Rockwell Automation 1771-ASB/E Remote I/O Adapter User Manual - Manual (Page 82)

Questions and Answers D–2
Publication 1771ĆUM001A-US-P - February 2000
Q. I just added a rack to my remote I/O network and my PLC-5
scanner channel autoconfiguration does not recognize it.
Why not?
A. This is typically the result of installation and configuration
problems. Anything from adapter power, wiring and
connections, terminations, improper setting of adapter and
chassis module switches. Use the scanner and adapter status
indicators as a troubleshooting tool. Easy checks include 1.)
installing a known to be good adapter into this chassis, or 2.)
start from scratch by saving the program, clearing the
processor memory by removing the battery, creating an I/O
status file, configuring the scanner channel and
autoconfigure. Sometimes just creating a new I/O status file
works. You could also check this adapter alone with the
scanner without a program in the processor, and without a
module in the chassis. Also, insure that the processor and its
I/O image table suppport the rack address you are adding
and that the rack inhibit bit is not set. Expand the image
table and remove the rack inhibit as necessary.
Q. I am adding a new remote rack to my RIO network. Do I
have to shut my process down to install it?
A. Yes, the processor must be in Program mode to either
manually add or autoconfigure remote I/O devices on the
network.
Q. I just added a rack to my RIO network and my block transfer
data throughput has slowed down considerably. Why?
A. Block transfer throughput is determined by a number of
things, including how many adapters are on the network,
how many block transfer modules are in each chassis,
communication rate and number of block transfer words
being transferred. Refer to your processor user manual to
determine the worst case throughput and recommendations
on how to optimize throughput.
Q. I am adding a new remote rack to my RIO network. Since
this rack is in close proximity to one of my adapters in the
middle of my link, can I wire it directly to that adapter?
A. No, you can’t. Star connections are not allowed on remote
I/O. Daisy-chain or trunkline-dropline configurations are the
only ones permitted.