Square D Symar to RSlogix 5000 PLC code 2

Hello guys, I need to understand how instructions work in Square D Symax PLC. I need to upgrade old code which is in Square D symax SCP401 controller and my new PLC will compactLogix. Also, how these instruction will configured in Studio 5000. Posting some images below to understand instructions

I think these might be good starting points:


https://download.schneider-electric...p_File_Name=30598-730.pdf&p_Doc_Ref=30598-730


https://literature.rockwellautomation.com/idc/groups/literature/documents/rm/1756-rm003_-en-p.pdf

but they do assume you understand ladder logic. Is that the case?

The first rung 190 is a 'not equals' followed by a 'Greater than or equal to'. HTe net result is a single 'Greater than' that is true when register 190 is greater than register 194. 'S' refers to storage registers - signed 16-bit integers that vary in value for -32768 to + 32767.

The S2007 = S2005;S2006 rung copies the contents of S2005 into S2007 and S2006 into S2008.

The next rung is a repeat Let that sets zeros into 120 registers starting at S1451. The arrow by the S1405 pointer indicates all 120 are zeroed in a single operation.

The next run copies the value in S14 into one element of the array starting at S1451. The result element is determined by the pointer in S1401. The pointer value must range from 1 to 120.

The last let is a one-operation per scan thing where the S1403 pointer increments on each scan. I forget what the 'DUP' things mean.

Further clarification:

M means 'Matrix' - an array of integer registers.

S means 'Storage Register' - a single integer value.

M101 with a size of 100 refers to S101 through S200.

- - - - -

Not that you asked for this - but:

The Symax 400 was a great CPU for it's time but Square D painted themselves into a corner with some architecture definition problems that they couldn't recover from. The fixed data table size turned out to be a problem. Taking a 500kbaud network and choking it through a 9600 baud serial port was a disaster. The protocol used 8 data bits plus parity which did not play well with the modems of that era. They did manage to avoid the headaches that AB had with block transfers but the fixed size data mapping to discrete I/O slots meant that the I/O architecture was dated. They couldn't come up with 16 or 32 point modules to plug into those slots. Their remote I/O Local/Remote interface protocol was done by a subcontractor and not really documented. This discouraged third parties from making stuff to hit that bus. They jumped on the Ethernet bandwagon too soon so they used coax and didn't use TCP.

Most of these problems are now visible with hindsight and I look back fondly on the many Symax projects that we did. The DOS software was stable and did not suffer from constant version changes. The I/O was big enough that you could work with it - not like some of this new stuff that is nearly impossible to terminate with adult size hands. The output modules had real aluminum in them and the input modules pulled a decent amount of current. There are parts of it that I miss.

Thank you Corsair, I really appreciate you help on this thread. Thats really put light on many queries I am having in this SCP401 PLC code.
Can you please look at this thread, which I have posted earlier, and if you explain these rung in a similar way. That will really helpful.
Please find the link below for previous thread:-

http://www.plctalk.net/qanda/showthread.php?t=135281

I think some of the confusion results from what Square D had to do with the printouts - the comparison was actually a '>=' but it may show on the printout as '>'. The bitwise AND, OR, and Exclusive OR symbols may not be clear. Matrix indexes begin at '1' and not '0'. Integer arrays begin with 'M', floating point arrays with 'A'.

Please do not take offense - we're all at different points in our experience and we all were where you are now - but if you cannot figure out the Symax you are nowhere near ready to tackle the Logix. I'm not saying to drop the project. I am saying that you need to bury yourself in both product manuals and be certain of what the complete Symax program is doing before going further. This will probably take more time then what has been allocated for the job - which is typical for our industry.

With the LET boxes pay close attention to see if there is a 'T' to the left side of the LET. Big difference.

Corsair said:

I think some of the confusion results from what Square D had to do with the printouts - the comparison was actually a '>=' but it may show on the printout as '>'. The bitwise AND, OR, and Exclusive OR symbols may not be clear. Matrix indexes begin at '1' and not '0'. Integer arrays begin with 'M', floating point arrays with 'A'.

Please do not take offense - we're all at different points in our experience and we all were where you are now - but if you cannot figure out the Symax you are nowhere near ready to tackle the Logix. I'm not saying to drop the project. I am saying that you need to bury yourself in both product manuals and be certain of what the complete Symax program is doing before going further. This will probably take more time then what has been allocated for the job - which is typical for our industry.

Click to expand...

Thank you for helping me out. Right now, I am figuring out how the code works using programming manual. I don't have program file, using notepad file provided by the customer from site which have square D SCP-401 PLC Program and have to decode the PLC code for conversion into new AB PLC code., that's the challenge I am facing, so basically there are some instruction that configured differently and can't actually figure out from the programming manual that how it actually works and can't even test as well. So seeking help here, if someone have expertise in it.