Rio scan times

I have a printing machine running RIO with ASB modules in each section talking to a SN series B card in a SLC 500. I converted the Panelview Standard to Panelview Plus Ethernet and use a NET-ENI to interface with the Processor.
I have an encoder on the first section of the machine going to a HSCE set to ring counter reset at 2048 which is one revolution of the machine. I have a proximity switch mounted on the other sections toggling a bit through a one shot each revolution to determine there reference to the first section. Theses are mounted on the Print Cylinder that can be moved in either direction to line up the print. I cant mount an encoder directly to them since the motors spin and are powered through brush rings. I was hoping to "freeze" the encoder count each time the proximity was made so I could see the difference in the amount of travel when the print cylinder was moved.
It all works my only problem is the display varies back and fort up to an inch
(I am running the HSCE input through an SCP instruction 0-2048 = 0-66")
Could this be a communications delay issue between the ASB and the SLC.
Any Ideas would be appreciated, Thanks

You might want to try to access the data directly in the M files.
This explains it in more detail.http://literature.rockwellautomation.com/idc/groups/literature/documents/um/1747-um013_-en-p.pdf.
From the manual:
"If you are using an SLC 5/02 processor, M file data
cannot be directly monitored. To monitor M files,
you must move the M file words into an SLC file that
can be monitored, e.g., an integer “N” file. SLC 5/03
or later processors allow you to monitor M files
directly. However, do not address M file bits more
than necessary throughout your application program.
The processor accesses M files like immediate I/O.
Therefore, excessive addressing of M files can greatly
increase SLC processor scan time. For more
information on M files, refer to Appendix B."

Thank you I will read up on this I am using a 532E Processor. Do you think it would make a difference if I put the proximity switch on an input on the SLC instead of the remote I/O

Yes, That will help.
What is the catalog number of the high speed counter card?
You might be able to use an input on the HSC card.

This is a 1746 HSCE Series A
My logic in the program uses the input from this card directly into a SCP
When a proximity on any of the other 3 sections flags through a one shot I send the output to a display on the screen for that particular section.

You can also set the speed of your remote IO to 256K baud (usually its 57K). That may yield a better update time.

I will reset the SN and ASB units to the higher Baud rate to test, I will also see if running the extra wire from each section for the proximity input to the main cabinet SLC makes a difference. I need to read up more on the HSCE to see if I can accomplish what I need differently with it. Thanks All