for example:
   1. temp09  RBRduo temperature,
   2. pres19  RBRduo pressure,
   3. cond05  RBRconcerto marine conductivity,
      and so on. RBR Ltd continually adds support for more sensor types and variants; the Section Supported Channel Types contains a complete listing of channel types available at the time of writing this document.
2. module is the internal address to which this channel responds; it is normally of no interest to end users.
3. latency is the minimum power-on settling delay in milliseconds required by this channel, taking into account both the sensor and the interface electronics.
4. readtime is the typical data acquisition time in milliseconds required by this channel, again taking into account both the sensor and the interface electronics.
   Most channels have a fixed, pre-determined readtime, but for some it may be variable. An example would be a channel which supports, and is configured to use, the auto-ranging feature: the readtime is longer when the channel is in auto-ranging mode than when operated in a fixed-gain mode. The logger adjusts the reported value of the readtime to reflect the operating mode and status of the channel. 
5. equation is the type of formula used to convert raw data readings to physical measurement units. The values for the core equations are shown below as examples; see the section Calibration Equations and Cross-channel Dependencies for details of all supported equations.
   1. tmp  temperature
   2. lin  linear
   3. qad  quadratic polynomial
   4. cub  cubic polynomial
6. userunits is a short text string giving the units in which processed data is normally reported from the logger; for example C for Celsius, V for Volts, dBar for decibars, etc. Presently this is a factory-set field representing the fundamental units in which the channel is calibrated; support for user-selectable units is planned in the future.

7. derived is a flag which is either on or off to indicate whether the channel is a derived channel (on) or a measured channel (off). This is an intrinsic property of the channel type, and can not be modified: it is for information only.
   

8. gainsavailable reports the gain settings supported by the sensor at channel <index>. The settings are given as a list of numerical values in order of increasing gain, with a vertical bar character '|' separating the values. If the channel at <index> does not support multiple gain settings, the response is none.

The following parameters can be changed by end users, if and when appropriate.

1. gain reports the gain setting currently in use by the channel at <index>. In addition to one of the fixed values from the list reported by the gainsavailable option, the response may indicate auto for auto-ranging. In this mode the channel will select the most appropriate gain setting depending on the value of the parameter being measured. Again, if the channel does not support multiple gain settings, the response is none.
   
   The gain option may also be used to set the gain used. For a fixed gain setting, the value supplied must be from the list reported by the gainsavailable option. For auto-ranging, use the word auto. Although they are typically whole numbers, gains are reported in a floating point format, and may be specified as such, as long as the value appears in the list of available gains.

   The gainsavailable and gain parameters are only available for channel types which support sensors having variable gain, or multiple ranges. Presently these include sensors from Seapoint, and the Cyclops series from Turner Designs, which can measure turbidity, fluorescence, and various other optical properties. For a complete list refer to the Section Supported Channel Types.

2. status is a further basic parameter which applies to all channels. It is modifiable by end users, and allows any individual channel to be turned off or on for the duration of a deployment.
   

• • on: the channel is activated for sampling; its data will be stored in memory if appropriate, and its value will appear in streamed output if streaming is enabled. However, note that if data storage is set to Standard format (rawbin00), data is never stored for derived channels, because raw data for such channels does not exist. For the same reason, data for derived channels can not be streamed if one of the raw output formats is selected.

  • off: the channel is not sampled, no data will be stored in memory or streamed for this channel.
     

    If you turn off any of the logger's channels, and intend to use RBR's Ruskin software - for example, to download data - be sure to use the latest version of Ruskin; earlier versions may not correctly handle channels which exist but have been turned off.

    
    

Examples

Errors

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

Error E0107 expected argument missing
An argument expected by the logger was not given with the command; for example, there must always be an <index> argument.

Error E0108 invalid argument to command: '<invalid-argument>'
This error will occur if the <index> is out of range, or if an unknown parameter is requested. Logger channels are numbered from 1 to N; zero is not valid.

Error E0111 command failed
There was a problem reading or modifying some configuration data for the specified channel; typically in response to accessing gain control information for those channels which support it. Please contact RBR Ltd for help. 

Error E0505 no channels configured
 There was a problem reading or modifying some configuration data for the specified channel; typically in response to accessing gain control information for those channels which support it. Please contact RBR Ltd for help. 

Error E0501 item is not configured
There is a problem with the configuration of the specified channel; please contact RBR Ltd for help.