Send — Control Systems/Messages And Events

Send

Control Systems / Messages And Events

Turns a signal into messages: on each of its sample hits it sends one message carrying the input’s value u, stamped with the time it was sent, on a message line. A message is consumed where it is read – by a Receive, or by a message-triggered subsystem, which runs once for each one – rather than held like a sample. With its enable port shown, it sends only on the hits whose enable is positive.

Ports

• Input u – the value each message carries, any size [m,n]. With Show enable port On it is the second input.
• Input enable – only with Show enable port On, and then the first input, as in Simulink: a message goes out on the hits where any element is greater than zero; zero and negative values send nothing.
• Output msg – a message line, whose messages are the size of u. It connects only to a block that reads messages (a Receive, or a message Trigger port’s face) and never branches.

Parameters

• Show enable port – Off (default): one input, a message on every hit. On: two inputs, the enable then u. The input count must agree: add or remove the port to match, or the run is refused with the block’s name.
• Sampling Time (s) – zero or less inherits the solver's rate; a positive value runs the block at that period.

Code export

Python, MATLAB, Java, Rust, C and C++: the message line is one fixed-capacity queue in the generated core, held beside the signals, and it keeps its reader’s policy (a Receive’s queue, or a message-triggered subsystem’s). Each call copies u to the output and pushes it onto the line’s queue (with the enable shown, when any element of the enable is positive).

VHDL, Verilog, SystemVerilog and PLC Structured Text refuse a message line by name: a hardware queue is left until a hardware design asks for one. A message line that crosses the boundary of the subsystem being exported is refused by every target.

Simulink bridge

Import and export, mapped to simulink/Messages & Events/Send. Show enable port ↔ ShowEnablePort (Off/On ↔ off/on, lossless), and Simulink moves the enable port itself. "Sampling Time (s)" does not cross: Simulink’s Send has no SampleTime parameter and runs at its input’s rate, so give the signal feeding it that rate; a rate set here stays on the ICore side and is reported.

Notes

• Stateless: each hit sends what u is then. Several messages wait on the line until their reader takes them; what is kept when they pile up is the reader’s choice (a Receive’s queue).
• Measured on R2026a: an enable of 1, −1, 0, 2, −3 on successive hits sends on the first and the fourth.