Receiving data from .csv file sent by WMS software

Denilson Pegaia

Hi,

if the data stay on a PC folder, it should, in theory, be possible to access it by FTP (PC as server, PLC as client). 

There is an Application & Example about FTP communication in FTP Client Communication with S7-1200/1500 

As the text the Application & Example is just an example, you will should adapt and test it by yourself...

After read (in a DB) the data should be "split" and  "translated" from ascii to int in the user program

Hi,

I think you understood me well. I only need to do 2 operations:

1. monitor the presence of the file in the native FTP folder and retrieve it once it appears there

2. delete the file as soon as the plc has finished processing its contents

So the plc acts as a client.

Now I'm going through the document regarding LFTP that you adviced me.

So far it looks promising for me. Unfortunately I still haven't received the ordered plc, so I can't test it.

One point that worries me a bit is what happens when the folder is empty (the file is placed there periodically, can be seconds or minutes, no fixed period set) and plc tries to retrieve a file on every sweep. According to the document, error 16#8400 will occur, but what will be the further consequences (crash, freeze...)?

In the current solution InTouch monitors the folder every second and sends the figures to the plc after it has retrieved them.

Monitor the output of the FTP call.  When 16#8400 is received, stop processing in the small FTP receive related FB and return to the caller no file is available (perhaps returning the 16#8400 value to the caller).

slavo_74

Hi,

I think you understood me well. I only need to do 2 operations:

1. monitor the presence of the file in the native FTP folder and retrieve it once it appears there

2. delete the file as soon as the plc has finished processing its contents

So the plc acts as a client.

Now I'm going through the document regarding LFTP that you adviced me.

So far it looks promising for me. Unfortunately I still haven't received the ordered plc, so I can't test it.

One point that worries me a bit is what happens when the folder is empty (the file is placed there periodically, can be seconds or minutes, no fixed period set) and plc tries to retrieve a file on every sweep. According to the document, error 16#8400 will occur, but what will be the further consequences (crash, freeze...)?

In the current solution InTouch monitors the folder every second and sends the figures to the plc after it has retrieved them.

 Hi Einstein,

I'm not sure if I follow you.

The thing is that I can't stop searching for the file since I never know when it may appear there.

0_Einstein

Monitor the output of the FTP call.  When 16#8400 is received, stop processing in the small FTP receive related FB and return to the caller no file is available (perhaps returning the 16#8400 value to the caller).

slavo_74

Hi,

I think you understood me well. I only need to do 2 operations:

1. monitor the presence of the file in the native FTP folder and retrieve it once it appears there

2. delete the file as soon as the plc has finished processing its contents

So the plc acts as a client.

Now I'm going through the document regarding LFTP that you adviced me.

So far it looks promising for me. Unfortunately I still haven't received the ordered plc, so I can't test it.

One point that worries me a bit is what happens when the folder is empty (the file is placed there periodically, can be seconds or minutes, no fixed period set) and plc tries to retrieve a file on every sweep. According to the document, error 16#8400 will occur, but what will be the further consequences (crash, freeze...)?

In the current solution InTouch monitors the folder every second and sends the figures to the plc after it has retrieved them.

 

Do you understand how PLCs work?
If not, then first learn how PLC logic "Scans"

If you already understand how PLC logic works, I am confused by what you are asking.

For the FTP block call you are intending to use:

There's stuff in front of a comm block that causes it to start acting, does nothing to start acting again once it started acting (is BUSY).

There's stuff on the outputs of a comm block where it provides status updates, like the block says it's DONE (new file arrived), or had an ERROR services the last request (no file exists, remote device offline or unavailable in some way, or configuration error).

It is easy to interrogate the Done/Error outputs because they are (typically) only true for a single PLC scan, allowing for error handling, or file(s) / contents handling.

If DONE THEN "CALL SOME FC TO HANDLE DATA";
If ERROR and (STATUS=16#8400) THEN
  # NO FILE EXISTS
  # JUST EXIT
END_IF;

slavo_74

 Hi Einstein,

I'm not sure if I follow you.

The thing is that I can't stop searching for the file since I never know when it may appear there.

0_Einstein

Monitor the output of the FTP call.  When 16#8400 is received, stop processing in the small FTP receive related FB and return to the caller no file is available (perhaps returning the 16#8400 value to the caller).

slavo_74

Hi,

I think you understood me well. I only need to do 2 operations:

1. monitor the presence of the file in the native FTP folder and retrieve it once it appears there

2. delete the file as soon as the plc has finished processing its contents

So the plc acts as a client.

Now I'm going through the document regarding LFTP that you adviced me.

So far it looks promising for me. Unfortunately I still haven't received the ordered plc, so I can't test it.

One point that worries me a bit is what happens when the folder is empty (the file is placed there periodically, can be seconds or minutes, no fixed period set) and plc tries to retrieve a file on every sweep. According to the document, error 16#8400 will occur, but what will be the further consequences (crash, freeze...)?

In the current solution InTouch monitors the folder every second and sends the figures to the plc after it has retrieved them.

 

 

Sorry for made you annoyed.

It's because, as I mentioned earlier, I'm not very familiar with Siemens plc.

My experience covers mainly Fanuc/Emerson and Mitsubishi devices with no such communication tasks, so I have more questions than answers in my mind, especially when I don't have the device yet.

Anyway, your clarification resolved my doubts and I hope it will work when I use it.

Thank you.

0_Einstein

Do you understand how PLCs work?
If not, then first learn how PLC logic "Scans"

If you already understand how PLC logic works, I am confused by what you are asking.

For the FTP block call you are intending to use:

There's stuff in front of a comm block that causes it to start acting, does nothing to start acting again once it started acting (is BUSY).

There's stuff on the outputs of a comm block where it provides status updates, like the block says it's DONE (new file arrived), or had an ERROR services the last request (no file exists, remote device offline or unavailable in some way, or configuration error).

It is easy to interrogate the Done/Error outputs because they are (typically) only true for a single PLC scan, allowing for error handling, or file(s) / contents handling.

If DONE THEN "CALL SOME FC TO HANDLE DATA";
If ERROR and (STATUS=16#8400) THEN
  # NO FILE EXISTS
  # JUST EXIT
END_IF;

slavo_74

 Hi Einstein,

I'm not sure if I follow you.

The thing is that I can't stop searching for the file since I never know when it may appear there.

0_Einstein

Monitor the output of the FTP call.  When 16#8400 is received, stop processing in the small FTP receive related FB and return to the caller no file is available (perhaps returning the 16#8400 value to the caller).

slavo_74

Hi,

I think you understood me well. I only need to do 2 operations:

1. monitor the presence of the file in the native FTP folder and retrieve it once it appears there

2. delete the file as soon as the plc has finished processing its contents

So the plc acts as a client.

Now I'm going through the document regarding LFTP that you adviced me.

So far it looks promising for me. Unfortunately I still haven't received the ordered plc, so I can't test it.

One point that worries me a bit is what happens when the folder is empty (the file is placed there periodically, can be seconds or minutes, no fixed period set) and plc tries to retrieve a file on every sweep. According to the document, error 16#8400 will occur, but what will be the further consequences (crash, freeze...)?

In the current solution InTouch monitors the folder every second and sends the figures to the plc after it has retrieved them.