Datatrac 400 Operations Manual - Aeroflex

Aeroflex Operation ManualByteDescription0 Channel # (1, 2, 3, or 4)1 Label2 Data 1 (bits 9-16)3 Data 2 (bits 17-24)4 Data 3 (bits 25-32)5 Time 06 Time 17 Time 2Label, Data 1, Data 2, and Data 3 are the four bytes of the ARINC word received. The bit order of thelabel byte is already swapped to read directly as the octal ARINC label.Time 0, Time 1, and Time 2 are the BCD encoded values for the relative time the label was received.Time 0 is the least significant byte, Time 2 is the most significant byte. The timer is a countdowntimer such that subsequent label receipts will have a smaller time value. The range is 999,999 ms to000,000 ms, or roughly 17 minutes. Upon reaching a time value of 000000, the timer will wraparound to 999999 and resume counting down. All values are transmitted as binary numbers, not theirASCII representation.When the receiver is operating in the ALL mode, all incoming labels will be downloaded to the RS-232C port. When the receiver is operating in SELECT mode, only the selected labels will bedownloaded.NOTE: Due to the finite baud rate (9600), the user must be careful not to overload the RS-232C port with real-time data at an average rate that exceeds the capacity of the bus. Sincethere are eight bytes per record, it takes the RS-232C port approximately 9 ms per record.Thus for a single label, a transmit interval less than 9 ms would cause an RS-232 overflowresulting in incorrect data being downloaded.3.2.4 RECEIVE DATA DISPLAY LINES SELECTIONThis setup line allows the user to customize the receiver display screen when multiple channels arebeing displayed. The user may select the number of labels (one label per line) to be displayed foreach channel. The size of the display windows on the real time screen are set automatically by theunit each time a receive or transmit channel is enabled (or disabled). The default values are (as afunction of the number of channels enabled):1 channel on - 14 lines per channel2 channels on - 6 lines per channel (or 12 lines total)3 channels on - 3 lines per channel (or 9 lines total)4 channels on - 2 lines per channel (or 8 lines total)DATATRAC 400 – REV 0 – PAGE 3-19