RSLogix500 Export/Import Bug

[ppelegris]

Hello everyone,

I am new to the forum and I am currently working on a program that converts FBD schematics to Ladder Logic targeting Allen Bradley RSLogix500

The export format I am using is the SLC library file format, which is the only ASCII based format supported by RSLogix.
I’ve came across a serious bug while importing the SLC files I generate. The bug can be replicated easily by

A. Creating any ladder logic program, assigning initial values to the I/O.
B. Saving the file as an SLC library file.
C. Closing the file and the reopening it.
D. You will now notice that not all the initial values show up in the data files.

I am attaching an slc file that demonstrates the problem
(the forum doesn't allow an slc attachment so please rename the file from init.txt to inti.slc)

Cpu :
START 1747-L551B % 1747-L551B/C 5/05 CPU - 16K Mem. OS501 Series C FRN 3-9 %

IO Slots :
SLOT 1 1746-I*8 % Any 8pt Discrete Input Module % SCAN_IN 1 SCAN_OUT 0 IOCARD -6448 24 14890 176 6496 212 -28694 116 76 237 24 0
SLOT 2 1746-I*8 % Any 8pt Discrete Input Module % SCAN_IN 1 SCAN_OUT 0 IOCARD -6448 24 14890 176 6496 212 -28694 116 76 237 24 0
SLOT 3 1746-O*8 % Any 8pt Discrete Output Module % SCAN_IN 0 SCAN_OUT 1 IOCARD -6448 24 14890 176 6496 212 -28694 116 76 237 24 0

Data Files :

DATA O:3
% O:3.0 % 0X0008

DATA I:1
% I:1.0 % 0X0002

DATA I:2
% I:2.0 % 0X0004

The bug is that even if I:2.0 has the value 4 it is not imported by RSLogix which shows 0 when imported
So RSLogix cannot basically import its own export correctly.

I would appreciate any help on this

 

[Bit_Bucket_07]

That's not a bug. That is a feature. Why would you assume that data values should be imported along with the program logic?

 

[ppelegris]

That's not a bug. That is a feature. Why would you assume that data values should be imported along with the program logic?

Thanks for your reply,

I might not have made my point clear.

You may have a set of initial values if you wish to.

RSlogix is doing that fine if you choose to export and import in its native RSS format but that's not true for the SLC format.

In the example I gave the value 4 will end up in I:1.0, so what it seems to be doing is that instead of assigning a value to its respective data file is just assigning all values to the first data file.

So I:1.0 ends up with 4 and I:2.0 empty
Instead of I:1.0 -> 2 and I:2.0 -> 4

 

[rdrast]

What is the point?
Inputs are filled in by the SLC processor anyway, not user values.

How are ACTUAL user data tables handled? (N, B, F, etc)

 

[ppelegris]

What is the point?
Inputs are filled in by the SLC processor anyway, not user values.

How are ACTUAL user data tables handled? (N, B, F, etc)

I appreciate what you are saying rdrast, but are you suggesting that this is the desired behavior from RSLogix ? Which is reading some of that values and ignoring the rest ?

P.S. There's no issue with the N,B,F tables just with I/O

 

[rdrast]

It is the only behavior possible. As soon as the processor goes into run, the I/O tables are handled by the physical world and the program logic. Force files are downloaded, but there is no point in downloading I/O images.

The SLC-500 series (and I assume Micrologix) also don't generally allow external access to the I/O tables IIRC... As of the last time I used it, WonderWare wouldn't even attempt to read or write them.

 

[robertmee]

It is the only behavior possible. As soon as the processor goes into run, the I/O tables are handled by the physical world and the program logic. Force files are downloaded, but there is no point in downloading I/O images.

The SLC-500 series (and I assume Micrologix) also don't generally allow external access to the I/O tables IIRC... As of the last time I used it, WonderWare wouldn't even attempt to read or write them.

The DASAB server for SLC can read from the I/O tables but it's a bit hairy, as everything address wise is word based, not slot based. So it's fine if you are mapping Discrete 16 pt modules that land on word boundaries. But as soon as you introduce an analog module or 32pt module into the mix, every address gets offset by the additional words. For that reason, I never use the DASAB server to access SLC I/O.