AB RS Logix 500 Simple questions...

[uptown47]

Hi All

I'm brand new to AB (although very familiar with Siemens) and I'm using RS Logix 500. I've been asked to do some mods to a system. I need to identify what IO is free. How do I do this through the software?

Also, when I download to the PLC I don't want it to switch to STOP mode. Do I need to do all my mods in RUN mode in order to achieve this?

Many thanks

 

[brucechase]

Open the I/O data file and click on the useage button. If it is addressed in the program, it will have an X on that address. You can then right-click and find all. Also, just because the I/O is not used in the program that doesn't mean there is not something wired to it. I always make sure there is nothing landed on the terminal.

As for editing without stopping the program, that is where you have to do an online edit. Modify the rung, accept the edit, test the edit, then assemble the edit. This will prevent the process from shutting down.

 

[uptown47]

Bruce

How do I find out which module is which address?

In S7 I would look at the hardware config to find out how each module in each slot is addressed. How do I do the same in AB?

Many thanks

 

[JesperMP]

Hello uptown47.

You cannot download a program without stopping the CPU.
In case your PLC is an ML1100 or an SLC5/03 or better, then you can edit online with no need to switch to STOP mode (is is called PROG mode).
So for minor changes, it is actually easier to make the changes online.
For bigger changes, you can still do it, but it takes some care and attention. You basically delete all the rungs that has to be changed, and paste the changed rungs from the offline file. When ready, you do the test-edits, and assemble-edits.
Notice that you cannot download new code or data files, or change the size of data files in RUN mode.

ML1000, ML1200, ML1500 and SLC5/01 and SLC5/02 do not have online editing. Therefore avoid these if possible.

 

[JesperMP]

How do I find out which module is which address?

In S7 I would look at the hardware config to find out how each module in each slot is addressed. How do I do the same in AB?

In ML and SLC500, the I/o adresses are determined by the slot position.
I:n or O:n where n is the slot number.
Onboard i/o has slot number "0".
Modular i/o slots start from "1".

 

[uptown47]

Thanks for the info.

I am trying to read in the level of a tank. There are some other tank levels being read by the software using the SCP (Scaled With Parameters) instruction. They take in an "N" number such as N7:0
If I want to create a new one are there any rules as to what number I should be using?

Do these numbers relate to analogue inputs in some way?
How do I find out what "N" numbers I can use and what inputs they relate to?

I'm very sorry if these are simple/stupid questions but I have absolutely zero AB experience.

Many thanks for your patience.

 

[JesperMP]

AB "SCP" is extremely similar to S7 FC105 "SCALE".
However, AB math one-ups S7 math as you can freely mix integer and floating point math.
If the SCP instruction encounters a floating point variable as one of the parameters, then the entire computation is done with floating point precision.

Yes, you typically convert from the raw input signal to engineering values with the SCP instruction. The primary input to the SCP instruction is then an I:n.x address. "n" = slot number, "x"=channel number.

 

[uptown47]

Here is my IO Config and the N's and I's that are used.

I can't see anything in slot number 7 so I'm wondering how the program is addressing N7:x

Also the N's go up to N7:80 and also there are some references to N9:0 etc...

How do these relate to "real world" inputs?? How are the values getting in to the PLC?

Many thanks

 

[MorphuisOGrady]

N7:x is referring to data table. N7 is a file set used to store numeric values or bit information. Think of it as your S7 Data Blocks or Memory Area.

N9: These are data files that you create.They can be dinfed as bit, timer, counter, or integer data storage etc.

 

[uptown47]

Ahh, I see.

Some of these N7 values are tank levels. How does the value get into the N7 area then?

In S7 I would transfer an analogue input into a Data Block.

How is it done in AB as there is only one instance of N7:1 in the program and it is being read by a Scale With Parameters block.?

Many thanks for your continued support

 

[bkottaras]

Here is my IO Config and the N's and I's that are used.

I can't see anything in slot number 7 so I'm wondering how the program is addressing N7:x

Also the N's go up to N7:80 and also there are some references to N9:0 etc...

How do these relate to "real world" inputs?? How are the values getting in to the PLC?

Many thanks

N7 (integer file) is created by default when you first create a new project.
You can add more files as described above if need be.
You can create a new file and call it 50, select integer as data and length of 10 so you'll end up with an N50 file containing N50:0-N50-9 total of 10 words

 

[aidamcg]

N stands for Integer files. In SLC these are files of size 16 bits and by default data table location 7 is reserved for integer files.Data table location 8 is reserved for floating point and after that it is at the discretion of the programmer what they want to call 9,10,11 etc in the data table.The N9:0 in your case is just more Integer data table files. The size of these is at the discretion of the programmer and the memory limits of the controller. Hence why you see N7:80 where the programmer has created an integer data table 86 elements big.
The real world values from the physical I/O are usually mapped to these integer files for use in different functions such as SCP,MOV,COP etc
In your I/O setup slots 2-5 have input cards so the addressing would be I:2/0 - I:2/15 ,I:5/0 - I:5/15. To see if any of these inputs are free you would select the data table for Inputs which I and then select usage. Anything with a X is in use. Note these are digital input cards so all your analogue must be coming through the devicenet module. I am not familiar with them.
If you want to increase or create a new data table you will have to be offline and then download the program with the increased or new data table. You can create a new N10 file as many elements big as you want dependant on memory constraints. You can make edits to logic online and test and if happy with them assemble them but data table resizing has to be done offline and downloaded. Hope this helps

Regards

Aidan

 

[uptown47]

Thanks for the info Aidan


I'll have to look into what's connected via the devicenet. I presume its some modules with analogue inputs maybe??

Although I'm still not clear how we go from an analogue input to an N7:x number ??

Anyone know whether this will be done over devicenet??


Edit.. just realised I forgot to thank BK too for his info

 

[aidamcg]

Have a look at the attached and see if it makes sense. N7:X are 16 bit words and can be addressed to bit level eg N7:0/1 but are used mainly for storing decimal values up to 65536 hence the name integer data table files.

 

[uptown47]

Aidan


Thanks very much for the example. It does make sense to me (surprisingly enough!)

A big thank you!

Cheers