function ens = rdadens(ens)
% ens = rdadens(ens)  Reads one ensemble of ADCP data into structure ens.
% This script reads from a packed binary file of ADCP data.  The
% format is given in the RDI Technical Manual, P.N. 951-6046-00 .
% Units are converted to meters.
% ens must contain the file id of the (opened) file as ens.fidin .
   fid = ens.fidin;
   ens.id1=fread( fid,1,'uchar' ); % Two ID bytes, both = 127
   ens.id2=fread( fid, 1, 'uchar' );
   if ens.id1 ~= 127 | ens.id2 ~= 127
      '****** ERROR READING ID BYTES ******'
   end
   ens.id3=fread( fid, 2, 'uchar' ); % Is this a transect number?
   junk1 = fread( fid, 1, 'uchar' );
   ens.NDT = fread( fid, 1, 'uchar' ); % Number of data blocks.
   ens.doffset = fread( fid, ens.NDT, 'short' ); % Offsets

   % In principle the preceeding data permit a generalized unpacking
   % procedure.  What follows assumes a particular configuration of
   % data, however:  velocity data (type 1), correlation magnitudes 
   % (type 2), echo intensities (type 3), percent-good data (type 4), 
   % and bottom-track data (type 5).

   ens.fid = fread( fid, 1, 'short' );
   ens.fv = fread( fid, 1, 'uchar' );
   ens.fr = fread( fid, 1, 'uchar' );
   ens.syscfg = fread( fid, 1, 'short' );
   ens.pd = fread( fid, 1, 'uchar' );
   junk1 = fread( fid, 1, 'uchar' );
   ens.nbm = fread( fid, 1, 'uchar' );
   ens.WN = fread( fid, 1, 'uchar' );
   ens.WP = fread( fid, 1, 'short' );
   ens.WS = fread( fid, 1, 'short' )/100.; % Depth cell length.
   ens.WF = fread( fid, 1, 'short' )/100.; % Blank after transmit
   					     % distance.
   ens.WM = fread( fid, 1, 'uchar' );
   ens.WC = fread( fid, 1, 'uchar' );
   ens.ncr = fread( fid, 1, 'uchar' ); % No. of code repetitions.
   ens.WG = fread( fid, 1, 'uchar' );
   ens.WE = fread( fid, 1, 'short' )/1000.; % Velocity-error limit.
   ens.tppmn = fread( fid, 1, 'uchar' ); % Time between ping groups.
   ens.tppsc = fread( fid, 1, 'uchar' );
   ens.tpphd = fread( fid, 1, 'uchar' );
   ens.EX = fread( fid, 1, 'uchar' ); 
   ens.EA = fread( fid, 1, 'short' )/100.; % Heading-alignment
   					     % correction.
   ens.EB = fread( fid, 1, 'short' )/100.; % Heading bias (Mag
   					     % field).
   ens.EZ = fread( fid, 1, 'uchar' ); % Sensors to be used.
   ens.SA = fread( fid, 1, 'uchar' ); % Sensors available.
   ens.dis1 = fread( fid, 1, 'short' )/100.; % Distance to middle of first
					       % depth cell, measured
					       % from the transducer head.
   ens.WT = fread( fid, 1, 'short' )/100.; % Transmit pulse length.
   ens.WL = fread( fid, 1, 'uchar' ); % Starting and ending cell
   ens.WP = fread( fid, 1, 'uchar' ); % numbers for reference layer.
   ens.WA = fread( fid, 1, 'uchar' ); % False-target threshold.
   junk1 = fread( fid, 1, 'uchar' );
   ens.LagD = fread( fid, 1, 'short' )/100.; % Distance between pulse
					       % (=code?) repetitions.
   %***** Start variable leader data. *****
   ens.VID = fread( fid, 1, 'short' );
   if ens.VID ~= 128
      '****** ERROR READING VARIABLE LEADER DATA ******'
   end
   ens.ENS = fread( fid, 1, 'short' );
   ens.RTCyr = fread( fid, 1, 'uchar' ); % Real-Time Clock.
   ens.RTCmo = fread( fid, 1, 'uchar' );
   ens.RTCdy = fread( fid, 1, 'uchar' );
   ens.RTChr = fread( fid, 1, 'uchar' );
   ens.RTCmn = fread( fid, 1, 'uchar' );
   ens.RTCsc = fread( fid, 1, 'uchar' );
   ens.RTChd = fread( fid, 1, 'uchar' );
   ens.ENSMSB = fread( fid, 1, 'uchar' );
   ens.BIT = fread( fid, 1, 'short' );
   ens.EC = fread( fid, 1, 'short' ); % Speed of sound.
   ens.ED = fread( fid, 1, 'short' )/10.; % Transducer depth (in
                                        % decimeters??!!).
   ens.EH = fread( fid, 1, 'short' )/100.; % Heading angle
   ens.EP = fread( fid, 1, 'short' )/100.; % Pitch angle.
   ens.ER = fread( fid, 1, 'short' )/100.; % Roll angle.
   ens.ES = fread( fid, 1, 'short' ); % Salinity (ppt)
   ens.ET = fread( fid, 1, 'short' )/100.; % Temperature.
   ens.MPTmm = fread( fid, 1, 'uchar' );
   ens.MPTss = fread( fid, 1, 'uchar' );
   ens.MPThh = fread( fid, 1, 'uchar' );
   ens.Hsd = fread( fid, 1, 'uchar' ); % Heading standard deviation.
   ens.Psd = fread( fid, 1, 'uchar' )/10.; % Pitch std. dev.
   ens.Rsd = fread( fid, 1, 'uchar' )/10.; % Roll std. dev.
   ens.ADC0 = fread( fid, 1, 'uchar' );
   ens.ADC1 = fread( fid, 1, 'uchar' );
   ens.ADC2 = fread( fid, 1, 'uchar' );
   ens.ADC3 = fread( fid, 1, 'uchar' );
   ens.ADC4 = fread( fid, 1, 'uchar' );
   ens.ADC5 = fread( fid, 1, 'uchar' );
   ens.ADC6 = fread( fid, 1, 'uchar' );
   ens.ADC7 = fread( fid, 1, 'uchar' );
   % Decode the velocity data.
   ens.VELID = fread( fid, 1, 'short' );
   if ens.VELID ~= 1
      '****** ERROR READING VELOCITY DATA ******'
   end
   % Read in velocities, convert from mm/s to m/s.
   ens.vtx=zeros(4,ens.WN);
   for iwn=1:ens.WN
      ens.vtx(1:4,iwn) = fread( fid, 4, 'short' )/1000.;
   end
   % Decode the correlation magnitudes.
   ens.CMID = fread( fid, 1, 'short' );
   if ens.CMID ~= 2
      '****** ERROR READING CORRELATION MAGNITUDES ******'
   end
   ens.cormag = zeros(4,ens.WN);
   for iwn=1:ens.WN
      ens.cormag(1:4,iwn) = fread( fid, 4, 'uchar' );
   end
   % Decode the echo intensities.
   ens.ECHID = fread( fid, 1, 'short' );
   if ens.ECHID ~= 3 
      '****** ERROR READING ECHO INTENSITIES ******'
   end
   ens.echo=zeros(4,ens.WN);
   for iwn=1:ens.WN
      ens.echo(1:4,iwn) = fread( fid, 4, 'uchar' );
   end
   % Decode the percent-good data.
   ens.PCTID = fread( fid, 1, 'short' );
   if ens.PCTID ~= 4
      '****** ERROR READING PERCENT-GOOD DATA ******'
   end
   ens.pctgood=zeros(4,ens.WN);
   for iwn=1:ens.WN
      ens.pctgood=fread( fid, 4, 'uchar' );
   end
   % decode the bottom-track data.
   ens.BTID = fread( fid, 1, 'short' );
   if ens.BTID ~= 6 
      '****** ERROR READING BOTTOM-TRACK DATA ******	'
   end

   ens.BP = fread( fid, 1, 'short' ); 
   ens.BD = fread( fid, 1, 'short' );
   ens.BC = fread( fid, 1, 'uchar' );
   ens.BA = fread( fid, 1, 'uchar' );
   ens.Bpct = fread( fid, 1, 'uchar' );
   ens.BM = fread( fid, 1, 'uchar' );
   ens.BE = fread( fid, 1, 'short' )/1000.; % Max. bottom-track error.
   junk1 = fread( fid, 1, 'short' );
   junk1 = fread( fid, 1, 'short' );
   ens.BTR = fread( fid, 4, 'short' )/100.;
   ens.BTV = fread( fid, 4, 'short' )/1000.;
   ens.BTCM = fread( fid, 4, 'uchar' ); 
   ens.BTEA = fread( fid, 4, 'uchar' );
   ens.BTPG = fread( fid, 4, 'uchar' );
   ens.BLM = fread( fid, 1, 'short' )/10.; % Min. Layer size
   ens.BLN = fread( fid, 1, 'short' )/10.; % Near boundary of
                                              % reference layer.
   ens.BLF = fread( fid, 1, 'short' )/10.; % Far boundary.
   ens.RLV = fread( fid, 4, 'short' )/1000.; % Reference layer
                                               % velocities.
   ens.RLCM = fread( fid, 4, 'uchar' ); % Ref. layer corr. mags
   ens.RLEI = fread( fid, 4, 'uchar' ); % Ref. layer echo intens.
   ens.RLPG = fread( fid, 4, 'uchar' ); % Ref. layer percent. good
   ens.BX = fread( fid, 1, 'short' )/10.; % Max. tracking depth value
   ens.RSSI = fread( fid, 4, 'uchar' );
   ens.RSSIgain = fread( fid, 1, 'uchar' );
   ens.BTRmsb = fread( fid, 4, 'uchar' );
   ens.IRES = fread( fid, 2, 'uchar' );
   ens.CHSUM = fread( fid, 2, 'uchar' );