Symbol Table Database Search Help

Search the Database

The Search page allows the user to set up search parameters using the form interface. After setting up the search parameters hit the Start Search button to begin the search.

Review the Results

The Search Results page lists all the symbols filtered by the search parameters. Presented in table form, most of the basic information is given in the table. The symbol name is actually a link which will bring up the Results Detail page, giving all the information about that symbol.

Examine a Symbol's Details

The Results Detail page displays all the information about the symbol in the database.

Description of Database Elements

1- Symbol Name

This is the root name of the symbol. This name is used to create names for variables, functions, and #defines. Substitutions are used to keep the symbol table small. For example, sometimes this element will contain {Arm}, this will be replaced by the appropriate arm code (like Dxl for Dexterous left arm). Since all of the robotic manipulators have similar message structure this substitution reduces the size of the symbol table considerably. The Search Results and Record Detail pages display this name. The Search page allow the user to type in part of the symbol name to be searched upon.

2- Data Type

This element describes the C code data type. Standard C data types and structures are used in the symbol table. The Search Results and Record Detail pages display the specific data type for that symbol. The Search page allows the user to select from the complete list of data types currently used by the symbol table and find only the symbols with the appropriate data type.

3- Array Size

The size of the array is given in this field. If no array size is displayed than that symbol is not an array. Multidimensional arrays are not used in the symbol table, either a single variable or a one dimensional array will be defined.

4- Units

This field displays what units are used in the values of a symbol. For structures or arrays, different units may be defined for the different elements of the structure.

5- NDDS Message

This is the root name used to create variable names for producers and consumers for NDDS(Network Data Delivery Service). If NDDS is not used this element is not necessary. The NDDS message name is derived from the subsystem name. If the last character in the name is a number, than the message is characterized as a command. Commands are typically messages sent from a control station to a robotic vehicle. Telemetry messages is denoted when the last character in the NDDS message name is a letter. Telemetry is defined as messages from the robotic vehicle to a control station. All symbols are characterized as one of the above two groups, although some messages do not exactly fit into those groups. The Search page allows the users to type in part of a message name to be search upon.

6- Subsystem

This is the name of the subsystem that a symbol is group in. These groups hold several symbols which are related to each other in functionality or type of system they control. These subsystem names are used as define flags for a computer project with allows that application to use only the symbols it needs, ignore the rest of the symbol table. The Search page allows a user to pick from the list of all current subsystems and find the symbols associated in those groups. A description for each subsystem can be read. Each variable is associated with only one subsystem.

7- Symbol Value Info

Each symbol is related to a message which holds a variable. The ranges and typical values of the variable are given in the Symbol Value Info box. Each field with in the box is described below:

 Default Value:  This is the original value which is initialized with the variable
 Minimum:  This is the minimum value which the variable will obtain. Below this value an error has occurred.
 Lower Red Warning:  This is the lowest operational warning threshold for the variable. Below this value the operator will be notified that an error has occurred.
 Lower Yellow Warning:  This is a low operational warning threshold, below this value the operator may be notified of the warning.
 Upper Yellow Warning:  This is an upper operational warning threshold, above this value the operator may be notified of the warning.
 Upper Red Warning:  This is the highest operational warning threshold for the variable, above this value the operator will be notified that an error has occurred.
 Maximum:  This is the maximum value which the variable will obtain. Above this value an error has occurred.

8- Data Rate

The data rate is the frequency, in Hertz, that the message is transmitted when using the UDP communication protocol, like NDDS. On the Record Detail page three rates are given, by default the medium rate is used. Most message are sent a some rate, even infrequently updated messages are sent a constant rate due to the unreliability of UDP. Some messages, however, are only sent when a certain event occurs. These event driven messages are denoted as "queued only", since the message must be queued by something to be sent. Data rate values are not used when the shared memory protocol is in use. The Search page allows a user to search for queued only message by clicking the checkbox. Also searches can be made on specific values or ranges of data rates by using the text field and associated pop up menu.

9- Symbol Type

As described before, symbol's are split into two categories: command and telemetry. Command symbols are typically sent from a control station to a vehicle system. Telemetry symbols are sent from the vehicle to be displayed on a control station. Although some symbols do not exactly fit perfectly into these categories, all are defined as one or the other. The symbol type field display which category a symbol is. For telemetry symbols, more designation is required. There are three groups which telemetry fall under: derive, verify, and raw. The table below describes each symbol type designation.

 Command  A symbol sent from a control station module to a system to command some part of that system.
 Derive  The most common telemetry symbol sent from the computer on-board a system to a control station module.
 Verify  A telemetry symbol used as a receipt of an incoming command symbol. This symbol echoes the associated command back to the control station.
 Raw  A telemetry symbol which was read from memory on board a system. These raw symbols are typically direct readings from sensors. No conversions or any manipulation has been performed on a raw symbol, once a conversion occurs that symbol is deemed a derived symbol. Raw symbols are used to debug hardware by looking at what is being read from hardware into memory.

10- Description

A description of that symbol is given in the Record Detail page. This explains the purpose of the symbol and how it is used. If the symbol is an array or structure, each element of the array or structure is summarized as well.

11- Start New Search

This link on the Search Results page, returns the user to a new Search page. If the current search is to be modified, use the back button, or the go menu, on the internet browser to return to the previous Search page. Then modify the search parameters as desired.

12- Boolean Combinations

These radio buttons allows the user to use combinations of search parameters. Defaulting to AND, combination limit the size of the data set recovered. Therefore symbols which are in the Bcs subsystem and are Command type could be listed. Be careful with the AND setting since its easy to find no results. For instance, no set will appear if the search parameters are looking for float and double data types. Since no symbol is both a float and a double. The same is true for the subsystems list, the symbol type checkboxes, and the data rate items. Use the OR radio button to achieve this, symbols which are float or double data type will the be selected.

13- Maximum Records Display Menu

By default, all the found records will be displayed on the Search Results page. A maximum number of displayed records can be chosen by this pop up menu. The Search Results page will the use buttons and links to page through the list of records.

14- Start Search Button

This button initiates the search, reading the form to determine the search parameters, then displaying the results in the Search Results page.

15- Find All Records Button

This button will display all the records in the database on the Search Results page.

16- Reset this form

This button resets the search parameters on the form. New parameters can then be assigned using the form.