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ABSOLUTE ADDRESSING

Created by: GaJEnDrA D S at: 6/21/2013 9:53 AM (3 Replies)

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6/21/2013 9:53 AM	Rate (0)
GaJEnDrA D S Bronze Member Joined: 8/9/2011 Last visit: 11/1/2023 Posts: 324 Rating: (19)	Hi We are using those DB blocks as severall arrays of bool [0...31] mapping them to M tags to access in HMI alarms .. Even though this error appearing machine working fine, online access is also possible... But one of those bits is getting high but there is no chance of it according to the logic. I So i am guessing may be this is wat creating the problem . Thanks Attachment PLC tags.zip (475 Downloads)
	"Any intelligent fool can make things bigger, more complex. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction.":):)
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6/21/2013 3:56 PM	Rate (1)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 1/17/2025 Posts: 15541 Rating: (2465)	GaJEnDrA.D.S Hi We are using those DB blocks as severall arrays of bool [0...31] mapping them to M tags to access in HMI alarms .. Even though this error appearing machine working fine, online access is also possible... But one of those bits is getting high but there is no chance of it according to the logic. I So i am guessing may be this is wat creating the problem . Thanks In your DB structure, do you have the DB as a 32 bit bool array or as a Double word? If you change your DB to a double word, you can access the bits directly using a slice operator. For example, DB1 (let's call it DB22 to make things confusing) has the following structure: DB22[DB1] - configured for s7-300/400 compatibility, not symbolic addressing --------------- Input_Alarm0 : Dword Process_Alarm1 : Dword Output_Alarm2 : Dword User_Alarm3 : Dword' Setup_Alarm4: Dword DB1.DBD0 -> DB22.Input_Alarm0 DB1.DBX0.0 -> DB22.Input_Alarm0.x0 DB1.DBD4 -> DB22.Process_Alarm1 DB1.DBX4.0 -> DB22.Process_Alarm1.x0 DB1.DBD8 -> DB22.Output_Alarm2 DB1.DBX8.0 -> DB22.Output_Alarm2.x0 DB1.DBD12 -> DB22.User_Alarm3 DB1.DBX12.0 -> DB22.User_Alarm3.x0 DB1.DBD16 -> DB22.Setup_Alarm4 DB1.DBX16.0 -> DB22.Setup_Alarm4.x0 Now you can assign and read bits within the alarm with ease and also get rid of the absolute addressing warnings and such. Also, you may want to create a single DB, maybe name it HMI, and copy/move data to that single DB to improve efficiency of the HMI<->PC read/write, rather than reading/writing M tags - especially if the HMI is writing M tags directly. It looks like your HMI isintegrated into your portal project, so it would be fairly quick to modify. It is difficult to troubleshoot something if you havea typo in your HMI tag assignment using absolute addresses. Portal makes it so you can almost always avoid using them with a little thought. Another option is to pass your array into an FB and use the AT overlay to map it into a word or double word and then use the symbolic tag. There is a FAQ on how to do this with example project. Please update on your progress.
	science guy
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6/22/2013 12:48 PM	Rate (0)
GaJEnDrA D S Bronze Member Joined: 8/9/2011 Last visit: 11/1/2023 Posts: 324 Rating: (19)	Hi I have the DB as a 32 bit bool array . I think we can directly use M bits instead of DB itself. (I have used these DBs while migrating 200 project when we were just new to 1200 and PLC itself ) Now there is no problem with the current DB but i am facing this below problem as in the printscreen. The coil is getting high even if the preconditions that are parellel to contact of the coil are not met. Strangely 1) problem coming after the duration of more than 1 year successful run of machine 2) its happening at 1 particular machine randomly 3) not appearing any other machines Thank you Attachment 1.JPG (560 Downloads)
	Last edited by: GaJEnDrA.D.S at: 6/22/2013 6:57 PM Last edited by: GaJEnDrA.D.S at: 6/22/2013 12:53 PM Last edited by: GaJEnDrA.D.S at: 6/22/2013 12:51 PM "Any intelligent fool can make things bigger, more complex. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction.":):)
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6/26/2013 9:57 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 1/17/2025 Posts: 15541 Rating: (2465)	GaJEnDrA.D.S Hi ... The coil is getting high even if the preconditions that are parellel to contact of the coil are not met. Strangely 1) problem coming after the duration of more than 1 year successful run of machine 2) its happening at 1 particular machine randomly 3) not appearing any other machines ... Thank you On this one machine, there is (based on same machine, same logic, different behavior)a faulty or misadjusted sensor causing the coil trigger. If you add some logic to count the number of times each of the preconditions are met, and then do the same thing for when the preconditions are met forjust a very short period of time longer than just a single scan of the logic, you may discover the triggers are meeting for just long enough. I often debounce my input trigger signals to prevent this from happening. For example, if the preconditions are "system ready", and "low level on", I would add 2 TON's to force each signal to be on for at least some amount of time before latching the coil. "system ready" for say 100ms, and "low level on" for say "500ms" to keep the system from activating before it is really time and allow for natural process fluctuation. You may find there is some system degradation over the last year. Maybe a bent mounting bracket, dirty optical sensor or transmitter, or whatever. The tag descriptions are not very informative to offer better suggestions.
	Last edited by: huggy_d1 at: 6/26/2013 9:59 PM adjust for forum quote bug science guy
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