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dynamic Array indexing

Created by: SOble at: 1/25/2015 12:30 PM (15 Replies)

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1/25/2015 12:30 PM	Rate (0)
SOble Posts: 511 Rating: (106)	Hi guys! Imagine you got taks someting like this: You got 6 motors and under some conditions you have to start one of them. That "one of them" has to be choiced by user on HMI device. So if user enter number 5 then he wants that motor number 5 starts. All all motors have same conditions for start. Here is not the problem how to resolve this task, problem is that I want to resolve it on this way...SO here is how my data looks like. Motors.Start[1] //- motor 1 - DB4.DBX0.0 Motors.Start[2] //- motor 2 - DB4.DBX0.1 Motors.Start[3] //Start motor 3 - DB4.DBX0.2 Motors.Start[4] //- motor 4 -DB4.DBX0.3 Motors.Start[5] // '- motor 5 -DB4.DBX0.4 Motors.Start[6] //- motor 6 - DB4.DBX0.5 If user enter number 5 via HMI for example in variable n(n is INT data type) this wont work Motors.Start[n]. This is what i am looking for, how to address my array dynamicly. I have read something about pointers ,but I still dont know how to use them here. YES i know how to resolve this in SCL but that's not an option. STL and/or FBD are the options. A condition1 A condition2 S Motors.Start[n]
SOble Posts: 511 Rating: (106)
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1/25/2015 1:18 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 12/4/2025 Posts: 6885 Rating: (1368)	SOble Hi guys! Imagine you got taks someting like this: You got 6 motors and under some conditions you have to start one of them. That "one of them" has to be choiced by user on HMI device. So if user enter number 5 then he wants that motor number 5 starts. All all motors have same conditions for start. Here is not the problem how to resolve this task, problem is that I want to resolve it on this way...SO here is how my data looks like. Motors.Start[1] //- motor 1 - DB4.DBX0.0 Motors.Start[2] //- motor 2 - DB4.DBX0.1 Motors.Start[3] //Start motor 3 - DB4.DBX0.2 Motors.Start[4] //- motor 4 -DB4.DBX0.3 Motors.Start[5] // '- motor 5 -DB4.DBX0.4 Motors.Start[6] //- motor 6 - DB4.DBX0.5 If user enter number 5 via HMI for example in variable n(n is INT data type) this wont work Motors.Start[n]. This is what i am looking for, how to address my array dynamicly. I have read something about pointers ,but I still dont know how to use them here. YES i know how to resolve this in SCL but that's not an option. STL and/or FBD are the options. A condition1 A condition2 S Motors.Start[n] Hello, If you use STEP 7,you should know the structure of DB and addresses before implementing STL codes.For your case Open the targt DB--> load the index-->Check for limit range-->load P#DBX0.0-->OR Doubleword-->load to AR1-->access to memory bit. In FBD,you need comparators and manual access for all number of bits that is not a perfect solution. I hope this helps, Hamid Hosseini
	Last edited by: hdhosseini at: 1/25/2015 2:38 PM Demo Channel on Youtube
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1/25/2015 2:25 PM	Rate (0)
SOble Posts: 511 Rating: (106)	Yes I'm using step 7 and s7-300 plc I know there is something about pointers but still dont know how to implement that in this case. How to loop this array with pointers, and how to SET specific bit in array on the index choiced by HMI
SOble Posts: 511 Rating: (106)
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1/25/2015 2:45 PM	Rate (1)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 12/4/2025 Posts: 6885 Rating: (1368)	SOble Yes I'm using step 7 and s7-300 plc I know there is something about pointers but still dont know how to implement that in this case. How to loop this array with pointers, and how to SET specific bit in array on the index choiced by HMI You work should be roughly like this: OPN DB 3 ///////////////////////////////// //Checks L MW 100 L 7 >I // JC aus1 ///////////////////////////////// //pointer L MW 100 L P#DBX 0.0 OD LAR1 SET = [AR1,P#0.0] //rest of codes aus1: NOP 0 For pointer in STL with loops check (THIS).
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1/25/2015 9:31 PM	Rate (0)
SOble Posts: 511 Rating: (106)	Hey! I think this is what i am looking for ,but can you explain me why did u use order OD //and also why did u used double word and on the end whats in the [] [DB3.DBX5.0] or [DB3.DBX0.5] in a case that inside MW100 is a value =5
SOble Posts: 511 Rating: (106)	Last edited by: SOble at: 1/25/2015 9:32 PM Last edited by: SOble at: 1/25/2015 9:31 PM
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1/26/2015 7:17 AM	Rate (2)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 12/4/2025 Posts: 6885 Rating: (1368)	SOble Hey! I think this is what i am looking for ,but can you explain me why did u use order OD //and also why did u used double word and on the end whats in the [] [DB3.DBX5.0] or [DB3.DBX0.5] in a case that inside MW100 is a value =5 Hello again, Short answers to your questions: OD because to combine the bit position with structure of previously loaded pointer. DoubleWord because of a pointer structure If MW100:=5 then in "[AR1,P#0.0]", you point to DB3.DBX0.5. Also check this: variable addressing (with an pointer) I hope this helps, Hamid Hosseini
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1/26/2015 10:19 PM	Rate (0)
SOble Posts: 511 Rating: (106)	Yes it does help, what in a case I need to set Db3.DBX5.0? would this work L MW 100 //inside is value :=5 L P#DBB 0.0 OD LAR1 SET = [AR1,P#0.0]
SOble Posts: 511 Rating: (106)
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1/26/2015 10:37 PM	Rate (0)
SOble Posts: 511 Rating: (106)	Also one more question but maybe is out of topic: is it possible to set whole array to some value for example 0 I know it is in some higher programming language. for example array Motors.Motor[1..5] something like : Motors.Motor[1..5]:={0} or i have to make loop or literally R Motors.Motor[1] R Motors.Motor[2] R Motors.Motor[3] R Motors.Motor[4] R Motors.Motor[5]
SOble Posts: 511 Rating: (106)	Last edited by: SOble at: 1/26/2015 10:38 PM
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1/27/2015 5:44 AM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 12/4/2025 Posts: 6885 Rating: (1368)	SOble Yes it does help, what in a case I need to set Db3.DBX5.0? would this work L MW 100 //inside is value :=5 L P#DBB 0.0 OD LAR1 SET = [AR1,P#0.0] You need an extra Shift Doubleword to lift: OPN DB 3 L MW 100 //inside is value :=5 SLD 3 /// byte position L P#DBX 0.0 OD LAR1 SET = [AR1,P#0.0]
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1/27/2015 5:58 AM	Rate (1)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 12/4/2025 Posts: 6885 Rating: (1368)	SOble Also one more question but maybe is out of topic: is it possible to set whole array to some value for example 0 I know it is in some higher programming language. for example array Motors.Motor[1..5] something like : Motors.Motor[1..5]:={0} or i have to make loop or literally R Motors.Motor[1] R Motors.Motor[2] R Motors.Motor[3] R Motors.Motor[4] R Motors.Motor[5] Test this example, you can change the number of bits in array.I know it is much easier to manipulate Double words,It saves your CPU execution time a bit( to reduce loop number).In this case your , number of bits should be multiplication of 32. OPN DB 3 L 60 // number of bits in arrray lp: T #zaehler L P#DBX 0.0 OD LAR1 CLR // SET = [AR1,P#0.0] L #zaehler LOOP lp
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