TM 1-1510-218-10 2-50 NOTE Pressing  the  EXCEEDENCE  ERASE  switch for   0.2   seconds   or   longer   will   cause   all events    to    be    erased    from    non-volatile memory in all engine instruments.  There is no  provision  for  erasing  individual  events from individual system gauges.  The    ITT    gauges    are    each    protected    by    a 1.0-ampere  circuit  breaker  located  on  the  pilot’s  left subpanel, placarded  ITT TEMP #1 and  ITT TEMP #2, Figure 2-8, Sheets 2 and 3. b.  Percentage   Engine   Torquemeters.       The indicator displays the measured torque concurrently in a  1  alphabetic,  3½  numeric  character  digital  display, and a 1-segment bar graph display. The indicator has a digital display range of 0 to 123%.  The bar graph display range is 0 to 120%. The digital display is accurate to 1% and the bar graph is accurate to one-half the segment resolution in each dial scale range. The  display  will  contain  dashes  (----) when the measured  torque  is  greater  than  124%.    The  dashes will  be  prefixed  with  an  "F"  if  an  EEPROM  failure  has been  detected  and  with  an  "E"  if  an  event  has  been stored and not played back.  The "F" display shall take precedence over the "E" display. The indicator has a BIT test for the LCD display, ROM (program memory), RAM (volatile data memory), EEPROM  (non-volatile  memory),  and  the  signal  input path.    The  display  BIT  will  consist  of  displaying  all active LCD segments for three seconds on power up.   If the RAM or ROM BIT fails the indicator display shall be  blanked.    If  the  input  signal   fails  BIT  the  indicator shall  display  "0"  on  both  the  digital  and  bar  graph displays.    BIT  failures  are  NOT  stored  in  EEPROM.   Once  the  power  is  cycled  the  display  is  not  affected unless the failure is again detected. Exceedence  events  will  be  stored  in  EEPROM memory.  Each event record will consist of two 16-bit words.      One   word   will   contain   the   peak   torque measured  during  the  event  and  the  other  word  shall contain the event duration in seconds.  A maximum of 50  events  shall  be  recorded.    If  more  than  50  events are  recorded,  only  50  will  be  stored.    As  new  events are  recorded,  the  oldest  events  shall  be  discarded.   The indicator will prefix the digital display with an "E" when an event is being or has been recorded and not played back. The   indicator   digital   display   will   start   flashing whenever    indicated    torque    exceeds    100%.        The flashing shall cease and digital torque display shall be prefixed with an "E" when the time/torque combination is   exceeded   and   the   indicator   begins   recording   an exceedance. Event  display  will  take  precedence  over  normal digital  display.    The  bar  graph  will  continue  to  display current   engine   torque   data.      The   event   display   is initiated   by   pressing   the    EXCEEDENCE   DISPLAY switch  for  0.2  seconds  or  longer.    The  event  display will consist of the following: (1)   The  event  number  will  be  displayed  for 2 seconds. (2)   The  event  peak  torque  percentage  value will be displayed for 2 seconds. (3)   The  event  duration,  in  seconds,  will  be displayed for 2 seconds. All  three  data  items  displayed  during  playback will  be  prefixed  with  a  "P"  unless  an  EEPROM  BIT failure has been detected in which case the display will be prefixed with an "F". Once   an   event   playback   sequence   has   been performed, the "E" prefixed to the digital display shall be   removed.      All   event   data   is   still   available   for playback  until  the  data  is  erased.    The  display  will  be prefixed with an "E" again on the next power up cycle if the old data has not been erased or if another event is recorded. NOTE Pressing  the  EXCEEDENCE  ERASE  switch for   0.2   seconds   or   longer   will   cause   all events    to    be    erased    from    non-volatile memory.  There is no provision for erasing individual events.  The engine torquemeter gauges are protected by 0.5-ampere    circuit    breakers,    placarded    TORQUE METER #1   and  #2,  located  on  the  overhead  circuit breaker panel. c.   Turbine Tachometers.  The indicator displays    the    measured    N₁    concurrently    in    a    1 alphabetic, 3½ numeric character digital display and a 39-segment bar graph for erasing individual events. The  indicator  has  a  digital  display  range of 0 to 110.0%   RPM   while   displaying   current   N₁  and  0  to 199.9%  RPM  while  displaying  exceedence  N₁.    The bar graph display range is 0 to 150.0% RPM. The   digital   display   shall   contain   dashes   (----) when  the  measured  N₁ is greater than 110.0% RPM.