AMT messages: Ind. D/L failed & DCU Queue ovflw


AMT messages: Ind. D/L failed & DCU Queue ovflw

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AMT messages: Ind. D/L failed & DCU Queue ovflw, DL, D/L, Download, Down Load, Overflow, Queue, AMT, Messages, communication


Failure to communicate in C-LAN and SubLan


For the Ind. D/L failed message in AMT, as well as SCU Lost, is from the Host Workstation. It is telling us that there was an error in downloading individual’s information to the SCU.

Lessons Learned Article #4551 has a drawing of a simple INET network, and how it is connected with labels for the names to help with understanding and terminology. Please note the resistors mentioned and make sure your site has these.

Firmware: Check to make sure the same Firmware revision for the INET version you are running is in all the controllers. The DCU7798C is experiencing communication failure. Take a moment to check this as well as from 7798C to the SCU, check the resistors which are shown in the drawing, check the wiring, firmware, etc. That will resolve this failure. If you look closely at the screen shot, it even shows this is a door controller with exceptionally poor communication to the 7798C. It shows the door points. This shows you where to start with the troubleshooting.

Distance: What is the distance between the controllers? I recommend the resistors on long runs or if you have a lot of controllers. If you have more than these two or they are a long way apart, then resistors, yes. If they are 2 meters from each other and it is just these two, then not that critical. The issue appears to be with the CLAN. The pulling down the communication is producing these errors. Check to make sure the wires are protected in conduits and not running along side power or Power-Over-Ethernet, or ballasts. These items can cause interference, which can cause this failure.

Earth Ground: Is the issue on one or between two 7798Cs that are wired the same way. The second 7798C is probably giving the problems. What the issue is no earthgound wire on the three terminal power plug. This is the ground that is used on the CLAN comm circuit. There will be LAN Reconfiguration from ALM, the second 7798c is failing on the CLAN communications.