MODICON Concept Question

jimdi4

Member
Join Date
Aug 2004
Posts
108
Do you have to add "end" statments at the end of each ladder program in Concept just like youi do in the AB RS logix programs...Im new to the modicon COncept stuff and Im trying to add my logic that i already have progrmmed in contrologix to Concept but there are a few quirks.

One quirk is the timers..For each timer I use I have to create a seperate output ..it not like RS logix where you reference the timer block TT or EN or DN bits...You need to reference the output that the timer actuates. :(
 
I'm going to assume that you are using the 984 LL version of hte ladder logic, and not the IEC version. I am also going to assume that you mean each page when you talk about "each ladder program". The answer then is No, you don't need an "end" statement.

Actually, if you are taliking about the IEC version of ladder logic, the answer is still no.
 
Clarification

To clear up a little confusion I apparently created, I should point out that Concept is a programming package that supports several IEC compatible languages. One of these is Ladder Logic. It also supports another version of ladder logic that is compatible with the old 984 PLC product line. By getting the correct flavor of executive firmware you can use either version of ladder logic programming in several different PLCs, including the Quantum and Momentum among others.

The operation of the timers in either version is different from the Allen Bradley timers that you are used to. You really really need to read the manual closely to get the operation of the type of timer in the ladder logic version you are using, as it is confusing and non-intuitive. You do have to use a coil on the output of the timer, and use that coil's contacts in lieu of the "Done Bit" that is foind on most PLCs.

Another thing that is a pain with the IEC timers and an operator interface is you may have to convert the timer preset from an integer to time format. Go to the manuals for ddetails.

Among the things I don't like about the Modicon documentation is that they don't give examples for commonly used functions. Here is an example of a timer in the IEC version of ladder logic:

iec.jpg
 
And here is similar logic in the Concept 984 ladder logic flavor. Note that this dialect has separate timers for 0.1 second, 1.0 second, and other time bases. MAke sure you get the right one!

984.jpg
 
Thanks Tom thats just what I thought...


You are right the manuals having no visual documentation like AB has...

One more question on the timer timing bit....(I want to relate this to the AB TT bit).
Correct me if I am wrong please...So...

Timer Timing bit... If the timer is timing and counting through its preset time and I want to know this, I would just use a contact lets say a Normally Open contact of the coil. So when the timer is timing the Normally Open contact of the coil would be "ON" for the duration of the time. Normally Closed state when Timer is timing would be "OFF".

Timing Done bit....When timer has completed its time (TON of course) the Normally Open contact of the coil would close until timer is reset. When timer has completed its time the Normally Closed contact of the coil would open and remain open until timer reset. :)
 
It depends on which version of laddder logic you are using. The IEC version isn't the same as the 984 version. That's why I suggest you look at the manual description of the timer function. There are too many variations for me to cover them here.

However, I do suggest you do yourself a favor, and don't try to make correlations or direct translations between RSLogix and Concept. That is just going to cause problems. Forget TDN and XIO and GEQ and so on. Just look at the Concept software as it's own entity, and think in terms of functions - this location on the timer turns on when the timer is done, and this thingy is a contact that closes if it is on, and this is a comparison between two numbers and if it is greater than or equal this happens, and so on.

In the long run your learning curve will be shorter and you will be happier. I've converted logic to a lot of different platforms, and trust me, in the long run you will do better by thinking in terms of function and not thinking in syntax and terms used by another package.
 

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