Simatic SFB14 (GET)

[marcius]

I need to read some data from remote S7-400 (CPU414-1) PLC.
Local PLC is S7-400H (CPU412-3H). Comms is established theough ethernet CP 443-1.

If i do like this communication is running and I can read data from remote PLC without errors except that sometimes i get status code 25 (Communication has started. The job is being processed)

A M 0.7
S #PLC_COM.GET_REQ

CALL "GET" , "GET_Instance_DB"
REQ :=#PLC_COM.GET_REQ
ID :=#PLC_COM.ID
NDR :=#PLC_COM.GET_NDR
ERROR :=#PLC_COM.GET_ERROR
STATUS:=#PLC_COM.GET_STATUS
ADDR_1:=P#DB41.DBX2.0 BYTE 2
ADDR_2:=P#DB201.DBX0.0 BYTE 26
ADDR_3:=
ADDR_4:=
RD_1 :=P#DB401.DBX0.0 BYTE 2
RD_2 :=P#DB401.DBX6.0 BYTE 26
RD_3 :=
RD_4 :=

ON #PLC_COM.GET_NDR
O #PLC_COM.GET_ERROR
R #PLC_COM.GET_REQ

I tried to do like this:

AN #PLC_COM.GET_REQ
S #PLC_COM.GET_REQ

CALL "GET" , "GET_Instance_DB"
REQ :=#PLC_COM.GET_REQ
ID :=#PLC_COM.ID
NDR :=#PLC_COM.GET_NDR
ERROR :=#PLC_COM.GET_ERROR
STATUS:=#PLC_COM.GET_STATUS
ADDR_1:=P#DB41.DBX2.0 BYTE 2
ADDR_2:=P#DB201.DBX0.0 BYTE 26
ADDR_3:=
ADDR_4:=
RD_1 :=P#DB401.DBX0.0 BYTE 2
RD_2 :=P#DB401.DBX6.0 BYTE 26
RD_3 :=
RD_4 :=

O #PLC_COM.GET_NDR
O #PLC_COM.GET_ERROR
R #PLC_COM.GET_REQ

This way GET request processed only once i don't understand why because error and status outputs of GET block stays 0, so I think GET request processed succesfully and NDR output should be set to 1(NDR: 0 - Job not started or still active, 1 - Job successfully completed.), but it never goes 1 it stays 0.

 

[PeterMalt]

First you could try to read every 5 seconds for test, if it run without problem you lower the the time.

 

[marcius]

Thanks for reply, but I think you misunderstood me. I fine with status code 25 I know why it's showing up. It's because I start request while the previous job is still running.

My question really is why NDR never goes 1. According to manual NDR=1 when job completed successfully.
In my case NDR always stays 0 even though ERROR and STATUS remain 0.

 

[krk]

Give this a try...

CALL  "GET" , "GET_Instance_DB"
       REQ   :=#PLC_COM.GET_REQ
       ID    :=#PLC_COM.ID
       NDR   :=#PLC_COM.GET_NDR
       ERROR :=#PLC_COM.GET_ERROR
       STATUS:=#PLC_COM.GET_STATUS
       ADDR_1:=P#DB41.DBX2.0 BYTE 2
       ADDR_2:=P#DB201.DBX0.0 BYTE 26
       ADDR_3:=
       ADDR_4:=
       RD_1  :=P#DB401.DBX0.0 BYTE 2
       RD_2  :=P#DB401.DBX6.0 BYTE 26
       RD_3  :=
       RD_4  :=

      A     M      0.7
      S     #PLC_COM.GET_REQ

      O    #PLC_COM.GET_NDR
      O     #PLC_COM.GET_ERROR
      R     #PLC_COM.GET_REQ

Make sure that M0.7 is a one-shot signal.

 

[marcius]

I'll give it a try.
M0.7 is Clock memory bit

 

[krk]

M0.7 is Clock memory bit

Make a rising or falling edge of it.


I use the 500mS clock memory bit for this and it works fine.

Also, don't forget to clear any outstanding GET request on PLC start up (reset #PLC_COM.GET_REQ on first scan).

 

[marcius]

Thank you, krk I modified program as you pointed out.
Now my GET block works good I still sometimes get status code 25, but that's not really a program.

Now I have problem with PUT block I get ERROR and STATUS 4 - "Errors in the send area pointers SD_i involving the data length or the data type."

//CALL "PUT" , "PUT_Instance_DB"
REQ :=#PLC_COM.PUT_REQ
ID :=#PLC_COM.ID
DONE :=#PLC_COM.PUT_DONE
ERROR :=#PLC_COM.PUT_ERROR
STATUS:=#PLC_COM.PUT_STATUS
ADDR_1:=P#DB201.DBX22.0 BYTE 4
ADDR_2:=
ADDR_3:=
ADDR_4:=
SD_1 :="PUT_DB".IU_SetPoint
SD_2 :=
SD_3 :=
SD_4 :=

"PUT_DB".IU_SetPoint (REAL) -> P#DB402.DBX0.0 BYTE 4
I am 100% sure address (P#DB201.DBX22.0 BYTE 4) in remote PLC is correct.

 

[krk]

I'll take it as given that you have loaded the DB "PUT_DB" to your PLC?

For SD_1, have you tried substituting P#DB402.DBX0.0 BYTE 4 for the symbolic "PUT_DB".IU_SetPoint?

 

[marcius]

Yes DB is loaded.
For SD_1 I enter absolute address and it's automatically replaced with symbolic.

 

[krk]

Can you post the relevant section of your code (without the hardware config)?

 

[marcius]

Yes i did.