Signal Generator (v2)

The signal.v2 node-type is a simple signal generator which can be used to generate sine, square, ramp, triangle or random signals at user definable frequencies, rates, amplitudes. Its a re-implementation of the original signal node-type which just changed the way of configuration.

Most commonly it is used for testing when no real simulation data is available.

Note: There is also the villas-signal tool which has a similar purpose.

Prerequisites

This node-type does not have any special library dependencies. It is always available.

Implementation

The source code of the node-type is available here: https://github.com/VILLASframework/node/blob/master/lib/nodes/signal_v2.cpp

Configuration

realtime	boolean Default: true Pace the generation of samples by the rate setting.
limit	integer Default: 0 Stop the node after the provided number of samples.
rate	number The rate at which the samples are generated if operating in real-time mode (See realtime option).
monitor_missed	boolean Default: false Raise warnings if the signal generator fails to operate in real-time due to missed deadlines.
	object (Input configuration (received by VILLASnode))
vectorize	integer Default: 1 This setting allows to send multiple samples in a single message to the destination nodes. The value of this setting determines how many samples will be combined into one packet.
	Array of Hook Object (object) or Hook Name (string) (hook_list)
builtin	boolean (Builtin hook functions) Default: true By default, each node and paths has a couple of default hooks attached to them. With this setting the attachment of built-in hooks can be disabled.
	object (Output configuration (sent out by VILLASnode))

{

• "realtime": true,
• "limit": 0,
• "rate": 0,
• "monitor_missed": false,
• "in": {

  • "signals": [

    • {

      • "signal": "random",
      • "amplitude": 1,
      • "frequency": 1,
      • "phase": 0,
      • "pulse_width": 1,
      • "pulse_low": 0,
      • "pulse_high": 1,
      • "stddev": 0.2,
      • "offset": 0,
      • "name": "Bus123_U",
      • "unit": "V",
      • "type": "integer",
      • "init": 0,
      • "enabled": true

      }

    ],
  • "vectorize": 1,
  • "hooks": [

    • "print",
    • {

      • "type": "limit_rate",
      • "rate": 1000

      }

    ]

  },
• "vectorize": 1,
• "hooks": [

  • "print",
  • {

    • "type": "limit_rate",
    • "rate": 1000

    }

  ],
• "builtin": true,
• "out": {

  • "vectorize": 0,
  • "hooks": [

    • "print",
    • {

      • "type": "limit_rate",
      • "rate": 1000

      }

    ]

  }

}

Example

node/etc/examples/nodes/signal-v2.conf

nodes = {
    signal_node = {
        type = "signal.v2"

        rate = 10.0

        # Wait between emitting each sample
        realtime = true

        # Only emit 1000 samples, then stop
        limit = 1000

        # Count and warn about missed steps
        monitor_missed = true

        in = {
            signals = (
                { name = "sine1",   signal = "sine",   amplitude = 123.456, frequency = 10, offset = 1.0   },
                { name = "sine2",   signal = "sine",   amplitude = 12.456,  frequency = 20, offset = 10.0  },
                { name = "sine3",   signal = "sine",   amplitude = 2,       frequency = 1,  offset = 100.0 },
                { name = "random1", signal = "random", amplitude = 2, stddev = 2,           offset = 13.0  },
                { name = "pulse1",  signal = "pulse",  frequency = 1.0, pulse_width = 1, pulse_high = 100, pulse_low = 50 }
            )
        }
    }

    signal_node2 = {
        type = "signal.v2"

        in = {
            signals = {
                count = 8
                signal = "mixed"
            }
        }
    }
}