TM-9-1200-215-34&P Technical Manual for M109 Automatic Fire Control System (AFCS) Download
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TM 9–1200–215–34&P 1–6 Section II – EQUIPMENT DESCRIPTION AND DA TA Page Page Equipment Characteristics, Capabilities, and Features 1–6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Location and Description of Major Components 1–8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Differences Between Models 1–13 . . . . . . . . . . . . . . . Equipment Data 1–13 . . . . . . . . . . . . . . . . . . . . . . . . . . Equipment Configuration 1–14 . . . . . . . . . . . . . . . . . . 1–15. EQUIPMENT CHARACTERISTICS, CAP ABILITIES, AND FEATURES a. The Automatic Fire Control System (AFCS) components interface together with an on–board vehicle position sensing system and hydraulic servo valves to automatically lay gun position. AFCS components include: D AFCS Computer Unit (ACU) D Display Unit (DU) D Vehicle Motion Sensor (VMS) Modem D Power Conditioning Unit (PCU) (1) The AFCS Computer Unit (ACU) receives vehicle position data from the on–board positioning system for ballistic computations, weapons control, and calculates distance and direction to the target location entered from the Display Unit (DU). Using stored ballistic data, the ACU calculates appropriate gun tube elevation to reach the target. Elevation and azimuth commands are sent to the weapon’s hydraulics system to adjust gun tube direction and elevation. The ACU automatically performs radio interface functions for the system. It controls radios, radio network interface, intercom interface, and composition/decomposition of messages. It is the digital processing device for the DU, interfaces with the on–board vehicle positioning system, and contains the embedded trainer controller for simulating navigation and gun laying missions. (2) The Display Unit (DU) is the primary man–machine interface and displays system status, navigation data, gun tube position, ammunition inventory, and test/diagnostic messages. A menu driven display provides prompts for data entry using a numeric keypad. (3) The Prognostic/Diagnostic Interface Unit (PDIU) performs prognostic and diagnostic functions on the weapon system. The PDIU tests, detects faults, and fault isolates Line Replaceable Units (LRUs) in the Electrical System, Automatic Fire Control System (AFCS), Vehicle Hydraulic System, and Gun Position System. (4) The Vehicle Motion Sensor (VMS) Modem provides a means to transmit digital vehicle motion data from the motion sensor location in the hull, through the vehicle slip rings, to the ACU location in the cab. (5) The Power Conditioning Unit (PCU) protects all electronic digital subsystems from power transients, compensates for voltage drops and spikes, and continuously monitors system circuits for vehicle and battery status. b. The Prognostic/Diagnostic Interface Unit (PDIU) performs prognostic and diagnostic functions on a weapon system. The PDIU tests, detects faults, and fault isolates Line Replaceable Units (LRUs) in the Electrical System, Automatic Fire Control System (AFCS), Vehicle Hydraulic System, and Gun Position System.