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AnnexF/pid_st.txt
author Andrey Skvortsov <andrej.skvortzov@gmail.com>
Fri, 06 May 2016 11:01:21 +0300
changeset 1006 0668ba32de98
parent 0 fb772792efd1
permissions -rwxr-xr-x
fix C compilation warning about function prototype in __SET_EXTERNAL

Example warning:
./POUS.c:1220:3: error: function declaration isn't a prototype [-Werror=strict-prototypes]
__SET_EXTERNAL(data__->,KN_AUT,,__GET_VAR(data__->KEY_AUT.STATE_OUT));
^
compilation terminated due to -Wfatal-errors.
cc1: all warnings being treated as errors 
 FUNCTION_BLOCK PID
   VAR_INPUT
     AUTO : BOOL ;        (* 0 - manual , 1 - automatic *)
     PV : REAL ;          (* Process variable *)
     SP : REAL ;          (* Set point *)
     X0 : REAL ;          (* Manual output adjustment - *)
                          (* Typically from transfer station *)
     KP : REAL ;          (* Proportionality constant *)
     TR : REAL ;          (* Reset time *)
     TD : REAL ;          (* Derivative time constant *)
     CYCLE : TIME ;       (* Sampling period *)
   END_VAR
   VAR_OUTPUT XOUT : REAL; END_VAR
   VAR ERROR : REAL ;        (* PV - SP *)
       ITERM : INTEGRAL ;    (* FB for integral term  *)
       DTERM : DERIVATIVE ;  (* FB for derivative term *)
   END_VAR
   ERROR := PV - SP ;
   (*** Adjust ITERM so that XOUT := X0 when AUTO = 0 ***)
   ITERM (RUN := AUTO, R1 := NOT AUTO, XIN := ERROR,
          X0 := TR * (X0 - ERROR), CYCLE := CYCLE) ;
   DTERM (RUN := AUTO, XIN := ERROR, CYCLE := CYCLE) ;
   XOUT := KP * (ERROR + ITERM.XOUT/TR + DTERM.XOUT*TD) ;
 END_FUNCTION_BLOCK
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