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What is the xxx in PIBxxx means

Created by: LostPatrol at: 1/8/2011 7:38 PM (4 Replies)

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1/8/2011 7:38 PM	Rate (0)
LostPatrol Posts: 32 Rating: (0)	Hello All, I know what PIB is, but forgot what is the xxx follows is.. for example: move PIB1 to IB1 What does the 1 stands for? TIA!
LostPatrol Posts: 32 Rating: (0)
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1/8/2011 8:04 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 9/18/2024 Posts: 12282 Rating: (2684)	Hello LostPatrol; Your example states: Move PIB1 to IB1. Do you understand what IB1 refers to? Or MB1, QB1, or DB21.DBB1? PIB is an address for a peripferical input byte (or an analog value set at address 1 in the HWConfig editor). Normally, the PIB addresses start at the end of the Input image table of the CPU, either PIB256 or PIB512, and generally these addresses are used at word level, PIW256 or PIW512 with analog input modules. Peripherical addresses are available at any time the program needs them, which is what you want for analog modules. Bytes that belong to the inputimage table (generally digital modules) will have addresses below the limit stated, so you will address them as IB10, for example. These input values are copied to the input address table at the beginning of the CPU scan, where they remain stable for program use until the end of the scan; the resulting logic is then copied to the outpu timage table, to addrsses QB34, for example. Hope this helps, Daniel Chartier

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1/8/2011 8:17 PM	Rate (0)
LostPatrol Posts: 32 Rating: (0)	Thank you for the clarificaiton... What I wanted to do is at one point in the program I want to read the state of the input module (in this example address 1) and transfer to IB Works sort of like Immediate Input from Allen-Bradley PLC
LostPatrol Posts: 32 Rating: (0)
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1/8/2011 9:19 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 9/18/2024 Posts: 12282 Rating: (2684)	Hello LostPatrol; Peripherical addresses are always Immediate Read equivalentss, they do not go through the input image table, so they are accessed directlywhenever you read them in your program. If you read the value at PIW256, for example, if that is the address attributed to your analog channel in HWConfig, then you will see the raw value of the analog value which is either 0-27468 or ±27468 (exception, RTDs and thermociouple inputs). See the chapters on analog value representation in the S7-300 Module Data manual for more information: SIMATIC S7-300 Product Information on SIMATIC S7-300 Automation System Module Data Generally we use FC105 "SCALE" from the TI-S7 conversion library to convert this raw value to an engineering unit that we are more confortable with, percentage, gpm, cfm, etc... Hope this helps, Daniel Chartier

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1/10/2011 11:26 AM	Rate (0)
jacek d Platinum Expert Joined: 9/23/2005 Last visit: 9/18/2024 Posts: 4704 Rating: (721)	LostPatrol is completely right and for sure understands perfectly what is IB1. If you need for some reason PIB data (PIB1can bevalid address as peryphery starts at address 0 and covers all existing modules) and you wish to save it somewhere - you can save it to IB, as this is "normal" memory which can be read/written. The hack is that this location is overwritten just before OB1 scan start with actual perypherial data. Unless you switch this behaviour off in case of S7-400 processors. There are some other things - like process image partitioning, but it's a little bit off topic. Oh, BTW I would have forgotten - 1 stands for address. In case of module - the one you can find in HWConfig.
	Last edited by: jacek d at: 1/10/2011 11:32 AM Last edited by: jacek d at: 1/10/2011 11:27 AM Regards, Jacek What is confusing you is the fact that you never see a number but always its digit representation. So you end up thinking that the number is the representation. - Andrej Bauer Any claims against me - based on whatever legal reason - resulting from the use of any code and/or ideas presented on this forum shall be excluded. #StayWithUkraine
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