LogFileCSV

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Function Block - Create a log file in CSV format for a list of variables.

- Calling this function can lead to missing several PLC cycles.
- Files are opened and closed directly by the target's Operating System.
- Opening some files may be dangerous for system safety and integrity.
- The number of open files may be limited by the target system.

Inputs

Input	Data Type See Data Types.	Range	Unit	Default	Description
LOG	BOOL	FALSE, TRUE	N/A	No default	Variables are saved on any rising edge of this input.
RST	BOOL	FALSE, TRUE	N/A	No default	Reset the contents of the CSV file.
LIST	DINT	No range	N/A	No default	ID of the list of variables to log (use VLID function).
PATH	STRING	1 to 255	N/A	No default	Path name of the CSV file. Controller flash memory SD card (PxMM) USB flash drive (PCMM2G) Shared Directory

Outputs

Output	Data Type See Data Types.	Range	Unit	Description
Q	BOOL	FALSE, TRUE	N/A	TRUE if the requested operation has been performed without error.
ERR	DINT	No range	N/A	Error report for the last requested operation. 0 (zero) is OK.

Output

Data Type

See Data Types.

Range

Unit

Description

BOOL

FALSE, TRUE

N/A

TRUE if the requested operation has been performed without error.

ERR

DINT

No range

N/A

Error report for the last requested operation.

0 (zero) is OK.

Remarks

By default, the LogFileCsv block uses:
- Semicolons ( ; ) as field separators.
- Dots ( . ) as decimal points.
- The SetCsvOpt function to modify these characters to suit specific formatting requirements.
Opening a file may be unsuccessful (e.g., invalid path or file name, too many open files, etc.)
Your application has to process such error cases in a safe way.
Valid paths for storing files depend on the controller and the type of file storage media being used.
- See:
  - File Path Conventions
  - SD Card Path Conventions
  - Shared Directory Path Conventions
  - USB Flash Drive Path Conventions
This function enables to log values of a list of variables in a CSV file.
- On each rising edge of the LOG input, one more line of values is added to the file.
- There is one column for each variable, as they are defined in the list.
The list of variables is prepared using a text editor.
- Use the VLID function to get the identifier of the list.
On a rising edge of the RST command, the file is emptied.
When a LOG or RST command is requested, the Q output is set to TRUE if successful.
- See What is the Difference between Q and OK?.
In case of error, a report is given in the ERR output.
- Possible error values are:
  - 1 = Cannot reset file on a RST command.
  - 2 = Cannot open file for data storing on a LOG command.
  - 3 = Embedded lists are not supported by the runtime.
  - 4 = Invalid list ID.
  - 5 = Error while writing to file.
Combined with real time clock management functions, this block provides a very easy way to generate a periodical log file.

Figure 1 () shows a list and a program that log values every day at 14h23m (2:23 pm).

Figure 1: Example: LogFileCSV

FBD Language Example

FFLD Language Example

IL Language Example

Not available.

ST Language Example

(* MyLOG is a declared instance of LogFileCSV function block *)
MyLOG (b_LOG, RST, LIST, PATH);
Q := MyLOG.Q;
ERR := MyLog.ERR;