Loop.csp

-----------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------
-- Loop.csp
--
-- AUTHORS: 	Dusko S. Jovanovic
-- DATE:        2006           
-- PUBLISHED:   Designing dependable process-oriented software: a CSP-based approach.
--              Centre for Telematics and Information Technology (CTIT).
--				University of Twente. Netherlands.
--              CTIT Ph.D.-thesis series No. 06-82, pp. 114-117, 2006.
-- DESCRIPTION
-- This example describes a basic closed loop system. The loop controller manages 
-- on basis of the setpoint reference from a sequence controller and feedback signal  
-- from a controlled object the steering values to the controlled object.
-----------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------

-----------------------------------------------------------------------------------------
-- SOURCE CODE (adapted version)
-----------------------------------------------------------------------------------------
datatype Double = step_val | p_val | x_val
channel steering : Double
channel reference : Double
channel state : Double

MAIN = ParClosedLoop

ParClosedLoop = LoopConProcess [|{|reference, steering, state|}|] (SeqConProcess ||| PlantDynProcess)

SeqConProcess = reference!step_val -> SeqConProcess

LoopConProcess = reference?sp -> state?mv -> steering!p_val -> LoopConProcess

PlantDynProcess = state!x_val -> steering?u -> PlantDynProcess