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Move IB to data block

Created by: Milosh at: 7/9/2013 6:06 PM (5 Replies)

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7/9/2013 6:06 PM	Rate (0)
Milosh Silver Member Joined: 8/16/2010 Last visit: 11/5/2024 Posts: 638 Rating: (12)	Hi all... How to move IBx to data block? And after that to read data block as bits... Example... Move instruction: IB5 (byte) to DigitalInputs.DI_5 (byte) Now I want to read bit 0 from DigitalInputs.DI_5 ?

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7/9/2013 6:13 PM	Rate (0)
IBN-Service Posts: 8946 Rating: (999)	Milosh Hi all... How to move IBx to data block? And after that to read data block as bits... Example... Move instruction: IB5 (byte) to DigitalInputs.DI_5 (byte) Now I want to read bit 0 from DigitalInputs.DI_5 ? L IB 5 T DBB 5 U DBX 5.0
IBN-Service Posts: 8946 Rating: (999)
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7/9/2013 6:18 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 10/26/2024 Posts: 6852 Rating: (1365)	Milosh Hi all... How to move IBx to data block? And after that to read data block as bits... Example... Move instruction: IB5 (byte) to DigitalInputs.DI_5 (byte) Now I want to read bit 0 from DigitalInputs.DI_5 ? Hello, What controller do you use? S7 1200/300/400/1500? For S7 300/400, it is not difficult to do if you knoe absolute address of the cell (byte number) you are transferring data to that.If work with symbolic addresses you will see tha absolute addresses in program editor. Best regards Hamid Hosseini
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7/9/2013 6:55 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 11/8/2024 Posts: 15388 Rating: (2443)	Milosh Hi all... How to move IBx to data block? And after that to read data block as bits... Example... Move instruction: IB5 (byte) to DigitalInputs.DI_5 (byte) Now I want to read bit 0 from DigitalInputs.DI_5 ? This is TIA Portal and it comes with a considerable amount of flexibility. If you feel more comfortable using the legacy direct bit access methods, you can certainly do as others have suggested. However, with the portal, you can use a slice of a byte (or word) by appending .x# where # is 0..7 or 0..15 (byte and word respectively). In your specific case, you already have the move command figured out, so to access the bits within your DB/tag, try this: bit 0: DigitalInputs.DI_5.x0 bit 4: DigitalInputs.DI_5.x4 bit 7: DigitalInputs.DI_5.x7 In this way, you can use a completely symbolic (versus absolute) addressing scheme and if your DB # changes, or you move things around inside your DB structure, your code will continue to work just fine after it is compiled and downloaded. The older approach may restrict your ability to do those same db # and structural changes without at least considering the things affected by those changes.
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7/9/2013 9:02 PM	Rate (0)
Milosh Silver Member Joined: 8/16/2010 Last visit: 11/5/2024 Posts: 638 Rating: (12)	Sorry i forget to mention it is s7-1200 (TIA portal) Thank you all. I will try your solutions...

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7/9/2013 9:21 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 10/26/2024 Posts: 6852 Rating: (1365)	Milosh Sorry i forget to mention it is s7-1200 (TIA portal) Thank you all. I will try your solutions... I think there is a limit of CPU's firmware for that: How in STEP 7 V11 can you access the unstructured data types bit-by-bit, byte-by-byte or word-by-word and symbolically? In the case of S7-1200 modules (as from firmware V2.0) you have the option of accessing bit-by-bit the tags of the Byte, Word and DWord data types. For this you need STEP 7 V11+SP1+Update 2 (or higher). The partitioning of a memory area (Byte or Word, for example) into a smaller memory area (Bool, for example) is also called memory slicing. Fig. 01 shows the symbolic bit, byte and word access to operands.
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