Access the Citadel Web Service
- Updated2025-11-07
- 3 minute(s) read
The LabVIEW Datalogging and Supervisory Control (DSC) Module includes the following Historical VIs and Tags VI for the nicitadel web service.
The nicitadel web service exposes these VIs:
- Alarm & Event Query (queries alarms only)
- Get Computer List
- Get Database List
- Get Trace Info
- Get Trace List
- Read Trace
Specifying the URL
You use a URL and HTTP methods to interact with the nicitadel Web service. Refer to the following table to specify the URL pattern, which consists of the Web method and tag URL, and input parameters of the URL. Input parameters are case sensitive.
| Description | URL pattern | HTTP method | Input parameters |
|---|---|---|---|
| Queries a list of computers on the local network. | computerlist | GET | OUTPUT_FORMAT={XML, JSON} (XML) |
| Queries a list of databases on the computer you specify in <computer>. | databaselist/<computer> | GET | OUTPUT_FORMAT={XML, JSON} (XML) |
| Queries a list of traces. | tracelist | GET | dbpath=DB_SERVER/DB_PATH (localhost/Default_Database)OUTPUT_FORMAT={XML, JSON} (XML) |
| Queries trace information. | info/<tag_URL> | GET | dbpath=DB_SERVER/DB_PATH (localhost/Default_Database)OUTPUT_FORMAT={XML, JSON} (XML) |
| Queries trace data. | trace/<tag_URL> | GET | start=TIMESTAMP (Timestamp of the first data point) end=TIMESTAMP (Timestamp of the last data point) dbpath=DB_SERVER/DB_PATH (localhost/Default_Database)maxItems=INTEGER (–1)decimate=BOOLEAN (FALSE)OUTPUT_FORMAT={XML, JSON} (XML) |
| Queries historical alarms. | alarms/<tag_URL> | GET | start=TIMESTAMP (Timestamp of the first alarm) end=TIMESTAMP (Timestamp of the last alarm) dbpath=DB_SERVER/DB_PATH (localhost/Default_Database) OUTPUT_FORMAT={XML, JSON} (XML) |
Specifying the Tag URL
You must specify the <tag_URL> as an absolute path in the following format: computer/library/variable. For example, when you invoke the info or trace Web methods, you must specify the variable name in the <tag_URL>.
When invoking the alarms Web method, you can define <tag_URL> as computer/library, computer, or unspecified. If you do not specify the <tag_URL>, the alarms Web method queries the historical alarms under the localhost and the default database.
When you specify an input parameter, use the following table to understand the values that the input parameter can accept:
| Input parameter | Input parameter value | Description | Example |
|---|---|---|---|
| dbpath | DB_SERVER/DB_PATH | Specifies the database path. DB_SERVER and DB_PATH are strings. The forward slash (/) is required. | dbpath=computer1/mydatabase |
| startend | TIMESTAMP | Specifies the timestamp. The format must be YYYY-MM-DDThh:mm:ss(+/-)time-offset, where T is a delimiter separating the date and time and time-offset is the hours and minutes ahead or behind UTC time. | start=2010-12-31T00:30:57+08:00 |
| maxItems | INTEGER | Specifies an integer. The default is –1, which means the trace Web method queries the maximum number of traces. Possible values are –1, 0, 1, 2,... If the value is greater than 2,147,483,647, the Web method queries only a maximum of 2,147,483,647 traces. | maxItems=1000 |
| decimate | BOOLEAN | Specifies a Boolean. Possible values are TRUE and FALSE. | decimate=TRUE |
The following table shows possible example URLs:
| Web method | Example URL | Description |
|---|---|---|
| computerlist | http://localhost:3580/nicitadel/computerlist?OUTPUT_FORMAT=JSON | Invokes the computerlist Web method to retrieve computers on the local network. Information returns as a JSON-formatted response. |
| databaselist | http://localhost:3580/nicitadel/databaselist/computer1?OUTPUT_FORMAT=JSON | Invoke the databaselist Web method to retrieve the list of databases on the computer computer1. |
| trace | http://localhost:3580/nicitadel/trace/computer1/library1/variable1?OUTPUT_FORMAT=JSON&dbpath=computer1/Default_Database | Invokes the trace Web method to retrieve the trace data of the trace URL computer1/library1/variable1 and database path computer1/Default_Database. |
| alarms | http://localhost:3580/nicitadel/alarms/computer1/library1?dbpath=computer1/C__Program_Files_National_Instruments_LabVIEW_2010_data | Invokes the alarms Web method to retrieve the historical alarms of the trace URL computer1/library1/variable1 and database path computer1/C__Program_Files_National_Instruments_LabVIEW_2010_data. By default, information returns as an XML-formatted response because the URL does not specify the output format. |