How to create SYSTEM FUNCTION BLOCKS (SFBs) in Siemens STEP7 Professional!

welcome back everybody and today we're going to be having a look at Siemens system function blocks or as they like to call them SF B's now before we actually get into the video what I think you could do is like the video comment below and then if you're watching this on youtube hit the subscribe button and already care what you hit it with just hit it anyways let's get back to this video so last week we had a look at Siemens counters inside a step 7 Professional and we really highlighted the reasons why we don't use those counters inside of our programs when using step 7 professional and the reason for that was because they didn't really work like Siemens counters should we showed you how they worked inside a TI a portal and how they work in other PLC's however when it comes to step 7 they work slightly different now seems does have another set of counters inside of step 7 and those are inside of what it calls the SFA's the system function blocks these actual function blocks that have been created by Siemens and then stored onto the CPU of the PLC meaning that when we use them we don't have to actually download them to the PLC but already on that PLC just like any other function block inside of step 7 or ti a port that we use we must always assign an instance data block to that we're gonna be showing you how we can actually use them inside of programs how to set them up how to create the instance data blocks and then how to get them working inside of a PLC program let's get started so if you look at my project at the moment you'll already see OB one available and then you'll see six other blocks and these other blocks will be SF Bay's and you'll notice on these blocks as little power blocks this is because being created by Siemens and these cannot be altered by us we can't go inside of these blocks and start opening the code they are fixed and like I say they're already on that CPU now if I just try to open up an sfb this block is protected and you can't see anything there and that's the same with all the other SF B's now what I'm gonna do here is I'm just gonna do these SFPs from this program and we're gonna start afresh just say yes to that and we're gonna open up obi-wan to start with now inside of will be one we've got a blank program so far and if you look on the left hand side where your instructions are there is your counter folder and we also have our timer full - just below that with the Siemens 10 timers available now just below of that you'll see some other folders labeled function blocks functions SF B's and SF C's and if we just open these blocks you'll notice that there's nothing inside of them when we start to create these SFPs and SF C's or just function blocks and functions inside of our programs we actually start to add it to the ladder that's when you'll see these folders start to be populated with the blocks that we're using to the basic user of steps unprofessional a lot of people don't even know that these system function blocks exist to locate where these system function blocks are all we have to do is open up our libraries folder open up standard library and then inside of there about midway through is your system function blocks folder now if we over know system function blocks this is where all of the system function blocks are located yeah you'll see the first six are your counters and your timers and these counters and timers are very similar to water inside of Ti a portal at the moment if I just open up TI a portal here and then we go to our time operations there are the timers that Siemens have created inside of step seven excluding the t o n R and if we open up the counter folder there are our counters now if we just go back to this you'll notice next to these names here CTU CDD CTU D etcetera is ie C this is part of the programming standard IEC 631 - three these are IEC counters and IEC timers what this means is we actually create these blocks inside of seaman steps unprofessional we can then convert that program to another PLC and it will convert over with those timers as they are designed to the IEC standard the other counters and timers are Siemens using these folders if we use those inside of our programs and we try to convert that to another PLC program it wouldn't convert correctly because those timers and counters might not be available in another programmer however these see to you CTD and CTU d & TPT o N and tof blocks or these are IEC blocks and these are the blocks were gonna have a look at you'll notice that there's quite a few other blocks as well we're not gonna get too involved with these other blocks right now is there a bit more advanced all we're gonna be able to look at is the most commonly used ones our counters and our timers now these work just like they do inside the TI a portal so I'm not gonna go too much into the actual functionality we're just gonna start adding with my program set it up and then get them running so the first thing we're gonna have a look at is our C to you we looked at counters last week and why we don't use them well let's have a look at how the CTU works and if it works just like it does in CIA portal so I'm just going to drive my seat to you to the PLC program and you'll notice when I first dragged that block over there's question marks at the top of the block this question mark isn't referring to giving it the count and number or giving it a timer number or anything like that this is referring to a date the block whenever you create a function block inside of Siemens you must assign a date of lock to it this is its instance data block and what that instance data block does is when the PLC executes the code for the laugh count are there it stores the results from that counter into woods data block and then it can refer to that later on in the program we can also access that date block and use it in the program as well now let's assign that data block to db1 and then select enter and you'll notice when we select enter there it pops up with another dialogue box and that bear States this instance data block db1 does not exist do you want the generator I'm gonna say yes and what that does it allows the scene stepson professional programmer to create that data block if I just save this and then close obi-wan down you'll now notice inside of somatic manager there is my s FB 0 which is the counter up function block and there is my DB 1 if I change the view to a detailed view you can actually see the name of the function block labeled as C to you that there is our counter or function block so if you ever do see these SF B's and you're not sure what it's referring to just click the details window pane and that there will change over the view to its detailed view and there you can see the actual symbolic name being a CTU I'm just gonna go back to small icons as that's why I prefer now if we open up OB 1 again you'll notice on this function block you've got several inputs just like our TI a portal program you've got the seed to you here you've got the Cu which we're going to tie to just an EM bit and we'll use em 0.0 you've got the R which is your reset and we'll tie that to M 0 dot 1 you got the PV which will tie to 6 and you got your Q which will tie to Q 4.0 the CV isn't needed we don't have to have that CV there that's just your current count value what we could do is we could store that inside of a memory word or whatever and then use that on an itch my or a SCADA system so that the operator could see how much this counter is already counted if it's needed one what I do now is I'm just gonna save my work and then I'm gonna download this to the PLC now if you remember how count has worked previously inside a step seven as soon as we triggered the count of signal it would begin counting straightaway and the output would turn on straightaway that's not what we want what we want is when this count up signal has been triggered six times I want the output queue 4.0 to turn on hit the glasses go online and you'll notice when I went online there it's currently in stop mode and if we look at my plc it's currently in stop mode and the system fault light is on now there's a reason for this and the reason is this data block hasn't been loaded to the PLC the function blocks already in the PLC for the data block isn't I can't just download Ruby one and not download the data block as the PLC is now saying well where's this data block I need to store this information in that day at a book so what I'm gonna do is I'm now gonna come offline and I'm gonna close down Obi one and I'm gonna do a full download will download this data block here to do that just click the download icon say yes to all load the system did yes to that restart the PLC and now when I go into Obi one and I go to goggles it's now live and if we look at my PLC behind me the system fault LED is no longer on and we are in run mode remember when when we create a function block it asks you to create an instance data block alongside it that data block needs to be downloaded so let's have a look at this what I'm gonna do here is I'm just gonna right-click M zero zero modifying it to one and the count accounts one I'm then going to zero my counter trigger it again and it will count to zero it trigger it three for five six and when we hit six inside of this counter my output q 4.0 turns on and that's it that's your counter now working like a count a dozen any other plc now to reset this one is going to reset my see you back to zero and then trigger the reset and when we do that my counter goes back to zero ready to start again now if I just come off line on it'll be one and close down ooby one now if I open up my DB one and just select it yes to that you'll actually see my DB with the input and the output as well as a stat now this is all to do with the function block declarations internal declarations inside of function blocks and we actually cover that on our siemens programming series online so I'm not going to go too much into that but if we look here we can see there's our see you there's our art there's my PV there's the Q C V and there's my internal register now what I'm going to do is I'm just going to open up obi-wan minimize this a little bit open up my data block minimize that a little bit as well and what I'm gonna do here is just go back online and now if I modify this to one and I go online in my goggles here you can actually see there's my input see you the count up signal on my reset is currently off my PV is currently set to six which it is the output is currently off which it is and if you look at the CV which we haven't assigned it's currently one if I then just 0m 0.0 you can actually see it then turn to false trigger it again and you'll now see the counter counter to zero it turn it on again zero it turn it back on zero it turn it back on zero it and then finally turn it back on once more you'll see it hit six and now the output has turned the true you'll notice the stat operating as well whenever I trigger to see you that there is internal to the function block we don't see it on the actual function block here it's inside of there inside the actual code you'll see row that and then trigger my reset to send the whole block back to zero and that there is ultimately what an SF B is it's a block that has been created by Siemens to do a certain task it's then locked up so we can't modify it we can then add that to the PLC program and then assign it to a date of lock when the PLC executed that block it then stores the information in that date a block and then pulls back from that data block on the next scan for the next operation now what I want to do is we're just gonna close down db1 expander b1 a little bit more come offline and I'm going to create another Network and I'm gonna add in another SFB zero another counter up again it'll ask me for another data block now I can't assign this to DB one because we're already using that in the plc that would be essentially duplication what I'm gonna do here is I'm going to assign it to db2 and again it'll ask me do you want to create it but I'll just say yes to that and what I'll do here is I'll use M 10.0 m 10.1 and again I'll count to six I'll use the next output available and I'll just leave my CV blank I'll save that again I can't download from would be one because I've now created another data block what I must do is close will be one download it from somatic manager and download all of the blocks say yes to that say yes to that say yes to that and then go back to run mode now if I open up o b1 and just minimize that block so we can see both networks I can then go online here and then if I open up db1 and say yes to that I can then trigger my db1 and if I just go online you'll see the live of value of that data block and I'll just zero that but if I trigger my second count there the one that's register db2 and I say modify to one you'll notice nothing happens inside of this data block this is actually activating inside of data block - so it keeps it completely separate so if I just close this down here and open up db2 now and say yes to that and then I open up my Ruby one again and then go back online with db2 you can then see the current state of that block so again as I add function blocks to the program you assigned data blocks to it the PLC and stores that data from that function block inside of its relevant data block and then we can access that later on if we wanted to I'm just gonna close that down so that there is an SFB inside of the PLC in that base your counter up let's just have a look at another sfb and we're gonna have a look at a timer this time if I open up standard libraries and then I go to system function blocks and then I open up to you when what I'm gonna do again is assign another day block though I can't assign DB one because currently it's being used for my counter even though I've deleted it but I can assign bb3 say yes to that give the input to this M 0.0 set the time value 2 T hash 10s and then set the output to cube 4.0 you'll notice I'm no longer using the S 5 T hash I'm using the T hash identifier and this is very similar to TI a portal in TI important you don't use s5t hash like you would do on these timers over here you use T hash 10s and again this is because this is an IEC block and IEC block is meant to be able to be used in all PLC's if you start using s 5 which refers to the Siemens S 5 PLC then using it inside the Mitsubishi wouldn't make much sense so we use T hash 10s now what I'm gonna do is I'm gonna save my work Clues will be one down I could then effectively delete DB 1 and db2 and s FB 0 for wanted to it's not being used my program but I'm just going to leave them may download that to the PLC you say yes to that say yes to that yes to that and yes to that yes to that and then yes to that and then yes to that a lot of warnings a lot of warnings open up will be one go online and then what we want to do is open up our DB 3 block this time see yes minimize this just shrink down our ubi one go online with this data block and here are my actual values and what I'm gonna do is I'm gonna trigger M 0.1 and then you can watch your steamer running and off it goes one second two second three second four seconds after 10 seconds Q 4.0 will turn on and there we go Q 4.0 is now on and then that output there is all inside of the program as well close that down and then expand that this year like I say our sfb insider Siemens and they give your program a little bit more power than old timers and counters would that you would use on the s5 PLC's on the s5 PLC's this sort of stuff didn't exist but when Siemens created s7 300 PLC's at s7 400 PLC's this is when the IEC standard started to come into place and this is what they began to create was these IEC blocks that could be used on any PLC that were universal to any PLC as I mentioned I didn't want to get too involved with SF Bay's I don't want to go through all of the other blocks that are available I don't also have to go through counter downs and counter up-and-downs or the other timers as we've already spoke about those in previous videos I just wanted to show you how SFA's are created inside a step seven how we assignment data blocks and how they are then used inside of the PLC now one thing you've got to watch out for is the current version of your PLC if you're working with the earlier versions of the s7 300 PLC's you may not have the full selection of SF B's and SF CS that are available inside of Siemens and that's because you work with an earlier version it's already preloaded with its information if you're working with newer PLC's chances are they've got the majority of the blocks that have been created by Siemens already pre-loaded on its PLC if it doesn't there are things called firmware upgrades which allow your PLC to get the newest software loaded onto it which may include the new s FPS and SF C's but it's just something to watch out for it you don't have the full selection of s FPS and SF C's it could be the firmware version of your PLC is slightly outdated it's no longer the newest version going and that there is system function blocks inside of step seven PLC now if you want to learn more about step seven and TI a portal what I recommend you doing is going to our website www.sceeto.com K going to our e-learning page and then having a look at our siemens step7 professional or if you're interested in the newer software TI a portal we also have allen bradley on there as well as well as some generic PLC and SCADA course to teach the correct ways of writing programs in today's industry I hope you've enjoyed this video on system function blocks inside a step some professional and I look forward to seeing you again next week see you later guys

Channel: Scantime Automation & Training

Views: 3,398

Keywords: scantime, siemens, step7 professional, system function blocks, sfb, tia portal, plc, scada, hmi, automation, plc programming, plc training, siemens training, siemens programming

Id: LQjnxWNmje4

Length: 21min 4sec (1264 seconds)

Published: Fri Jun 19 2020