TM 55-4920-328-13 KEY TO FIGURE 1-23 (Continued). 11.    Oil Flow/Consumption Monitor Unit (Part of 2A2) 12.    Display Control 13.    Function Control 14.    Sensitivity Control 15.    K Factor Pre-set 16.    Fuel Flow Monitor Unit (Part of 2A2) 17.    Display Control 18.    Function Control 19.    Sensitivity Control 20.    K Factor Pre-set 21.    Multi-Channel Vibration Meter 2A3 22.    Vibration Meter 23.    Filter Select Control 24.    Range Control 25.    Mode Control 1.    Speed monitor chassis assembly 2A1.  The speed monitor chassis assembly (1,6, figure 1-23) is a 19- inch    wide,    rack-mounted    unit    4.34    inches    high    and approximately  13.50  inches  deep.    The  digital  frequency counter unit is capable of independently and simultaneously   monitoring   two   channels   of   input   data from    the    gas    producer    and    from    the    power    turbine sections of an engine during a test.  Each channel has a gate time (K factor) variable from 1 millisecond to 9.9999 seconds in 1-millisecond steps.  Prior to operation of the unit, a K factor of 2.381 is manually set into the K factor pre-sets  (5,10).    Ten-millivolt  sensitivity  is  provided  for each  high  impedance  circuit.    Each  unit  consists  of  five main  sections:  power  supply,  input,  gate,  time  base,  and register.  The power supply is provided with a line filter to eliminate  unwanted,  transient  frequencies.    Transformer output in the power supply is rectified to pulsating dc and is subsequently regulated to +5, -15, +15, and +180v dc. The   input   section   receives   input   pulses   and   changes these  signals  to  positive  slope  pulses  in  a  standard  TTL integrated  circuit.    The  gate  section  controls  the  other speed     monitor     chassis     assembly     section     during     a measurement cycle to determine the order and degree in which   each   section   functions.      When   a   start   signal   is received   from   the   time   base   section,   the   gate   section releases a gate on the incoming data to be processed or totalized.  After the gate time (K factor) interval, the gate control  module  reestablishes  the  gate  on  the  input  data. A memory circuit stores the measurement result through a transfer command.  A print command is then released to provide external recording of data.  Upon receipt of a 26.    Cal Adjustment Potentiometer 27.    .Scope Jack 28.    Input Switch 29.    Filter Jack 30.    Sens Adjustment Potentiometer 31.    Fuel   Flow/Oil   Consumption   Signal   Conditioner Panel Assembly 2A9 32.    Oil Quantity Electronic Unit 2A10 33.    Oil Probe Full Potentiometer 34.    Oil Probe Dry Potentiometer 35.    Oil Probe Zero Potentiometer 36.    Receptacle Assembly 2A11 37.    117V AC Receptacle 38.    1-Ampere Fuse 39.    On-Off Switch 40.    Indicator Light stop signal, a sample rate (0.2 to 5.0 seconds, or a hold interval)   begins.      The   sample   rate   is   defined   as   the interval  at  which  point  this  section  gates  the  time  base section    outputs    and    generates    a    reset    command    to prepare for another measurement cycle.  After an interval of   micro-seconds   during   which   all   circuits   have   been reset, the time base gate is released.  The first signal on the  selected  time  base  output  is  the  start  signal  for  the next    measurement    span.        This    section    generates    a reference    frequency    then    divides    this    frequency    into precise    sub-multiples.        The    frequency    generator    is controlled  by  a  stable  quartz  crystal  for  each  precise  K factor.      The   register   section   totalizes   input   signals   to provide instantaneous totals when each pulse is received. Upon   receipt   of   a   transfer   command   from   the   gate section,  integrated  circuit  memory  elements  store  these totals.  Output of the register section is decoded from the BCD   form   to   common   0   to   9-digit   decimal   readout, displayed by neon-glow indicator tubes which illuminate to provide the test technician with output data.  The register section displays totalized events from 0000 to 9999. 2.    Flow/consumption monitor chassis assembly   2A2.      The   flow/consumption   monitor   chassis assembly  (11,16,  figure  1-23)  is  identical  to  the  speed monitor  chassis  assembly  except  for  the  front  and  rear panel   markings.      The   digital   FREQUENCY   COUNTER internal circuitry is the same for each unit; however, the K factor  setting  for  this  unit  differs  from  that  used  in  the speed monitor chassis assembly. 1-38