ADVANCED: mbusReceive (Function)

This function is used to receive raw M-Bus frames.

For M-Bus, the frame must be requested using mbusDataRequest or mbusSend, and this function will block for a moment while it tries to read the response.

Wireless M-Bus devices may automatically send the frames and the timeout parameter can be used to determine how long this function should wait for a response.

The filter parameter can be used to only receive frames from a specific wireless M-Bus device.

Input:

handle : SYSHANDLE

A handle to the connection

frame : PTR

The buffer to store the frame in.

maxsize : INT

The size of the buffer in bytes.

filter : STRING

For Wireless M-Bus only: Specifies the address or address filter to receive frames from.

timeout : INT Default 0

Number of seconds to wait for a Wireless M-Bus frame. Use 0 seconds to return immediately if there is no data in the buffer.

Output:

size : INT

The number of bytes received.

Returns: INT

Declaration:

FUNCTION mbusReceive : INT;
VAR_INPUT
  handle   : SYSHANDLE;
  frame   : PTR;
  maxsize : INT;
  filter   : STRING;
  timeout  : INT:=0;
  size     : ACCESS INT;
END_VAR;

Example:

// Dump all received frames from ELS meters, to e.g. help with debugging.
INCLUDE rtcu.inc
// Uncomment math.inc to add math library support.
//INCLUDE math.inc
 
//  These are the global variables of the program
VAR
  mb : SYSHANDLE;
 
END_VAR;
 
PROGRAM wmbus_raw_rec;
// These are the local variables of the program block
VAR
  rc       : INT;
  len      : INT;
  rx_frame : ARRAY [1..300] OF USINT;
  str      : STRING;
  i        : INT;
END_VAR;
// The next code will only be executed once after the program starts
 
  rc := mbusOpen(type:=2, handle:=mb, mode:=_MBUS_MODE_T1_C);
  DebugFmt(message:="mbusOpen(): \1", v1:=rc);
 
  // Receive from all devices
  rc := mbusFilterEnable(handle:=mb, enable:=FALSE);
  DebugFmt(message:="mbusFilterEnable(): \1", v1:=rc);
 
BEGIN
  // Code from this point until END will be executed repeatedly
 
  // Filter will only receive from ELS meters (16#1593)
  rc := mbusReceive(handle:=mb, filter:="FFFFFFFF9315FFFF", frame := ADDR(rx_frame), maxsize:=300, size := len, timeout:=30);
  DebugFmt(message:="mbusReceive(): \1, len=\2", v1:=rc, v2:=len);
  IF rc = 1 THEN
    str :="";
    FOR i := 1 TO len DO
        str := str + sintToHex(v:=rx_frame[i])+" ";
        // Break up string after 32 bytes
        IF i MOD 32 = 0 THEN
          DebugMsg(message:=str);
          str := "";
        END_IF;
    END_FOR;
    DebugMsg(message:=str);
  END_IF;
  Sleep(delay:=1000);
END;
 
END_PROGRAM;