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NCk variable read in PLC.

Created by: vitmon at: 7/27/2006 3:48 PM (9 Replies)

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7/27/2006 3:48 PM	Rate (0)
vitmon Member Joined: 7/25/2006 Last visit: 11/6/2014 Posts: 1 Rating: (0)	Hello, I need to read NCK-variable $VA_IM (840D) in PLC. Tried step by step from manual - does not work, Anyone can help? Thanks a lot.
	Last edited by: vitmon at: 7/27/2006 3:50 PM
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7/28/2006 3:23 PM	Rate (0)
shanny Posts: 44 Rating: (0)	Hi, I assume you are using NCVAR Selector to set up the internal address and parameters that the function block FB2 requires. Even Siemens engineers run away in terror at having to use NCVAR Selector. All that ncvar does is to create a data block that has to be imported into S7. This data block holds the information that FB2 (GET) will use to retrieve the axis position you have requested. The system does work but it is not clear how to get the correct drive. Are you getting any information back at all ?. Try changing the unit number. If you can wait till next week and are desperate I can post a working DB and FC to use as a template. Shanny
shanny Posts: 44 Rating: (0)
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8/30/2006 3:45 PM	Rate (0)
electro-gene Posts: 2 Rating: (0)	You could also write your $AA_ into a $ANA_OUT and retrieve the value on the other side in DB10. You need to parametrize the $ANA_OUT such as free (not used by CNC) and not connected to hardware but redirected to the DB. Be aware that the resolution is the same. it's depends what precision you need on your PLC-side application. If you want to trig an action on the process, it should be more useful to use a SYNC FUNC, directly inside the CNC part-program
electro-gene Posts: 2 Rating: (0)
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12/10/2008 1:43 PM	Rate (0)
jagan_tt Posts: 3 Rating: (0)	DearShanny , Could you please provide me the working sample DB for reading the axis positions.My email id is jagan_tt@yahoo.co.in. I am really having a difficult time trying to get this NCVAR working. Jagan_tt
jagan_tt Posts: 3 Rating: (0)
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1/28/2009 9:50 PM	Rate (0)
fas Posts: 4 Rating: (0)	Is the DB121 generated into step7 project without mistake? Now I have no time but send me your email.
fas Posts: 4 Rating: (0)
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2/2/2009 6:17 AM	Rate (0)
jagan_tt Posts: 3 Rating: (0)	Thanks for your comment sir. I have made a mistakewhile generatingDB121. Now it is working fine. Thankyou sir
jagan_tt Posts: 3 Rating: (0)
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11/11/2016 1:53 AM	Rate (0)
AutoGen_680666 Posts: 4 Rating: (0)	Hello! I need to read this variable "block" from the NC to transfer to the PLC but I am not very clear how the DB is constructed with the String and cone can be addressed. In the explanation it expounds the following but I do not have it completely clear. If you can give me an example ... Thank you very much to all!!!! To display the currently active part programm, NCK supplies 3 ascii-blocks of the part programm in one single variable job (last, current and next block). That means the variable 'block' consists of a maximum of 3 lines: Line index 1: string of the last block Line index 2: string of the current block Line index 3: string of the next block To gain consistent information, all 3 array elements must be processed in one variable request. This is why the maximum string length of each array element is limited to 66 characters. Attachment Sin título.png (627 Downloads)
AutoGen_680666 Posts: 4 Rating: (0)	Last edited by: AutoGen_680666 at: 11/11/2016 2:02:16 AM
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11/14/2016 10:17 PM	Rate (0)
AutoGen_680666 Posts: 4 Rating: (0)	Well, I'm self-authoring as a solved subject.In the manual I did not understand very well in English or translating it into Spanish as structuring the DB after using the function FB2 Get to deposit the data of the CN when we want to visualize the previous block of current of the programda of the CN that is going on when working,To have them consistently the strin length must be max 66 characters It turns out that after returning and returning to test and to arrive the manual and the aid when you generate the source with the NCVAR Editor asks you which line you want to use, clear in the aid says 1 = last 2 = current 3 = next, therefore generating the threeData one with each selection of the line generates a source with the three DB structures to insert into my project.Then I create the destination DB to deposit the data 3 string of 66 characters each and then the function FB2 Get is already used where I tell the address or query address data and the destination Rd from where I deposit the data. I must imperatively open a table of variebles to see something and there I see that the data is deposited correctly and with all its characters!
AutoGen_680666 Posts: 4 Rating: (0)
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1/30/2019 8:33 AM	Rate (0)
AKASH SINGH Advanced Member Joined: 4/8/2014 Last visit: 11/1/2024 Posts: 8 Rating: (0)	can any one share the procedure of nck variable read in plc

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1/30/2019 7:27 PM	Rate (1)
nulizhang Platinum Expert Joined: 10/17/2007 Last visit: 1/17/2025 Posts: 4155 Rating: (363)	I don't think that is easy to share the procedure. But I can give your basic steps, then you need to read Siemens manual ( I will tell you the manual name). and you need Software --SIMATIC manager (STEP7) + 840D Tool box ( basic PLC program+ NC VAR selector. #1--you need know PLC prgramming by STEP7 and 840D basic PLC program, you have PC/PG with NC var selector , use it to select NC variable and generate to PLC S7 Data block. #2--You use FB2 or FB3 (read and write ) to transfer from NC to PLC or from PLC to NC, the manual you need to read "SINUMERIK 840D, FUNCTION description part 1 Basic , (P3--PLC basic program, check FB2 and FB3) AKASH SINGH can any one share the procedure of nck variable read in plc
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