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sal7

traffic light

8 posts in this topic

Hi again, This kinda follows from my other posts. What im trying to do is create an andon system which is activated through buttons on an MES/SCADA screens on a PC. I have configured the buttons to send certain values to memory words on the PLC which is working great. I am now stuck at the programming the PLC. I have got to a certain point but i cannnot figure out the other part of it which, is again due to my lack of experience and knowledge. What i have done so far is when a button is pressed on the Pc for example Safety Issue the red light blinks on the traffic light stack, when another button is pressed for acknowledgement the red light goes solid and stays solid until the resolved button is pressed and the green light comes to say everything is ok. This goes the same for Quality and Assitance required which are both Yellow and out of materials which is blue. If i press either of the Call/issue buttons the lights will blink simultaneously and go solid when i press the acknowledgement button respectifully. What i want to do is when for example the assitance required button is pressed and the safety issue button is pressed and when the assistance required is acknowledged and cleared i do no want the green light to come on because the safety issue is still occuring. This can be for all combinations of the issues. I only want the green light to come on when a problem or a combination of problems has been resolved. I have tried several times adjusting programme but it sill wont work I have attached a zip file because i could not attach the .twd file it wouldnt allow me, there is also a csv file. Regards, Sal andon.zip

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I read your very simple program......... but sorry I don't understand what is the problem. You have five green lights not only one. Which one are you talking about? I see the first one is lit only when all other fours are lit, and all those four are lit if red, yellow and blu lights are off respectively. (green light material has no interlock cause the word 3 is used only in this rung and I don't know how this (and all others) is managed). You are probably talking about this four green lights. If two different lights (yellow and red) were lit at the same time you wouldn't lit the two green lights till both those situations are solved. I don't think I have understood.........

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Hi, Thanks for taking the time to look at my issue. Sorry that i have not explained myself clearly. What i have is a traffic light stack. One RED, one YELLOW one GREEN and one BLUE. What im am trying to achieve is when the operator presses a safety issue button the green light goes off and the red light starts to flash, when the problem is acknowledged the red light than goes solid indicating a problem is being looked at. If in theory another button is pressed doesnt matter which one but say the teamleader request button is pressed the yellow light thats starts to flash (red light is still solid), the teamleader than acknowledges is the yellow light goes solid and than resolves it now at this stage there should be no green light because the red light is still on, but the yellow light should go off. What im trying to acheive is the green light should only come when there are no other lights on in other words when all the problems have been resolved. The reason why there are so many outputs to the ONE green light is because i was just experementing. Im very new to PLC programming and ran out of options any help would be appreciated. Regards, Sal

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High, Ive done another programme it seems like im getting closer but got a couple of issues with this new one. The green light which is output 4 does not go off when an issue button is pressed. When a second issue button is pressed and has not been acknowledged but the 1st issue is raised acknowledeged and resolved the green light comes on. I know in the programme that is what it is meant to do but i dont want to do that is there any solution to it. I have attached the latest programme and symbol table, sorry again for the zip but it is the only way i can show u what i have done. Regards, Sal andon4.zip

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Hi, Dont worry about it, ill figure it out somehow. Regards, Sal

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If I have got your problem, I easily solved as in the attachment. I wonder why are you using different words %mw0,1,2,3 and why different values for each word (1,2,3,4,5,6,7,8)? There's no problem, I just want to know the reason. You might write bits for instance and it would be the same but it could be helpful to you to analyze your choice in order to improve the way to solve any problem. Anyway I hope this is the right solution to your issue andon5.zip

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Yeah im not 2 sure why im using what im am using, its the only logical thing i could think of when doing it. Reason why i sed different memory words and different values for each word is when i configure the MES/SCADA software buttons i assign those buttons to send a value to %mw on the PLC (sorry if i seem like im telling you what you already know, im just explaining what im doing) Im not to sure how to write bits, if you could show me that would be great or even point me in the correct direction so that i can learn it. Regards, Sal

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Ah ive done it, using memory bits. Thanks, Sal Sorry I didnt seen your attachment until just now, ive done mine a little bit different but it works anyways, thanks, Sal

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