Chris Morley wrote: > > I will try to work on any glaring bugs. > > > Hi Chris (and others ! )
In this email I'll try to list all the problems I encountered using the grafcet editor in EMC. First, this is the clp file we are talking about : http://filebin.ca/eztwq/custom.clp The first real bug I think I've found with the grafcet interpreter is : %X0, corresponding to the initial step state in my grafcet never become true, even if the state IS active. So I can't do the required initialisation for my system to work properly. This is what the grafcet should look like : http://imagebin.ca/view/CNXk0nbd.html And this is what is actually working, with a trick to go around the bug : http://imagebin.ca/view/DjYMF7X.html I changed the inital step for a step witch do nothing, and changed the "0" step for another one, and so it work as expected. The other problems more looks like limitations that real bugs. One really boring point is shown up in my grafcet by the steps with a "true" transition I had to add all along the thing. These must be used due to the editor limitation : It's impossible to make a link without linking a transition to a step. And it's also impossible to have two links pointing to the same step. This complicates the whole thing for nothing. E.G. the steps 9, 10, 12, 13, 14 are completely useless in the process I describe in this grafcet, there are here just to go around limitations. And sometimes you just can't use link at all, then you have to delete concerned step and transition, save, close EMC, then open it again, add again your step and transition, then if you are lucky the editor accept to make the link. And if you are even more lucky, the link work as expected. This is I think indeed a bug : sometimes links don't work : when the transition leading to the link is validated, the active state goes... nowhere. No more step become active, and the state machine is frozen up. I had to redraw several times the grafcet I use to get all the link working properly. For what I've seen, as you draw the thing without changing anything (i mean without deleting then redrawing), things work quite well. But when you start changing things, link problems starts. Also something problematic is that the editor is _SLOW_. I mean _VERY SLOW_ for example when editing steps properties and adding transition or something, you edit the first one, then OK, then change tool to add a transition, add it, edit its associated variable, OK, then the gui refresh and show the thing..., and then sometimes the gui stops refreshing at all, but still respond to mouse clicks, so you have to click blindly somewhere expecting you are above the "OK" button of the editor window, then the "save" button of the main window... And when looking at the grafcet working, it often takes several seconds to update, so you changed between lots of states before anything really cange on the GUI. That sounds quite strange to me, as the ladder part of the gui is also quite slow, but keeps responding in a usable manner. And considering evaluating the state of a state machine is not something that requires so many calculations, why is it so slow ? Another limitation/bug : the "add" and "insert" buttons in the grafcet editor wont work, using them froze up the whole thing. So ou can only use "modify" on the grafcet editor. Works well as you don't need your state machine to be larger than the default window... Yeah, you can use two or three or more sections if you need a larger graph, but to achieve this you must add states only to trigg a transition on the next section, this add useless complexity to your process. And of course with the risk of error or sync problem between sections like you can have when making a state machine using only ladder logic. But even with those limitations and problems, I have to say grafcet in EMC works quite well. It's really usefull everywhere you need a state machine. Tool changer automatisation is a perfect example that will speak for most of you. But could do lots of other useful things. Like switching glues tanks :) Or controlling coolant system, or... anything. I also seriously consider using hal and classicladder/grafcet to use a PC as automatic system for controlling things like the ventilation system and lights of our building. I will write something to improve the doc, and I will add my stuff to the wiki as a complete example of grafcet usage. But no time for now, I must use the machine (and its working grafcet :P ) to make, then sell some PV panels before :) yann ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
