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function [xyz, qual] = PR670measxyz
% PR670measxyz - Make an XYZ measurement with the PR-670.
%
% Syntax:
% [xyz, qual] = PR670measxyz
%
% Output:
% xyz (3x1) - Measured XYZ values.
% qual (scalar) - Measurement quality code. Will be 0 for successful
% measurements, -8 if too little light.
global g_serialPort;
% Check for initialization
if isempty(g_serialPort)
error('Meter has not been initialized.');
end
% Set the response timeout in seconds.
timeout = 30;
% See if we can sync to the source and set sync mode appropriately.
syncFreq = PR670getsyncfreq;
if ~isempty(syncFreq) && syncFreq ~= 0
PR670write('SS1');
else
disp('Warning: Could not sync to source.');
PR670write('SS0');
end
% Make measurement and get the string;
readStr = PR670rawxyz(timeout);
% Extract the returned data.
C = textscan(readStr, '%d,%d,%f,%f,%f');
% Check returned data.
qual = C{1};
switch qual
% Measurement OK
case 0
% Make sure the units look OK.
units = C{2};
assert(units == 0, 'Units not returned as cd/m2');
% Extract the XYZ values.
X = C{3};
Y = C{4};
Z = C{5};
xyz = [X;Y;Z];
% Low light
case -8
xyz = zeros(3,1);
otherwise
error('Bad return code %g from meter', qual);
end
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