PLC-5 block transfer error

hi,i have a PLC5 system with something wrong.the cpu was plc-5/80e.with 14 chassis 1771-A3B.the first 13 chassis each has 10 1771-IL 8 analog input module installed,the last chassis has 3 1771-IXE module.the processor use BTR and BTW instruction to read input data and write configuration data.the problem is sometimes the BTR instruction will has a error code with -7 or -9 as shown in the control block data file attached below.if it is due to too many blocks transfered at one time,how to split them.and in the program the programmer seems to write some rungs to deal with this error code.is this error common in the PLC-5 system.and is there any methods to avoid the errors.details about the system and the RSS file is in the attached files.
there are some other questions need you answer:
1.does the channel baud rate has impact in BTR or BTW instruction(like scan time)?
2.in BTR or BTW ,is the rack and slot and module address the starting address,how to determine the last rack and slot and module?

i know there is some experts in this forum,i appreciate you spend a little time to see the program and answer my questions.thanks first.

anyone here

It's the middle of the night on a weekend in the USA, where most of the PLC-5 experts are, so don't be too surprised that you didn't get an answer right away.

Error codes -7 and -9 indicate data corruption or timeouts, so they suggest that there are physical problems with the RIO network media.

This is supported by the Channel Diagnostics (data files N13 and N14, shown in the Channel Configuration -> Channel Status dialog). Channel 1A is in very good condition but Channel 1B has a very large proportion of errors.

The first thing to do is go through the RIO network adapter-by-adapter and look for shorted wires, grounded shields, and corroded or loose terminals. Make sure that there is only one 82 ohm resistor on each end of the network daisy-chain.

Both RIO channels are already running at their maximum speed (230.4 kb/s). While running at a slower data rate sometimes helps improve data reliability, the error rate in this system is so high that a slower data rate is unlikely to help enough to fix the problems.

The block transfer logic in your controller was done in a very unusual manner, using indirect addressing and arrays of control and data blocks. While this may be elegant, it is also complex. I strongly recommend not touching it.

Focus on the physical installation of your RIO cables.