Peter SD

CXSupervisor, CJ2M performance issues.

3 posts in this topic


I do not do much Omron work but I do have one large project thats on it's 3rd rev.

I have approx 680 symbols/points that are passed between CX-Supervisor and a CJ2M-CPU15. I am using the USB cooms with the ormon usb driver.

My update rates are very bad. I'm looking at 4 to 8 seconds. 

I have not laid out my points as described in the manual of best pratices because i didn't know it was an issue. 

I have seached for information on this and i hope that i'm missing something.

I could change to a CJ2M- CPU35 and use the ethernet but i don't know how much better that would be. Even USB-2  has a 60Mbs rate but i would guess that the legacy driver would not be that efficient.

What are you people seeing in therms of performance, points and best practices for point alignment?



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Best ignore the theoretical bandwidth of USB-2 (who said it was 2 anyway?). Certainly I remember many early Omron USB ports were just using USB to Serial chipset running at 114Kb. You still see this with the CP1W-CIF41 Ethernet plug-in - still connected to a serial port !

Next thing is that theoretical bandwidth assumes you can process and pump out the messages quickly. For ALL PLCs this is a secondary task so latency means you never get near that. 
Yes, with Ethernet you will easily achieve good performance. Appendix B shows you can expect over 1500 reads a second over Ethernet. 
I realise time and cost are your factors here so your choice, but I would just knuckle down and reorganise the program memory and then recreate the CXS points and will still achieve this. 
Like I said already once this week, FINS memory management is tedious to thanks for EIP tag addressing these days!



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