LogFileCSV

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

Inputs

Input	Data Type	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

Output	Data Type	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

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.

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.

Notes

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:
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

Not available.

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