How do you guys create a sequence of steps logic?

[Penko Mitev 0]

Hello guys! As I mentioned in my introductory topic, I was stuck with Logo and had to take it out from the machine panel and install Scheider. Here is my problem. I have had experience with Delta(the same interface as Omron) and lack a lot of features in Logo. For example in Delta, I have the following: LD= K1 D100 ---> ld X1, SET Y1(The output is SET, so it remains 1 until it is reset with RST) LD = K2 D100 --> ld X1, ld X2, OUT Y3(the output is 1 only until the previous conditions are met) This can be separated in a whole subprogram and call it only when necessary. Okay, it is sure Logo can't handle subprograms. Furthermore, I didn't see a way to implement what I want with funciton blocks(the LADDER way). The problem is everything is executed at the same time and I can't create a sequence of steps. I just can't imagine it with the rungs I can develop in Logo. For example something must activate first, after it another mechanism and if the first is OFF, then another thing, etc... So, how do you guys create a sequence of steps, let's call it Step ladder, but it is not absolutely step ladder. It is a question of having one variable and doing actions on different values of this variable. This is a very easy way to create steps which will execute one after another and not in another order/way. I tried with the help of markers(M), but it didn't resolve my problem. Also, what I noticed in Logo is that there is no SET function, but OUT only. This is pretty stupid and really was one of the reasons for me to abandon Logo and install Schneider. Moreover, something also very dummy is the impossibility to create more than one connection to an output. It disappears from the menu when creating new COIL block. That's terrible! Now, when it is not critical for the deadline, I just want to improve my skills, I will make the machine with Schneider, but one Logo remains and surely I have to implement it in a further machine, so in order to do this I have to have my difficulties overcome :). Looking forward to hearing your suggestions, Penko

[Crossbow 297]

Try using the set/reset and latching M bits for your steps in your ladder. As for your set and reset, did you review the programming manual? There is a set/reset function. And as for the multiple connections to an output, look at the OR instruction. Seems to me like you did not even look at the programming manual.

[Groo 7]

Be aware the the LOGO was designed to be an intelligent relay. It was never expected perform complicated logic.

[Crossbow 297]

That was my first response too but I deleted it. People think intelligent relays are extremely powerful, but they are not. They are not TRUE PLCs.

[Penko Mitev 0]

Groo, thank you for confirming my opinion. Crossbow, I have taken multiple looks on the programming manual, I never ask without having read everything available in the manual. Yes, of course, sometimes it's possible that I miss something, that's what forums are about. The reason for my interest in Logo was that before I started programming my father's machine there was a guy who was like an employee of the company. He has programmed all machines for the 10 years history of the company.This makes more than 300-400 machines. From very simple, to more advanced, but all with Logo and S7-200. I remembered some of the Logo-powered and thought I would also succeed with Logo, but it was a real nasty for me who has gotten used to something higher(Delta(Mitsubishi like interface)) PLC. It was a real shock. I am happy my father decided to remove the Logo with the motive we will always find where to put it and we installed Twido. Twido is very easy to program and is related to what I am used to :). Thank you guys one more time! Penko