new member,logixpro student

[ijr900]

Hello Lancie1 and everybody else,great to get some feedback,this forum and the people on it are a great help. Rung 0 Branch 2 O:2/4 Unlatch full light is not a valid command and wouldnt work on a plc,I used this because i have yet to do any bit shift work so the full light{latched on when level sensor goes true) is being used to register the status of the process.Without it the soleniod opens when the container is moved clear of the level sensor.When i know a how to flag bits will us the level sensor to flag a bit status and put that instruction in at Rung 0 Branch 2 .your suggestion of using just three parallel rungs at rung zero is a good one,It would make the programme easy to follow .The truth indicators looked like christmas tree lights.i will come back to this one later,thanks for comments,always welcome Ian

 

[ijr900]

hello randylud, If you would post the door sim that would be great,is the programme using bit flaging.It would help a lot to see a programme at this level thanks Ian

 

[Lancie1]

Can't thank you enough taking time and going through it. Also is there any better way of using internal addressing then N7:x/x?

You should assign names (symbols) to each address so that you can refer to them by names from then on. As for address display methods:

N7:y/z
N7: = File Type
y = Slot Number
z = Bit Number

Alternate display option, selectable from RSLogix menu:
N7:x.y/z
N7: = File Type
x = Slot Number
y = Word Number
z = Bit Number

Alternate method to type in (enter) an address, that works in most instructions:
N7:x.y.z
N7: = File Type
x = Slot Number
y = Word Number
z = Bit Number

 

[randylud]

Door exercise #4

hello randylud, If you would post the door sim that would be great,is the programme using bit flaging.It would help a lot to see a programme at this level thanks Ian

http://www.plcs.net/downloads/index.php?&direction=0&order=&directory=Allen_Bradley it is available in the downloads section at this link.

 

[AlexKall]

You should assign names (symbols) to each address so that you can refer to them by names from then on. As for address display methods:

N7:y/z
N7: = File Type
y = Slot Number
z = Bit Number

Alternate display option, selectable from RSLogix menu:
N7:x.y/z
N7: = File Type
x = Slot Number
y = Word Number
z = Bit Number

Alternate method to type in (enter) an address, that works in most instructions:
N7:x.y.z
N7: = File Type
x = Slot Number
y = Word Number
z = Bit Number

What is slot number refering to? Oh and how would I go about naming an address in AB software (in this case the Simulator)?

Thank you

 

[randylud]

Alex, the AB addressing scheme used for the SLC500 family or the LogixPro simulator is as follows:
I=input, O=output and for an input or output address the address is completed by adding I/O module information so that the processor knows what point you are interested in. So a typical address might be:
I:1/8 where the I=input, : is just a separator, 1 is the slot number in the I/O rack where the input module is located and the / separates the slot number from the actual terminal number where the wire is connected, 8 in this example. The same analogy applies to an output address.
For words in the data table that are not I/O points the format is much the same but of course there is no slot number or terminal point. Typically this might be:
N7:3 or N7:3/5 where N=integer number register, 7=file number, : is that separator again, 3 is the word number in the file in both addresses, / is a separator between the word and the bit number which is 5 in the second example. Words in the data table are 16 bits long and you can access any of these bits by using the bit level address N7:3/5 in this example. The data table contains an number of different register types for different purposes, such as timers and counters. Each data table address, other than input or output, can have up to 256 words in each register. Of course the limit on words or programming instructions is based on how much memory you have.
To assign addresses in the LogixPro simulator you have to use the I/O simulator or one of the other sims that are part of the package. In the upper left of the main LogixPro screen there are some drop down menus. The simulations menu is between the edit and settings tab. Once you have chosen a simulation, I believe you will see where to assign addresses. Also, it is helpful to go through the student exercises located in the help tab.
I hope this clears up some things and good luck programming.

 

[AlexKall]

Thank you randylud! Great explanation! As I program other brands of PLC's I should of known what slot was but for some reason it did not connect in my brain, but with your explanation it connected instantly

Great explanation on N7, one question. As the 7 is the file number I can technicaly use N6 or N1? Might be a stupid question but as I'm used to Siemens and Mitsu this is somewhat like starting to crawl again as how you use the different features and designation of addresses is different, the ladder is another thing as it's the same thing in all PLC brands, the only difference is how to get a contact to the place you want using the different editors

Once again, thank you very much randylud!

 

[randylud]

Glad the old brain clicked, Alex. The AB line of processors from the PLC 5 and on thru the SLC 500 class all have the same basic data table structure. The data table is laid out like this:
O0 is reserved for outputs, and the O is obvious but the zero is not sometimes, and is seldom shown except in the actual program once you put it together. You are not required to enter the zero but it is the file number for Outputs.
I1 where I is obvious and the 1 is the file number for inputs
S2 where S is for system words and 2 is the file number
B3 where 3 is for Binary words/bits, sort of intended for logic usage much like old relay contacts were back in the day, and 3 is the file number.
T4 where T is for Timers and the 4 is, yes, you guessed it.
C5 where C is for Counters and the 5 is, . . .
R6 Where R is for contRol and the file number is 6
N7 where N is for iNteger values and 7 is the file number
F8 where F is for Floating point numbers and 8 is the file number
Now, these are reserved by AB and set in the processor as is and you can not change them or reassign them. Depending on processor type, the F file may or may not be there, as some processors do not have floating point capability. File numbers from 9 thru 255 are open, unless assigned by AB, for you to use as you see fit. So, you could have a N25, T16, C83, F22, R44, B92 etc file depending on your memory capacity. So, N255 is possible if you have the memory. Each file number can have 256 words depending on memory again. So, the N255 address could have N255:204 which is file number 255 and word 204 in that file.
This should clear things up some!

 

[Lancie1]

S2 where S is for system words and 2 is the file number

Not to quibble, but it is usually called the "Status" file, which has almost-but-not-quite the same context meaning as "System". System might even be a better name for it, but all the Rockwell and Allen-Bradley literature (that I have seen) refer to it as the Status file.

 

[randylud]

Point taken!

 

[AlexKall]

Thanks to both of you!

So N255:204/4 would be bit 4 (and 7 would be bit 7?) of word 204 of Integer file number 255? Or would that 4 be in the place of the actual number of the integer "word"? The first option would make more sense

 

[randylud]

Well, strictly speaking, N255:204/4 would be bit 5 since all of the words in these files are 16 bit and start at zero. That would make the 7, bit 8 in the 0 - 15 numbering system. But you are on track and would have noticed this little fact once you begin practicing the sims in LogixPro.

 

[AlexKall]

Thank you, clear now

 

[ijr900]

bit shift

thanks randilud, looking at your door sim has got me started with bit shifting,stripped it down to better understand its operation and changed to input output sim.ijr900

 

[Lancie1]

...looking at your door sim has got me started with bit shifting,...

Ian, your logic (using the two lamps, pushbuttons, and latches) is not usually referred to as an an example of "bit shifting". I would call it an example of using interlocks or flags. In other words, using a relay-type logic bit to prevent or inhibit another action.

Bit-Shift Logic usually means an array of bits that is shifted all-at-once for one position, when another bit (usually from an encoder or counter) goes high. Your LogixPro BSL and BSR instructions are used for this purpose.