FB_BA_LogMessage

The function block outputs messages in the TwinCAT display window.

The symbol path of the function block is inserted for each message to be output so that the user can recognize the calling function block instance by the message.

Instances of this function block cannot be called explicitly. Separate functions are available for various application cases, which are described in the following section of this documentation.

The functionality to output messages is provided by the ADSLOGDINT function, which is used internally.

VAR_OUTPUT

sResult     : T_MaxSTRING;

sResult: Content of the message last output.

Application

Context-related additional information

The developer has the possibility to output an abbreviation in each message.

Using this abbreviation, messages can be localized more easily in the source code (e.g. when searching for the abbreviation using the search function).

Suppression of cyclically repeated messages

In order to suppress the cyclic output of the same message, the current log code is compared with the log code used last. If the two values correspond, the output of the message is suppressed, which conversely means that different successive messages would be displayed.

This behavior can be influenced with the bIgnoreBlock option from the Show function:

TRUE prevents the suppression of a cyclically repeated message.

Example 1:

The example function DoWork() outputs a warning in row 150:

FUNCTION_BLOCK FB_TEST
VAR
  fbLogMsg   : FB_BA_LogMessage;
END_VAR

FUNCTION DoWork

fbLogMsg.Show(ADSLOG_MSGTYPE_WARN, 'DW150', 'Function not ready.', FALSE;

Example 2:

The example function Init() outputs an error message in row 80 that could be Suppression of cyclically repeated messages

FUNCTION_BLOCK FB_TEST
VAR
  fbLogMsg   : FB_BA_LogMessage;
  iState     : INT := 0;
  sDevice    : STRING := 'CX9020';
END_VAR

FUNCTION Init

fbLogMsg.Show1(ADSLOG_MSGTYPE_ERROR, 'I80', 'device %s has an  Invalid state "%d".', F_STRINGEx(sDevice), F_INT(iState), TRUE;

Requirements