efigalaxie
Member
Hello!! I work as an electrician/technician in a steel mill. Most of the things we are using are antiquated..... IE 90-30/90-70 with logicmaster 90.
I wanted to re-educate myself on PLCs, so here goes. I constructed a model of a 4 way intersection with left turn lanes. I have 4 LEDs per direction - Red/Yellow/Green/Blue (Left Turn Go)
I have 8 switches for traffic presence, 2 for emergency services.
I have the operation set thus:
I go into a cycle - say...green for left turn in north and south. All else is red. I have a master timer for that cycle. The cycle will be no greater than the set interval of the timer. I have another timer that operates off the traffic detection in the GO lanes. If traffic isn't detected every so many seconds, I advance the elapsed time in the master timer so that there are fewer seconds in the cycle. Then I go to yellow, then red. I have everything red for a second then switch to green straight through....and so on. All cycles are basically identical except for the time allotted.
My Boss kind of wants me to make it so every direction is independent and self adjusting without directly affecting the others. Say a green for a left turn when opposing traffic is sparse.
I think there is a simpler way to do this whole thing. As it is I have quite a few timers. I am thinking a counter/timer tandem.........
You gentlemen have any clues or pointers?? I have looked on the web and most of what I have seen doesn't even have left turns.
I think what my boss is requesting is more complex than most traffic lights....I see them go through an ordered sequence in a pattern. The sequences are faster or slower depending on traffic, but they do not alter the sequence itself.... IE Green left turn, then green straight both ways, then since no opposing traffic is coming, back to a green left THEN on to the next sequence where the other directions go.
I got clever with my outputs and was cutting lights off and on by passing words into the output registers. He didn't like that. Anyways, Any tips would be appreciated. I want to be done with this and go play with analog I/O. Keep in min this is GE Fanuc and the timers aren't as nice as those in the AB stuff.
I wanted to re-educate myself on PLCs, so here goes. I constructed a model of a 4 way intersection with left turn lanes. I have 4 LEDs per direction - Red/Yellow/Green/Blue (Left Turn Go)
I have 8 switches for traffic presence, 2 for emergency services.
I have the operation set thus:
I go into a cycle - say...green for left turn in north and south. All else is red. I have a master timer for that cycle. The cycle will be no greater than the set interval of the timer. I have another timer that operates off the traffic detection in the GO lanes. If traffic isn't detected every so many seconds, I advance the elapsed time in the master timer so that there are fewer seconds in the cycle. Then I go to yellow, then red. I have everything red for a second then switch to green straight through....and so on. All cycles are basically identical except for the time allotted.
My Boss kind of wants me to make it so every direction is independent and self adjusting without directly affecting the others. Say a green for a left turn when opposing traffic is sparse.
I think there is a simpler way to do this whole thing. As it is I have quite a few timers. I am thinking a counter/timer tandem.........
You gentlemen have any clues or pointers?? I have looked on the web and most of what I have seen doesn't even have left turns.
I think what my boss is requesting is more complex than most traffic lights....I see them go through an ordered sequence in a pattern. The sequences are faster or slower depending on traffic, but they do not alter the sequence itself.... IE Green left turn, then green straight both ways, then since no opposing traffic is coming, back to a green left THEN on to the next sequence where the other directions go.
I got clever with my outputs and was cutting lights off and on by passing words into the output registers. He didn't like that. Anyways, Any tips would be appreciated. I want to be done with this and go play with analog I/O. Keep in min this is GE Fanuc and the timers aren't as nice as those in the AB stuff.
