CG-1280 Rev. N 09/13 - General Dynamics SATCOM Technologies

OverviewPotentiometer PT4 – The analog input circuit contains a zero offset calibrationpotentiometer PT4. Refer to the A/D Calibration section of General DynamicsDocument #CG-0283.Potentiometer PT5 – The analog input circuit contains a gain calibrationpotentiometer PT5. Refer to the A/D Calibration section of General DynamicsDocument #CG-0283.Table 2-6 provides miscellaneous performance specifications that are inherent tothe VCPU board.TABLE 2-6 VCPU PERFORMANCE SPECIFICATIONSDescription Typical Calculated Worst CaseReal Time Clock Accuracy+0.26 to –0.42 Seconds/Day+/- 0.16 Seconds/Day(A TCXO drives this clock)(@ 0-50 Degrees C)NVRAM Battery Backup Shelf Life(external power source off)NVRAM Battery BackupNormal Operation (external powersource operational)Battery Change Period (withoutNVRAM corruption) *24 Months-15 Months(@ 0 Degrees C)>45 Seconds >21 Seconds90% capacity after 10 years due toself discharge(@ 25 Degrees C)* A capacitor keeps the NVRAM powered while the battery is being replaced. This row in the table defines the minimumamount of time that the discharging capacitor will keep the NVRAM powered without the battery present.2.4.1.2 User InterfaceOne of the most striking and advanced features of the 7200 ACU is the userinterface, which combines an 8-inch by 4-inch electroluminescent display with acustom 24-station keypad to provide the most straightforward, powerful, and userfriendlyoperating platform in the industry. As shown in Figure 2-2, the 7200 ACUfront panel layout is uncluttered and offers a logical format for the display ofinformation. For more information on the user interface refer to Section 2.5.1.2.4.1.3 Digital Input/Output Printed-Circuit Board AssemblyThe I/O PCB provides the electrical interface between the ACU and the drivecabinet. In addition, the I/O card serves as the interface between the CPU and theACU rear panel status inputs and control outputs. There are a total of 24 digitalinputs (some inputs are used internally so all 24 are not available through the rearpanel connectors). See table 2-7 for the digital inputs specifications.2-13