SL8500 - Opposite H-Bot on a Rail Can Cause Issues

Asset ID:	1-75-1665829.1
Update Date:	2017-09-21
Keywords:

Solution Type Troubleshooting Sure

Solution 1665829.1 : SL8500 - Opposite H-Bot on a Rail Can Cause Issues

Applies to:

Sun StorageTek SL8500 Modular Library System - Version All Versions and later
Information in this document applies to any platform.

Purpose

Opposite H-Bot on a Rail Can Cause Issues.

Troubleshooting Steps

When troubleshooting repeated bot failures in the same location it is possible that the non-failing H-Bot on a rail may have a communication problem that can affect the failing bot. Particularly for 1301 errors (response timeouts). On any repeat call you need to see if the failure is the same as the previous bot's failure. If it is different then the new bot may be at fault. If it is the same it is best to swap the failing bot with a bot from another rail and put the new bot in that location. If time permits the bot on the same rail on the opposite side of the machine should be swapped to a rail not involved with the previously recommended swap.

Remember to always swap bots vertically on the same side of the SL8500. Swapping bots from side-to-side can confuse the controller and require multiple rail resets or reboots to recover from.

Assuming H-Bot "D" on Rail2 in the left diagram below has repeated failures, you could remove "D" and put the new bot "N" into the SL8500 and move the other bots as shown in the right diagram:

    L R       L R

R1 A B    A N
R2 C D    E B
R3 E F    C F
R4 G H   G H

Moving the bots in this manner will help isolate the problem.

Always check/replace the terminators when troubleshooting repeating failures in the same location. It has been my experience that the terminator on the opposite side of a failure is often at fault. The most common issue is intermittent connections due to loose push-on connectors on the terminators. In most cases these can be tightened by squeezing with a pair of pliers.

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