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9
2.2.5 Main Circuit Board
The Main Printed Circuit Board (Figure 4) is the central part of the design. It includes a
microcontroller core that implements main logic and provides calculating functions. A
communication circuit provides the interface for the redundant communication network
(RCN), which is how ACE2 receives and transmits data to the ALCMS vault computer. It
contains a fiber optic interface connection for the Current Voltage Monitor (CVM), optional
Insulation Resistance Monitoring System (IRMS), and an RS-232 local configuration
interface. The watchdog jumper (J2) is used to select whether the watchdog timer is On or
Off. Connecting pins 1 and 2 enables the watchdog timer. Connecting pins 2 and 3 disables
watchdog timer, and removing the jumper also disables watchdog timer. The normal setting
for the watchdog timer is On. The watchdog timer should only be set by qualified ADB Airfield
Solutions personnel. The reset switch (SW1) is used during the design and test phase, and
has no application for the user. The keypad switches and an LCD connector provides a
Graphic User Interface (GUI) for local control and monitoring for all controllable functions.
The display is connected to the main board by a ribbon cable. The two-position DIP switch
(SW2), is not currently used, but allows for future upgrades. The DIP switch must remain
with both selectors in the On position for proper operation. The Power Supply circuitry
provides all ACE2 equipment with a regulated and isolated power source.
The Power Supply circuitry can be turned On and Off via the main power switch in the lower
right corner of Figure 4.
Figure 4:
ACE2 Main Circuit Board
1. Ribbon connector to
display board
3. SW1
5. SW7
7. Relay Fuses
2. Main PCB
4. SW2
6. RY7
Table 1:
Main Board Description
Feature
Function Description
Ribbon connector to
display board
Main PCB
SW1
Reset switch - Press to reset the processor
1
2
3
4
5
6
7