Harris Atlas DVL400, Technical Manual

Page: 111 / 180

2/25/03 888-2473-001 4-11
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
ATLAS Series™
Transmitter power will be controlled by the analogue ALC (Automatic Level
Control) voltage sent over a discrete line on the System Control Cable to all of the
PA modules (normally the ALC value is sent over the CAN bus to control
transmitter power).
4.3.5.3.1 Manual Switching
There are 3 momentary switches on the Main Controller board which are primarily
for use in a life support mode when the micro module has failed and the GUI is
therefore not available. These switches are for:
•
Micro RESET, S2
•
Drive Chain Select, S4 (only active in optional dual drive systems). This
switch is labeled RF_CH_ASEL/BSEL_SW.
•
Pump Select, S5. This switch is labeled PUMP_A/B_SEL_SW. This will
select the optional alternate coolant pump in the pump module.
These switches can be used at any time to switch to the alternate drive chain or
coolant pump but are meant for use during a life support mode when the GUI is not
operational. Under normal operating conditions, the GUI or a remote control should
be used to switch pumps. Also keep in mind that drive switching and pump switching
are both automatic functions should there be a loss of drive or coolant flow.
4.3.5.4 Manual RF MUTE
The Main Controller has a toggle switch, S3 which can be used to mute the
transmitter RF output without shutting it off. This switch is primarily used for initial
turn on and troubleshooting but can be used for any purpose which requires the RF
output to be muted. When activated, the GUI will indicate an RF MUTE is present.
4.3.6 External I/O Board
The primary function of the External I/O Board is exactly as its name implies. It is
the interface between the internal transmitter control system and all external or
peripheral devices. Input/Output or I/O ports on the External I/O Board include:
a.
System Control Bus connection to the Main Controller which includes the
CAN bus and parallel control lines.
b.
External I/O Control Cable which connects to the Main Controller. This cable
has an RS-232 connection and several discrete remote control and status lines
which will be used in the event of a failure of the CAN bus. These remote
control and status lines include: