classdef OptPowerMeter8153A < handle

    % Code for HEWLETT-PACKARD 8153A Optical Power Meter (2-channel).
    % https://www.artisantg.com/info/Agilent_8153A_Manual.pdf?srsltid=AfmBOoqTe38sbGRNHUFXjw5uO6Br7I7aSfgAdRpx-hVvM4sTIhFYyD5x
    % PAGE 166++

    % Typical usage:
    %   pm = HPPowerMeter8153A( ...
    %       'active',        [false true], ...
    %       'wavelength_nm', [1550 1310] );
    %
    %   pm.setWavelength([1550 1310]);   % only CH2 is modified
    %   p = pm.readPower();              % reads only active channels


    properties (Access = public)
        active        logical = [true true]      % channel enable
        wavelength_nm double  = [1550 1550]      % per-channel wavelength [nm]
        power_dBm     double  = [NaN NaN]        % last read power
        offset_dB double      = [0 0]    % per-channel power offset [dB]
        avgTime_s double        = [0.2 0.2];
    end

    properties (Constant)
        avgTime_min_s = 0.02      % 20 ms
        avgTime_max_s = 3600      % 1 hour
    end

    properties (Access = protected)
        visaAddress string = "GPIB1::22::INSTR"
        numChannels double = 2
    end

    methods
        function obj = OptPowerMeter8153A(options)
            arguments
                options.visaAddress string = "GPIB1::22::INSTR"
                options.active logical = [true true]
                options.wavelength_nm double = [1550 1550]
            end

            fn = fieldnames(options);
            for k = 1:numel(fn)
                obj.(fn{k}) = options.(fn{k});
            end

            assert(numel(obj.active)==obj.numChannels)
            assert(numel(obj.wavelength_nm)==obj.numChannels)

            v = obj.connect();
            writeline(v,"*IDN?");
            disp(readline(v));
            pause(0.1);
            delete(v);
            pause(0.1);

            obj.setWavelength(obj.wavelength_nm);
        end

        function setWavelength(obj, lambda_nm)
            if nargin > 1
                obj.wavelength_nm = lambda_nm;
            end

            v = obj.connect();
            for ch = 1:obj.numChannels
                if obj.active(ch)
                    writeline(v, ...
                        sprintf("SENS%d:POW:WAVE %gNM", ch, obj.wavelength_nm(ch)));
                end
            end
            pause(0.1);
            delete(v);
            pause(0.1);
        end

        function p = readPower(obj)
            v = obj.connect();
            for ch = 1:obj.numChannels
                if obj.active(ch)
                    writeline(v, sprintf("READ%d:POW?", ch));
                    obj.power_dBm(ch) = str2double(readline(v));
                else
                    obj.power_dBm(ch) = NaN;
                end
            end
            delete(v);
            p = obj.power_dBm;
        end

        function setOffsetCorrection(obj, offset_dB)
            obj.offset_dB = offset_dB;

            v = obj.connect();
            for ch = 1:obj.numChannels
                if obj.active(ch)
                    writeline(v, ...
                        sprintf("SENS%d:CORR:LOSS:INP:MAGN %gDB", ch, obj.offset_dB(ch)));
                end
            end
            delete(v);
        end

        function offset_dB = getOffsetCorrection(obj)
            v = obj.connect();
            offset_dB = NaN(1,obj.numChannels);
            for ch = 1:obj.numChannels
                if obj.active(ch)
                    writeline(v, sprintf("SENS%d:CORR:LOSS:INP:MAGN?", ch));
                    offset_dB(ch) = str2double(readline(v));
                end
            end
            delete(v);
            obj.offset_dB = offset_dB;
        end

        function setAvgTime(obj, avgTime_s)

            if any(avgTime_s < obj.avgTime_min_s) || any(avgTime_s > obj.avgTime_max_s)

                oldv = avgTime_s;

                avgTime_s = max(avgTime_s, obj.avgTime_min_s);
                avgTime_s = min(avgTime_s, obj.avgTime_max_s);

                fprintf('[HPPowerMeter8153A] Averaging time clipped:\n');
                for ch = 1:obj.numChannels
                    if oldv(ch) ~= avgTime_s(ch)
                        fprintf('  CH%d: %.3g s  →  %.3g s  (allowed %.3g … %.3g s)\n', ...
                            ch, oldv(ch), avgTime_s(ch), ...
                            obj.avgTime_min_s, obj.avgTime_max_s);
                    end
                end
            end

            obj.avgTime_s = avgTime_s;

            v = obj.connect();
            for ch = 1:obj.numChannels
                if obj.active(ch) && ~isnan(obj.avgTime_s(ch))
                    writeline(v, ...
                        sprintf("SENS%d:POW:ATIME %g", ch, obj.avgTime_s(ch)));
                end
            end
            delete(v);
        end

        function avgTime_s = getAvgTime(obj)
            v = obj.connect();
            avgTime_s = NaN(1,obj.numChannels);
            for ch = 1:obj.numChannels
                if obj.active(ch)
                    writeline(v, sprintf("SENS%d:POW:ATIME?", ch));
                    avgTime_s(ch) = str2double(readline(v));
                end
            end
            delete(v);
            obj.avgTime_s = avgTime_s;
        end

    end

    methods (Access = protected)
        function v = connect(obj)
            v = visadev(obj.visaAddress);
        end
    end
end