Specifications

Doc Number: VIS-ANA-VER-01001-9002
Date: 27 May 2004
Issue: 5.0
Page: 27 of 80
Author: J. Delgadillo
Controls Preliminary Design Report Issue 5.doc
Figure 4.2.2.1.D - AZ/ALT PDU CCU BLOCK DIAGRAM
4.2.4.7 AZ/ALT Control Board
Although the Control board physically resides in the CCU, it is totally microprocessor and
CCU independent. It provides an interface between the CCU computer (for monitoring
purposes only) and external motor disabling connections to the mount structure.
The Control board receives rate commands and enable requests from the LCU, MCU or the
PMU and generates directional enables, axis rates, brake release commands and status/faults
to all control units. The Control board also contains the acceleration/deceleration limiting
circuitry and the soft-stop circuitry that enables a controlled deceleration before applying the
brakes (when not in an emergency stop condition).