Specifications

Doc Number: VIS-ANA-VER-01001-9002
Date: 27 May 2004
Issue: 5.0
Page: 16 of 80
Author: J. Delgadillo
Controls Preliminary Design Report Issue 5.doc
Connectorized interconnection cabling will be provided for the MCS, including the cabling
for the LCUs (AZ, ALT and CASS) (AD01 11.1.1 spec). The interconnection cables, as well
as the hook-up cables (internal to the subassemblies) will be halogen free (AD07 4.3.1.3.1
spec), and in conformance with the applicable DIN, VDE, IEC standards for cable
construction and tests. The signal cables will be colour coded per DIN 47100 (AD07
4.3.1.3.1 spec). The power cable conductors (1.5 mm
2
- 6 mm
2
) will have black colour
insulation marked with white numbers which identif ies the conductor. The mains power
hook up cables inside the subassemblies will be colour coded per DIN VDE 0293 as follows:
φ A Black
φ B Brown
φ C Black
3φN Blue
3φG Yellow/Green
1φL Brown
1φN Blue
G Yellow/Green
The AZ/ALT and the CASS PDU signal and low power connectors will be the MIL-C-38999,
Series III type which offers the highest performance capabilities. The high power connectors
will be the MIL-C-5015 type. EMI/RFI connector back-shells will be used (Mil Standard
M85049) to provide excellent grounding of the cables’ overall shield. This will provide
excellent attenuation of any radiated emissions.
4.2.1 Mount Control System Control Loops/Points of Control
Figure 4.2.B, VISTA Control Loop Block Diagram, shows in block diagram format, the
VISTA nested loops: Position, Rate and Current (Torque). The block diagram also depicts
the three points of control for the mount: LCU, MCU and PMU. Since the MCU and PMU
are not part of the system being delivered to meet the requirements of AD01 and AD02, these
units can be considered test equipment.
As can be seen from Figure 4.2.B, when the MCU is in control, it issues Position Commands,
when the LCU is in control it issues Velocity Commands, and when the PMU is in control it
issues Velocity Commands.
By default, the LCUs will be offered control of the system. Once a unit takes control, the off-
line units cannot acquire control until the on-line unit relinquishes control. A manual,
mechanical switch in the AZ/ALT and in the CASS PDU will be used to Activate (allow the
LCUs to take control of the mount) the LCUs. Once in control of their respective axis, LCU
motor enables/disables and rate demands can be successfully issued independently. When
the switch is placed to the alternate position, the LCUs relinquish control of the mount.