RIO Module Compatability

[kevinprior 0]

Hi, I have a number of old PLC 2 systems which communicate via rio using a 1771-ASC adapator module, also on site we have the 1771-ASB module for use on our PLC 5 systems. My question is can the 1771-ASB be used as a striaght swap for the older ASC type? I have been looking on the rockwell website and the main difference I can find is that the ASC will only work using 8 point I/O, but this should not be an issue with the ASB.

[ratcliffe_ic 2]

Yes, I fitted ASB's to a PLC2 system a few years back, replacing the adapters with the thick cables (not sure of the code)

[Ken Roach 194]

The "C" designation way back when was to show that the module shipped with a wiring swingarm, so what you're really seeing is a 1771-AS. 1771-AS can always be replaced by a 1771-ASB module. The chassis may still support only 8-point modules (probably the existing ones are 8-point) but the adapter will work. The reference document for PLC-2 conversions to PLC-5 is RA Knowledgebase Answer ID # 16474. Many of the adaptation rules and guidelines in that document also pertain to ControlLogix conversions. Re-reading your question, it sounds like you might be wanting to use the 1771-ASB as a replacement for 1771-AS but retain the PLC-2 scanner. I am not certain about that; you'd need to call RA Tech Support to find out for sure.

[Gerry 13]

As I recall, the sticker on the module said 1771-ASC and designated the module only. If you ordered catalog no. 1771-AS, you got the module with the swing-arm. Initially, the ASB was 1771-AS/B (as in AS rev B), soon shortened to 1771-ASB and then confused by 1771-ASB rev C. I think the difference between the 1772-SD and 1772-SD2 was support for complementary I/O (??)

[kevinprior 0]

Thanks for all your help, The main reason was that we keep one type in the stores and not the other, so this has saved us keeping both.