Other than going from serial to Ethernet communications I cannot see much benefit in changing an SLC 5/03 processor to a SLC 5/05. But, sometimes that can be reason enough...
I have 12 x SLC processors and 10 x various older PanelView HMIs on the same network here all involved in a SWPHS (Strap|Wrap|Pallet|Handling|System). They were all originally 5/03's using the DH-485 protocol. There is so much messaging data being communicated that we were experiencing frequent lockups, requiring one or more processors to be Run Mode cycled to clear the buffers. I had done all I can or know to optimize and limit the occurrences, but really the DH-485 network does not have the bandwidth. I've been phasing the 5/03's out over the last couple of years for 5/05's, which converts each of these processors to Ethernet communications. 5 of the 12 processors are done so far (hard to get downtime), and also 2 of the HMI are now PanelView Plus 1000 on Ethernet (had them in stock). They are also all through a Stratix 8000 switch now. Already we have seen the number of lockups drastically reduce to every other few months. I have all 7 remaining replacement processors purchased and ready to go with converted programs. We get second hand processors heavily discounted from Lektronix as part exchange with the 5/03's, so financially the cost of doing this is not so crazy compared to a proper upgrade, which is not really necessary and does have its complications - for this particular application...
GaryS said:
...One option is leave the SCL rack in place and make it a remote rack using the original hardware...
You have to be careful when considering converting an existing SLC chassis to a Distributed chassis for a newer platform. You can replace the processor in slot 0 with a 1747-AENTR Ethernet communications adapter which will then take control of the chassis modules to be reported back to the new controller. However, the AENTR does not support certain modules - for instance, the 1747-SN module, of which our chassis have several, which are controlling multiple Flex Remote I/O racks in the field. The racks would need to be upgraded to Ethernet. Also the 1747-SDN DeviceNet scanner module is not supported, which we also have in certain chassis. Many PowerFlex 40 drives would need their COMM-D modules changed out for Ethernet COMM-E modules and enough switch port capacity provided. The Ethernet node count created here would have a significant influence on the new processor selection process.
Also, the AENTR does not support local expansion chassis (second chassis with expander cable) so a second AENTR would be required for all local modules beyond the first 13 modules.
The AENTR also does not support third-party 1746 modules. This could be very important, especially if there are speciality modules such as stepper, or the like.
The purchase and steep learning curve of Logix 5000 software, if not already available, may be another important consideration for certain cash strapped or inexperienced users.
And so on...
These considerations could be the deciding factor between a part migration or a full rip and replace, which could become much more involved or costly than initially expected. Especially if a third-party has to get involved.
That's not intended to dissuade anyone from considering migrating an SLC platform in part or full, but more intended to point out that scenarios may exist where it makes more sense to just upgrade the processor or another component within the architecture, for a relatively simple but important reason, rather than considering a possibly unecessary upgrade.
It is, as always, application dependant...
So, back to this application -
I'm sensing that, with your self professed limited experience, you are looking to move to Ethernet and have learned of the SLC 5/05 Ethernet processor and how it would be a relatively simple and proper conversion and replacement to achieve such a goal. Also, going to the PanelView Plus 700 would facilitate a move to Ethernet for the HMI. That's all fine.
Your "Rail Switch" I take is a reference to some form of DIN rail mounted network switch, which sounds "OK". There are a wide variety of those available for selection out there so if you have one in mind and want any further advice on it then tell us what make/model it is and some of us may be able to assess its suitability.
As is being pointed out to you, there are more modern options available if looking to migrate to an Ethernet based platform. You would need to consider, similar to the above, whether you think it necessary or feasable to move up in both hardware and software levels to the likes of the Logix 5000 platform. You might not have Logix 5000 software or have any experience using it. Also, you might already have the SLC 5/05 processor and so it may make more sense to keep it simple and just do this minor upgrade.
The program conversion is pretty straight forward. Just be careful to review any Message (MSG) instructions that may be in the program. These may be configured for serial communications and do not automatically convert to an Ethernet configuration when you change the controller type to SLC 5/05. Do not change the configuration within existing MSG instructions. Instead, delete and recreate the instructions from scratch, taking note of which data table addresses are configured in the original instructions before deleting them.
These may not be present at all, or you may not understand what I'm explaining. If you have any questions on this then feel free to ask us.
Also, the 3 stepper modules - these, I'm guessing, are local 1746-HSTP1 stepper modules. If so, they are compatible with all of the SLC processors. Either way, their motion profiles execute independent to the processor scan cycle and so the processor used is not so important, aside from perhaps memory considerations. I do not, at a glance, foresee any issue with them continuing to operate as intended under the SLC 5/05 processor.
For conversion to the likes of the CompactLogix platform, AMCI provide 1769 stepper modules, such as the 3602...
https://www.amci.com/plc-automation-products/3602-compactlogix-motion-controller
Regards,
George