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use of --|p|-- and --|N|---

Created by: ect_09 at: 2/22/2014 7:26 PM (5 Replies)

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2/22/2014 7:26 PM	Rate (0)
ect_09 Experienced Member Joined: 1/24/2014 Last visit: 8/31/2022 Posts: 119 Rating: (1)	can anyone tell me its use of --\|p\|-- and --\|N\|--- i need its example to well understand.... am using tia portal v12

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2/22/2014 7:42 PM	Rate (0)
crazyCow Gold Member Joined: 12/4/2009 Last visit: 1/31/2023 Posts: 452 Rating: (132)	methabahmed, instructions you are asking about are positive and negative RLO edge detections. So, if a result of all logical operations before -p- instruction is true, this instruction detects positive egde and returns also true for that very cycle. After this "true" pulse this instruction remains in "false" state until next positive RLO detection. Same logic applies for -n- instruction in negative direction (negative RLO edge detection). The address you define inside this instruction is used only for storing result of logical operatin for next cycles, so you must be careful to use it only once in your program. Hope this helps, regards.
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2/22/2014 8:11 PM	Rate (0)
ect_09 Experienced Member Joined: 1/24/2014 Last visit: 8/31/2022 Posts: 119 Rating: (1)	i didnt understand. i made like this 1 2 --\| \|------\| \|--------\|P\|---------( )-- when i give input 1, it doesnt take 2 if 2 then not take input 2 please explain its working

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2/22/2014 8:49 PM	Rate (0)
crazyCow Gold Member Joined: 12/4/2009 Last visit: 1/31/2023 Posts: 452 Rating: (132)	mahtabahmed, in your example, in the first cycle when _both_ 1 and 2 are true, -p- inctruction is also true and the coil at the rung end is activated. Next cycle there is no more positive edge (it happened in the previous cycle), -p- instruction is false and coil is not activated anymore. That brings us to conclusion that this exapmle makes no sence: use rather SR bistable instead of coil: at the positive RLO edge flipflop will be set, and later you create condition to reset it. Regards.
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2/23/2014 8:23 AM	Rate (0)
ect_09 Experienced Member Joined: 1/24/2014 Last visit: 8/31/2022 Posts: 119 Rating: (1)	now i use SR block 1 2 3 --\| \|------\| \|--------\|P\|---------\|SR\|--( )-\| when 1 and 2 is activated then its set the SR, even i deactivated 1 and 2 it will remain set (3 is active ) . now what can i do that to make 3 off ?? with it. without using reset in SR
	Last edited by: mehtabahmed at: 2/23/2014 8:24 AM
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2/23/2014 10:07 AM	Rate (0)
Marcjan Platinum Member Joined: 4/22/2010 Last visit: 12/15/2022 Posts: 5697 Rating: (701)	Hello, The bit will be set untill you reset it. If you want to reset it in another network you can use the ---(R) It makes no sence tome to use the SR this way, better use ----(S) and ----(R) in that case. Regards, Marcjan
	Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
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