User's Manual

3-5

System Diagnostic Controller

This diagnostic controller is composed of a Z-80 microprocessor and its

supporting logic. The diagnostic controller performs the following:

¥ Controls the power-up sequencing of modules

¥ Monitors the 9A656-04 input and output power parameters

¥ Keeps watch over the main host processor

¥ Monitors the temperature

¥ Controls the SMB LANVIEW diagnostic LED

Although the diagnostic controller and the main host processor can operate

independently of each other if needed, they exchange information about each

otherÕs status and overall module condition. The information gathered by the

diagnostic controller is available to the network manager via Local/Remote

Management and the LCD located on the environmental module. The 9A656-04

has been designed so that in the event of a diagnostic controller fault, the modules

continue to function.

DC/DC Converter

The DC/DC converter converts the 48 Vdc on the system power bus to the

necessary operating voltages for its host network services module. The diagnostic

controller controls the operation of the dc/dc converter.