Q-series PLC

[Duffanator 1]

Hey all, I had just recently started using the Q-series PLC and for the most part I really like it, it is far superior to the A-series and has many more cool options to play with. The only thing I don't like is that there seems to be no good way of finding information out without having to sort through 100's of PDF files trying to find one simple answer. Most of the stuff I figured out on my own but there are some things I'm still not sure of and I was hoping someone here would know the answer to some or all of my questions. 1) How does the scanning change if your running multiple programs? Does the CPU scan all the programs simutaniously or does it scan one then the next then the next etc.... I would like to know if it's faster to write one big program, many little programs or if it makes no difference at all. 2) I was playing with the fixed scan time option for different programs but when I set a program to scan say at 1 second intervals it only runs once and then never runs again. Is there something I'm missing with this? I don't see any other options so I'm kind of confused with that. 3) (This I can find absolutly no information for) How do you use the high speed interupt programs, I could really use this if I could figure out how it works I can't figure out how to set it up or how to implement it when it is set up. 4) (This is more specific question) I'm running a fairly high speed machine with a Q-series and it needs to pick up registration marks on printed film with a photoeye as the film is running through the machine. This works fine until I connected Citect to the PLC to gather statistical information from the PLC. Now it misses the registration mark sometimes. Citect is only polling the PLC every .250 seconds how much does it slow the scan time when you are requesting I/O and D register information from an HMI or remote monitoring software such as Citect? I would think this would be negligable but apparently it makes a difference. 5) When using function blocks written in Structured Text does it constantly scan the function blocks or wait until it gets to the function block in the program to scan through it? Also is structured text slower, faster or the same scan time speed? I really like the function block feature but if it's slowing down the scan time I'd rather have the time than the convenience. If anyone knows the answer to some or all of these questions your help would be greatly appreciated. Thank you!

[Gambit 326]

I would suggest if you wanty to use FB to use GX IEC Developer it's more versitile

[funfrok 0]

1- CPU scans programs one by one according to the parameters. One big program is faster than multiple programs especially if there are different kind of programs. But it won't be much difference if there aren't a lot of them i guess. 4- Communication with pc is done in end processing, after scan is finished. If there are a lot of communication it would definitely increase overall scan time. For Citect you can arrange variables consecutively, and using bit devices if possible . Look for SD540,SD541 . In normal scan end processing time is not show (i'm not sure). I've never used but there are parameters to limit end processing time. In QnU series,look for "Service Processing Time" in "Plc System" in plc parameters. In older series there is a special register SD*** , i think i saw sometime ago but couldn't find now. By the way, 250 ms refresh time is too much i think. Why not 1 second? Edited 18 Feb 2009 by funfrok

[Duffanator 1]

Cool, thanks for the info. I tried 1 second refresh time and it didn't work very well with the trending I'm doing. I wanted to trend the vacuum level of the machine and it's so quick that I wouldn't get an accurate trend with 1 second refresh. I'll post my program so you can take a look at the settings. I'm always looking for ways to make things better so if anyone has any ideas or helpfull hints that would be great. I appreciate the feedback, thanks! SLM_Tiromat.zip

[panic mode 246]

Q processors are very fast and most of the time i scan all files all the time. even with lots of special cards (reading and writing buffers takes toll), several network connections etc. no matter what i throw at it, scan time is in 2-3ms range (once i saw something like, i don't know 4 or 5ms while editing). what are you trying to do, what kind of scan time you are looking for and why bother with fixed scan time (or 1sec scan when you can have 1ms or less)? I am not sure what you mean by 100s of PDFs. there is: a) one manual for GX Developer to become familiar with enviroment, addressing, downloading etc. b) one hardware and one user manual for each card (processor, ananlog input, analog output, CC-Link card, ethernet card etc.). the hardware manuals are very short, usually few pages showing the most basic info. user manuals contain details on particular product. If it is CPU, that would be instructions manual, if it is special card, that would be all I/Os, buffers, code samples and troublshooting section. i like the way manuals are structured and numbered. you can find manuals by numbers and you can easily tell which one is newer, one manual has everything you need to know about the product (compliance, revisions, specs, programming example, troubleshooting, etc.). try doing project with siemens for example and you will see what i mean. i do agree that GX developer has way to go (including better help) but if that means application that has slower response, i'd rather keep it the way it's now. it's not much of a problem to have pdf in another window and alt-tab between the two. the only problem i see is with the older manuals which have been scanned into PDFs. page content on those documents are images so one cannot do text search.

[Duffanator 1]

Well, it's not something that is killing my program it was more of a "This looks neat, how do I make it work?" kind of thing. I have one program that just sends errors through e-mail but that doesn't have to scan every time so I wanted to have it scan every second. There's a good posibility that it will have next to no effect on the actual scan time but I wanted to try it any way. The problem was that even when I set it up to run every second then it didn't run at all. It's not so much that I need to have it that way but more of I was trying it and it wasn't working. Just wondering what needs to be done to make it work. Also the 100's of PDF files was an exaggeration, it's just frustrating when you have to wade through a PDF for something that should be in a help file. I don't get to spend my whole day writting PLC programs I have lots of other stuff I have to do at work too so spending half my time trying to find a simple answer in a PDF or constantly calling Mitsubishi support isn't something I'm very fond of. Just my opinion! Edited 18 Feb 2009 by Duffanator

[funfrok 0]

I remember that, you must enable interrupts for fixed scan programs. I had trouble making it work, when i tried. :) You should put an EI instruction to enable interrupts. Edit: About manuals, at first it is hard, but when you are used to Mitsubishi manuals, you can find what you are looking for easily. Still i have problems locating the pdf file itself. I agree about hundreds of manual, there are plenty of manuals that makes it hard to find the correct one. New modules' manuals are harder to find, not all Mitsubishi sites have them. US site is (meau) is the best i think. Edited 18 Feb 2009 by funfrok

[kaare_t 155]

1: For multitasking and/or time-critical applications, you could run multiple CPU's....... 2: You say that you are running some part of the program every second, what do you mean? Are you setting a fixed scan-time, or are you running some tasks/program-parts every second? How do you call these program-parts? 3: Already answered...!? 4: Where's the problem? In Citect or in the PLC? 5: I'm using GX IEC Developer. I'm not sure of the options in GX Developer, but in GX IEC Developer you can select "MacroCode". If you enable MacroCode, the function block will be inserted as any other code, and the actual compiled code will look like you did not create a function block. You can look at this by right-click the selected network, and press "Show Melesec Code". If you de-select "MacroCode", the function block is inserted as a sub-routine with a call to that specific code.