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How to count higher than 6

Created by: dobber at: 1/15/2007 4:41 PM (4 Replies)

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1/15/2007 4:41 PM	Rate (0)
dobber Posts: 1 Rating: (0)	Hi, first of all sorry if this is in the wrong section. Right, my dilema is that i need to create approx 80 counter functions counting from 0-65535 or higher. I know you can use the SFB2 CTUD found in; Standard librarys, System function blocks. This is addressed to a DB and you can output the number to a DW. If i us ehtis method i will run out of DW. I remember seeing a Siemens engineer showing me how to make your own type of counter that could count to over 2,147,483,647 which is a bit excessive but kind of what i need. This counter needs to be able to display an actual number which will be sent via a CP343-1 unit to a server which will display counter figures. Is there any other way i can get a count out. I'm open to any idea's or suggestions, all help is most welcome :) Many thanks Duncan PS this is going to go on a S7-315-2 DP
dobber Posts: 1 Rating: (0)	Last edited by: dobber at: 1/15/2007 4:43 PM
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1/16/2007 11:11 AM	Rate (0)
Aret Posts: 2348 Rating: (264)	First idea = use counter cascade. I mean when least significant counter reaches maximum value set it to 0 and increment other counter 2) same idea but with your own variables. - you can get long variable for counting till 999 999 999. With 2 such variables you can count till 10^18-1 - i guess i would be enough. I didn't quite understand your memory problems 80 timers * 2DWORDs = 640 bytes of memory - not too big for 315 CPU. Maybe you can just increase your MMC size? If you are planning to pass data to WinCC you still have to all 640 bytes. 3) Use "long math" - method used in PC to describe very big numbers - they are simply stored as strings. But you have to write your own +-/ in this case. For implementing what i gave mentioned in 1),2) you have to write your own FC/FB (guess FB is preferable - it can store your counters as STAT variables). There you write smth like IF (Input_Comand_CU) THEN if (least_counter = 999 999 999) then leasts_counter := 0; mosts_counter := mosts_counter; else leasts_counter := leasts_counter +1; end_if; END_IF; Accordinally you can write for CD command. So if you would like to now current value you can use this (supose DB1 is instance of your FB): DB1.mosts_counter1 000 000 000+DB1.leasts_counter
Aret Posts: 2348 Rating: (264)
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1/16/2007 1:57 PM	Rate (3)
Jeebs Posts: 218 Rating: (28)	Hey, So you want counters that count over 65k, but not over 2,147,483,647. Attached you should find a FC that counts over 65k. This will give you an idea of how it can be done. Where as I have used MD in the example you should use DD's. Hopes this helps. Jeebs Attachment Counter.zip (674 Downloads)
Jeebs Posts: 218 Rating: (28)
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1/16/2007 11:09 PM	Rate (0)
Late Platinum Expert Joined: 1/7/2006 Last visit: 11/17/2023 Posts: 2705 Rating: (318)	Dear Jeebs, Thx for the block, it is working and thats what the users want [8)]
	I hope that the answer will help, if you have still questions, don't hesitate to ask me. All the best, Late Never say never, think in solutions, not in trouble......
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1/17/2007 1:55 AM	Rate (0)
Tennessee Chris Posts: 4 Rating: (0)	I'm just a beginner, but the way I do it is use a "ADD_DI" add double interger. you put an use db1.dbd0 for both " in 1" and "out". and a db1.dbd4 (with a L#1) as "in2". this will take the contents of db1.dbd0 , add 1 to it and store it back in db1.dbd0. use the same db over and over until filled up. this same db address can also be referanced to an OP for a visual reading. to reset just use a "MOVE" and move an address with 0 back in the db address. if you need an example in ladder let me know and i'll get one at work that i can email you. sorry but i don't do STL.
Tennessee Chris Posts: 4 Rating: (0)
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