TM-9-1200-215-34-P
AUTOMATIC FIRE CONTROL SYSTEM (AFCS)
TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL
FEBRUARY 1999
TM-9-1200-215-34-P - Page 40 of 266
TM 9–1200–215–34&P
2–5
(5)
Discrete I/O Circuit Card Assembly (CCA). The Discrete I/O CCA consists of analog and digital circuitry
that supports key communications protocols and formats used by the ACU to communicate with other AFCS
hardware. The links provided by the Discrete I/O CCA include:
Digital and discrete signal communications with the Display Unit (DU)
Digital signal communications with the Dynamic Reference Unit (DRU)
Digital signal communications with the Cab–Side VMS Modem
Discrete communications with the Power Conditioning Unit (PCU) and Vehicle Intercom System (VIS)
(6)
1553 Circuit Card Assembly (CCA). Interconnection of the ACU with the remainder of the AFCS is
accomplished through the 1553 bus system. The 1553 CCA provides the interface between the ACU and the
1553 bus.
(7)
Tactical Communications Interface Module (TCIM) (CCA).
The Tactical Communications Interface
Module CCA allows direct connection between the ACU single–board computer CCA and the SINCGARS via the
SCSI port of the computer CCA.
(8)
Backplane. The backplane of the ACU provides connectors for mating with the CCAs, and distributes
signals and power among the CCAs. The chassis card slot allocations for the ACU component modules are
depicted in Figure 2–2.
A3
A5
A6
DISCRETE I/O
A7
SERVO I/F CCA
BACKPLANE CONNECTOR (POWER)
POWER SUPPLY MODULE
CPU CCA
TCIM CCA
1553 I/F CCA
A1
(J1)
(J8)
(J2)
(J5)
(J10)
(J11)
(J12)
(J13)
Figure 2–2.
ACU Backplane Connectors
(9)
Solenoid Relay. The Solenoid Relay provides power to the Hydraulic Solenoid Valve and the Bypass
Valve. The Hydraulic
Solenoid Valve applies vehicle hydraulic pressure to the Azimuth and Elevation Servo
Valves when adjusting the position of the weapon. The bypass valve allows hydraulic fluid to flow around the
hydraulic motor when the hydraulic system is not pressurized. This allows the weapon to be hand cranked into
position in the event the AFCS is inoperative.
Change 1
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