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Counters in Step7 Basic

Created by: spencer at: 9/16/2010 4:46 PM (6 Replies)

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9/16/2010 4:46 PM	Rate (0)
spencer Posts: 8 Rating: (0)	Pegaia Hi, I and a college, Mr. Paiva, mount a little sample program that send RS232 ASCII telegrams to a PC with HyperTerminal from a S7-1200. Follow there is the project, a picture with the HyperTerminal adjusts and the looks like in this software.We use the follow RS 232 cable:2-3; 3-2; 4-6; 6-4; 7-8; 8-7; 5-5 Attachment:serial.zip (154 Downloads) Pegaia Hi, as second example, here is a project that recive data from HyperTerminal Attachment:HyperTerminalRecive_RS232.zip (119 Downloads) hello Denilson ... I write to you from South Africa ... Johannesburg ... I have found and downloaded your program - for ... serial.zip .... and also ... HyperTerminalReceive_RS232 ... I am surprised at how simple it really is.... I am sure though that you need to use the other faculties of the PtP system, for serial..???? yes..??? - or NO..??? Unfortunately - I do not have the serial port for my 1212C - S7-1200..... but nevertheless - it is good to try to learn something newer everyday...!!!!!! [schnippschnapp] 2) - I would like to make a project - where I have three (3) counters, or more- (UP Count) - so they are daisy chained.... I have that worked out I think... so that units counter is ...1 .... and then 10's counter is to 10 .... and then hundreds counter is to 100's ....etc.. (the wish - is to count some pulses from a "power unit" - that gives 1 pulse for every 100 watt power used.. then I wish to count these pulses - and then SEND them from the CV value for the counters - on the serial port ...to my PC = which has a program - to write RS232 incoming values to a file...).. so I need to read CV(1) - and send data ... switch to CV(10) and send data value... and then switch to CV(100)... read data - and send to PC... on serial port... (of course - I have only three counters - but the wish is to have maybe 1's...10's...100's...1000's ..... 10000's - so that I can count like in power meter mode...hmmm.. How do I write / draw the LAD file, so that I can do this..... please..??? Excuse me for wanting to fly before I can even crawl... but that is me..!!!!... With this method - I can keep software overheads cheap.... and can save the data - in simple text format - in file on the PC, for present performance - and history performance of said energy pattern / usage levels...hmmm.. Denilson - I thank you very much - you are an inspiration.... to me... My Kindest Regards Spencer Sabatta Johannesburg South Africa.. Splitted from Sample program S7-1200 RS 232 ASCII HypterTerminal comunications.
spencer Posts: 8 Rating: (0)	Last edited by: O_Moderator at: 9/20/2010 12:31 PM Last edited by: O_Moderator at: 9/20/2010 12:28 PM new subject after splitting
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9/16/2010 5:52 PM	Rate (0)
Denilson Pegaia Platinum Expert Joined: 9/23/2005 Last visit: 9/13/2024 Posts: 4347 Rating: (1446)	Hello Spenser, The PtP applications, generally are simple, however there is many resources available. Here your answer: [schnippschnapp] 2) The question about your application, is a question of string handling and not of PtP communication. Maybe would better if you post it in a separate tread. However a quick explanation. You can use S_Convert to convert a number on a string. There others string functions that you can use to merge strings, like len, concat, left, right, mid, delete, insert, replace, find, etc. in Extended instructions, stirng+char path.
	Last edited by: O_Moderator at: 9/20/2010 12:29 PM Last edited by: Pegaia at: 9/16/2010 5:52 PM Denilson Pegaia Siemens Industry Sector Technical Support
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9/20/2010 4:46 PM	Rate (0)
spencer Posts: 8 Rating: (0)	Hello - Denilson... well I have made up a ladder logic diagram, using CTU - upcounters. The CV value for each counter, is now...%MW0, then %MW2....%MW4.....%MW6....%MW10 ....okay... How do I get these registers organized to become something, that I can store in a data-block, or even read-off with a RS232 port, to the outside PC...hmmm...???...please...??? The idea, or the wish, is that at a certain time - they are all at some value....okay... then I need to "freeze time" them....so that I can read them off.!!!.. they would then form the basis of a number, to be stored in a PC... Denilson - I thought of using the MOVE_BLK system... so that the IN ...array...is formed from %MW0,%MW2,%MW4...etc etc... how do I do this please...???.. Could you help me here please.???.... Thanking you kindly... Spencer
spencer Posts: 8 Rating: (0)
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9/20/2010 7:24 PM	Rate (0)
Denilson Pegaia Platinum Expert Joined: 9/23/2005 Last visit: 9/13/2024 Posts: 4347 Rating: (1446)	Hi, Unhappily, the MOVE_BLK just move variables of the type “array [x..y] of elementary data type”. If the source and destination are array of the same data type, that’s ok. Else, you will need to move each Byte (or workd or dword) individually, by the absolute addressing.
	Denilson Pegaia Siemens Industry Sector Technical Support
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10/8/2010 4:41 PM	Rate (0)
spencer Posts: 8 Rating: (0)	Hello Denilson - please can you tell me whether - I am allowed to have more than one SEND_PTP block in a program structure...??? It is maybe the only way that I can get my data printed... I am really battling with this task = and it seems to me that there is NO ONE - who can do what I want to do... - or maybe explain it clearly enough - for me to understand... I have constructed - some program - and now am just fiddling around - until something works...hmmm I cannot afford the training exercises that Siemens - in SA - offer... they are far far too expensive....hmmm I would rather spend that money on buying new hardware - etc etc.... I think that the S7-1200 is a very nice little PLC - and well - I am really battling...hmmm Thanks Denilson... Spencer P.S. - do you get my emails - I send to your Brazil Office...????
spencer Posts: 8 Rating: (0)
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10/8/2010 5:02 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 9/16/2024 Posts: 15188 Rating: (2417)	Multiple SEND_PTP are allowed, but not needed for a well designed system, and very likely will cause problems if multiple SEND_PTP become active at the same time. There is no reset input to the SEND_PTP so if it tries to send and never completes are generates an error, it just hangs, preventing any further commands from being send. A power cycle or PLC stop/start is required to reset the serial comm module and the SEND_PTP command. Sending data via SEND_PTP is fairly simple. (for RS485)If you have multiple things to send, be sure to invoke a delay timer in your software to prevent back-to-back sending. Otherwise you won't receive responses - assuming you are expecting some kind of ACKnowledge back from the device you are sending to. Ensuring your data is properlyreceived is much more involved. I created a fairly robust system for sending data to multiple devices in a semi-asynchronous mode. No message queue or FIFO stack was required. Works great, simple to understand, but has a lot of logic, more than fits on a single screen snapshot. There is an FAQ that talks about using STRING buffers for SEND_PTP instructions. I would urge you to look at that before you get your serial comm module.
	science guy
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10/11/2010 11:26 AM	Rate (0)
spencer Posts: 8 Rating: (0)	Hello Denilson - thanks for the very encouraging answers..... Maybe I am too stupid to understand - what you are saying - about not doing things on the serial port.... but I have a small project - that I am sure will work - eventually - and be of use to a lot of folks...hmmm. Denilson - do you mind to send me that "project" - of yours involving that project - so that I can read through - what you did.... please..???.. I need it so that I can try to work through your I/O logic, so that it can be of some use to me - to get my thinking sorted out.... I would really appreciate that, if at all possible....hmmm... Denilson - I thank you very much for your time... to answer through all my stupid silly questions... of which I am quite sure - you very advanced folks - are all very tired of....hmmm.. My Kindest regards Spencer..
spencer Posts: 8 Rating: (0)
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