Radio Link components are a round-about means of creating a 'global variable' in PSCAD. The data is transmitted by inputting a data signal directly into a transmitter, which may then be 'received' at any location within the project by a receiver bearing the same name.
Radio Links circumvent the need to add external port connections (along with Import or Export components) to pass data signals between modules. As a matter of fact, Radio Links allow data signals to be transferred directly between multiple module levels. Although bidirectional transmission of data is allowed (i.e. either down or up multiple module levels), there are issues regarding time step delay that should be considered (see Time Step Delay Issues below for more).
Radio links may also be used to plot signal data without the use of an output channel, but only to plot end-of-run data, not during runtime. This is useful in the specific situation where you are running a master-slave simulation (see Root Control Interface). See the Robust Optimization workspace in the PSCAD examples folder for an example on this.
To plot the data from a radio link, either right-click the radio link and add it as a curve, or drag and drop it directly onto a graph. See Curves and Drag and Drop for more details on this.
Important Points to Remember:
Each global variable can be defined by only one distinct transmitter.
Transmitters cannot exist in multiple instance modules.
Each global variable can have 0 to n corresponding receivers.
All global variables are REAL numbers. If INTEGER signals need to be passed, then it is possible to convert the signal on either end with no loss of information.
Transmitters cannot be connected directly to output signals created by receivers.
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Transferring Data Into and Out of Modules |
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Definition |
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Specify the namespace (project) and definition where the corresponding transmitter is located (syntax: namespace:definition). If the namespace is omitted, then the current project is assumed.
This field is enabled only when Mode | Receive is selected. |
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Mode |
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Choice |
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Select Receive or Transmit.
This input defines whether the component is to be a receiver or transmitter. |
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Inter Project Transfer? |
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Choice |
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Select Yes or No.
Select Yes for root control simulations so that radio link transfers data between master and slave projects. Note that when Yes is selected, the signal is interpreted as a constant. |
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Rank |
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INTEGER |
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Enter the rank number of the simulation associated with this radio link.
The rank number is an identifier for simulation instances launched in a volley. A rank number of 0 is specified in the slave to indicate that it should only receive transmitted data matching it's rank number. A rank of 0 is specified in the master to indicate it is always transmitted. For more information on this, see Rank Number in the Parallel and High Performance Computing topic.
This field is enabled only when Inter Project Transfer? | Yes is selected. |
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Name |
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Enter a name for the signal being transmitted or received. NOTE: Only one transmitter with this specific name may exist in a single module. All receivers in the project baring this Name and Definition will receive the same signal from the indicated transmitter. |
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Data Type |
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Choice |
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Select Real or Integer. This input must match the input signal type. |
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Dimension |
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INTEGER |
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Enter the dimension (i.e. array size) of the incoming signal. For a transmitter, this is the dimension of the input signal to be transmitted. For a receiver, this is the dimension of the transmitted signal being received. |
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Lower Limit |
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REAL |
Literal |
Enter a value to control the minimum display limit on devices such as Meters, Polymeters and Phasormeters. |
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Upper Limit |
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REAL |
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Enter a value to control the maximum display limit on devices such as Meters, Polymeters and Phasormeters. |