Data Streaming (DSTREAM)

The DSTREAM subsystem allows the SCPI user to configure and control fast data streaming via a TCP network protocol. This documentation describes the SCPI commands to control the subsystem. Details about the TCP transfer and examples can be found in a separate documentation.

The following SCPI commands can be used to configure and control one or more streaming groups (distinguished via a GRP number). Each group has its own list of channels and a TCP port where data is provided. Each group can be configured and started individually. Some commands provide an ALL option to start/stop all configured groups.

Each streaming group has its own internal state. It can be queried using the STATe? query. The following list describes the allowed operations in each state:

INVALID: An invalid state means the streaming group does not exist, it will be automatically created when calling configuration commands such as ITEMs and PORT

CONFIG: In the configuration state, ITEMs and PORT commands can be used to configure the group. The INIT command will initialize the subsystem.

INITIALIZED: The streaming group is initialized (e.g. has an open TCP port) and is waiting for connections and the STARt command. If a configuration command such as ITEMs or PORT is executed, the state is set back to CONFIG.

RUNNING: The streaming group is actively sending data. Call STOP to enter the INITIALIZED state again.

ERROR: If one of the channels to register is unused, the whole dataset will be discarded and the DSTREAM system will be in an error state. Use :DSTream:STATe? to get more details. It can be reset using the RESet command.

:DSTream:ITEMs[<GRP>] <channel>[,<channel>[,…]]

Syntax	:DSTream:ITEMs[<GRP>] <channel>[,<channel> [,…]]
Description	Defines the ordered list of requested channels for one stream group GRP
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1 <channel> ASCII String Oxygen Channel Name None
Explanation	The user can specify a list of multiple channels. If one channel does not exist, is invalid or disabled, no channel is set for the streaming group (see system error log for more details). In addition, the following channel types are not supported: Digital channels, video channels and Rosette group channels. |
Example	Set two channels for stream group 2: AI 1/1 and AI 1/2 -> :DST:ITEMs2 "AI 1/1", "AI 1/2"

:DSTream:ITEMs[<GRP>]?

Syntax	:DSTream:ITEMs[<GRP>]?
Description	Returns the current list of requested channels for one channel group GRP
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1
Explanation	Returns NONE if no items are set
Return Format	<ASCCI String>[, <ASCII String>[, …]] | NONE
Example	Query the items of stream group 2: -> :DST:ITEMs2? <- "AI 1/1", "AI 1/2"

:DSTream:PORT[<GRP>] <PORT>

Syntax	:DSTream:PORT[<GRP>] <PORT>
Description	Configures the port number of the TCP server for a streaming group GRP
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1 <PORT> NR1 1 .. 65536 10003
Explanation	The port must be a valid TCP port. It must not be used by any other TCP server on the local system but can be shared by multiple streaming groups of the Oxygen instance.
Example	Set the TCP port for stream group 2 to 10005: -> :DST:PORT2 10005

:DSTream:PORT[<GRP>]?

Syntax	:DSTream:PORT[<GRP>]?
Description	Queries the currently configured TCP port
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1
Explanation	Returns the NR1 numeric value of the configured TCP port
Return Format	<Nr1>
Example	-> :DST:PORT2? <- 10005

:DSTream:INIT [<GRP> | ALL]

Syntax	:DSTream:INIT [<GRP> | ALL]
Description	Initializes one or all data streaming groups and opens the TCP port
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1 ALL Literal None
Explanation	The server will listen for new connection on the configured port
Example	Initializes the streaming group 1: -> :DST:INIT 1

:DSTream:STARt [<GRP> | ALL]

Syntax	:DSTream:STARt [<GRP> | ALL]
Description	Starts streaming of one or all data streaming groups
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1 ALL Literal None
Explanation	Only possible after calling INIT for the specified group(s).
Example	Start streaming for all configured streaming groups: -> :DST:STARt ALL

:DSTream:STOP [<GRP> | ALL]

Syntax	:DSTream:STOP [<GRP> | ALL]
Description	Stops streaming of one or all data streaming groups
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1 ALL Literal None
Explanation	Only possible after calling STARt for the specified group(s). After stopping, the streaming group is in INITIALIZED state.
Example	Stop streaming for all configured streaming groups: -> :DST:STOP ALL

:DSTream:DELete [<GRP> | ALL]

Syntax	:DSTream:DELete [<GRP> | ALL]
Description	Deletes a configured streaming group
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1 ALL Literal None
Explanation	The streaming group must be in config state. All ITEMs and port settings are deleted.
Example	Delete streaming group 1: -> :DST:DEL 1

: DSTream:RESet

Syntax	:DSTream:RESet
Description	Resets the data streaming subsystem
Parameter	None
Explanation	Stops the server if started, and resets the configuration to its default settings
Example	-> :DST:RES

: DSTream:STATe[<GRP>]?

Syntax	:DSTream:STATe[<GRP>]?
Description	Queries the internal state of the data streaming subsystem
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1
Explanation	Possible states are: INVALID: Streaming group does not exist CONFIG: Configuration state (allows settings of ITEMs and PORT) INITIALIZED: The streaming group has already been initialized RUNNING: The server is started and cannot be configured anymore ERROR: An error has occurred; the user needs to call RESet UNLICENSED: A valid license for the data streaming subsystem was not found
Return Format	<ASCCI String>[, <ASCII String>[, …]] | NONE
Example	Query the state of the streaming group 1 (default value): -> :DST:STATe? <- CONFIG

: DSTream:TRIG[<GRP>] {ON|OFF}

Syntax	:DSTream:TRIG[<GRP>] {ON|OFF}
Description	Configure a streaming group to send data only when a trigger is active
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1 {ON|OFF} Boolean {ON|OFF} OFF
Explanation	When this property is enabled for a streaming group, data will only be streamed during a triggered measurement, while any waveform recording trigger is active.
Example	Enable the triggered mode of streaming group 1 (default value): -> :DST:TRIG ON

: DSTream:TRIG[<GRP>]?

Syntax	:DSTream:TRIG[<GRP>]?
Description	Query the triggered property for a given streaming group
Parameter	Name Type Range Default <GRP> NR1 Group number >= 1 1
Explanation	Returns the current state of the triggered property for a stream group, possible values are ON (triggered mode is active) OFF (data is streamed continuously)
Example	Query the triggered mode of streaming group 1 (default value): -> :DST:TRIG? <- ON