canFMSGetPGN (Function)

This function can be used to extract the FMS/J1939 PGN from a CAN message received with canReceiveMessage.

To create a CAN filter from a PGN, please see canFMSFilterCreate.

Input:

Id   : DINT (16#0...16#FFFFFFFF) (Default 0)

The CAN message ID to extract PGN from.

Returns: DINT

Declaration:

FUNCTION canFMSGetPGN : DINT;
VAR_INPUT
  Id    : DINT := 0;
END_VAR;

Example:

INCLUDE rtcu.inc
 
VAR
  can   : canReceiveMessage;
  buf   : ARRAY[1..8] OF SINT;
END_VAR;
 
FUNCTION_BLOCK ParseCruiseControl;
VAR_INPUT
  data   : PTR;
END_VAR;
VAR_OUTPUT
  speed : DINT;     // Wheel based speed (SPN84)
  clutch : BOOL;     // Clutch switch (SPN 598), TRUE=pressed, FALSE=released
  break : BOOL;     // Break switch (SPN 597), TRUE=pressed, FALSE=released
  cruise : BOOL;     // Cruise control active (SPN 595), TRUE=switched on, FALSE=switched off
  val   : SINT;     // Unknown data in byte 7. (SPN 976)
END_VAR;
VAR
  can   : ARRAY [1..8] OF SINT;
  temp   : SINT;
  high   : DINT;
END_VAR;
  // Copy CAN data to local buffer
  memcpy(dst := ADDR(can), src := data, len := 8);
 
  // Extract Wheel based speed.
  speed := shl32(in := can[2], n := 8) + can[3];
 
  // Extract Clutch switch
  IF shr8(in := can[4], n := 6) = 1 THEN
     clutch := TRUE;
  ELSE
     clutch := FALSE;
  END_IF;
 
  // Extract Break switch
  temp := shr8(in := can[4], n := 4) AND 16#03;
  IF temp = 1 THEN
     break := TRUE;
  ELSE
     break := FALSE;
  END_IF;
 
  // Extract Cruise control active
  IF (can[4] AND 16#03) = 1 THEN
     cruise := TRUE;
  ELSE
     cruise := FALSE;
  END_IF;
 
  // Extract Unknown data
  val := can[7] AND 16#1F;
END_FUNCTION_BLOCK;
 
FUNCTION ParseEngineSpeed : DINT;
VAR_INPUT
  data : PTR;
END_VAR;
VAR
  can : ARRAY [1..8] OF SINT;
  tick : DINT;     // Engine speed (SPN190)
END_VAR;
  // Copy CAN data to local buffer
  memcpy(dst := ADDR(can), src := data, len := 8);
 
  // Extract engine speed
  tick             := shl32(in := can[4], n := 8) + can[5];
  ParseEngineSpeed := tick * 125/1000; // Convert from ticks to RPM's
END_FUNCTION;
 
PROGRAM example;
VAR
  PGN : DINT;
  CCVS : ParseCruiseControl;
END_VAR;
 
  // Initializing
  canOpen(baud := 250);
  can.data := ADDR(buf);
  canFMSFilterCreate(PGN := 65265);
  canFMSFilterCreate(PGN := 61444);
 
BEGIN
  can();
  IF can.ready THEN
     PGN := canFMSGetPGN(id := can.id);
    IF PGN = 65265 THEN
        CCVS(data := ADDR(buf));
        DebugFmt(message := "speed= \4", v4 := CCVS.speed);
        DebugFmt(message := "clutch= \1", v1 := INT(CCVS.clutch));
        DebugFmt(message := "break= \1", v1 := INT(CCVS.break));
        DebugFmt(message := "cruise= \1", v1 := INT(CCVS.cruise));
        DebugFmt(message := "unknown= \1", v1 := CCVS.val);
    ELSIF PGN = 61444 THEN
        DebugFmt(message := "rpm= \4", v4 := ParseEngineSpeed(data := ADDR(buf)));
    END_IF;
  END_IF;
END;
 
END_PROGRAM;