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rINSTCONTROL/@MyScpiInstrument/MyScpiInstrument.m
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MyScpiInstrument.m
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% Class featuring a specialized framework for instruments supporting SCPI
%
% Undefined/dummy methods:
% queryString(this, cmd)
% writeString(this, cmd)
classdef MyScpiInstrument < MyInstrument
methods (Access = public)
% Extend the functionality of base class method
function addCommand(this, tag, command, varargin)
p = inputParser();
p.KeepUnmatched = true;
addRequired(p, 'command', @ischar);
addParameter(p, 'access', 'rw', @ischar);
addParameter(p, 'format', '%e', @ischar);
addParameter(p, 'value_list', {}, @iscell);
addParameter(p, 'validationFcn', function_handle.empty(), ...
@(x)isa(x, 'function_handle'));
addParameter(p, 'default', 0);
% Command ending for reading
addParameter(p, 'read_ending', '?', @ischar);
% Command ending for writing, e.g. '%10e'
addParameter(p, 'write_ending', '', @ischar);
parse(p, command, varargin{:});
% Create a list of remaining parameters to be supplied to
% the base class method
sub_varargin = struct2namevalue(p.Unmatched);
% Introduce variables for brevity
format = p.Results.format;
write_ending = p.Results.write_ending;
if ismember('format', p.UsingDefaults) && ...
~ismember('write_ending', p.UsingDefaults)
% Extract format specifier and symbol from the write ending
[smb, format] = parseFormat(this, write_ending);
else
% Extract format symbol
smb = parseFormat(this, format);
end
if ismember('b', smb)
% '%b' is a non-MATLAB format specifier that is introduced
% to designate logical variables
format = replace(format, '%b', '%i');
write_ending = replace(write_ending, '%b', '%i');
end
this.CommandList.(tag).format = format;
% Add the full read form of the command, e.g. ':FREQ?'
if contains(p.Results.access, 'r')
read_command = [p.Results.command, p.Results.read_ending];
readFcn = ...
@()sscanf(queryString(this, read_command), format);
sub_varargin = [sub_varargin, {'readFcn', readFcn}];
else
read_command = '';
end
this.CommandList.(tag).read_command = read_command;
% Add the full write form of the command, e.g. ':FREQ %e'
if contains(p.Results.access,'w')
if ismember('write_ending', p.UsingDefaults)
write_command = [p.Results.command, ' ', format];
else
write_command = [p.Results.command, write_ending];
end
writeFcn = ...
@(x)writeString(this, sprintf(write_command, x));
sub_varargin = [sub_varargin, {'writeFcn', writeFcn}];
else
write_command = '';
end
this.CommandList.(tag).write_command = write_command;
% If the value list contains textual values, extend it with
% short forms and add a postprocessing function
value_list = p.Results.value_list;
validationFcn = p.Results.validationFcn;
if ~isempty(value_list)
if any(cellfun(@ischar, value_list))
% Put only unique full-named values in the value list
[long_vl, short_vl] = splitValueList(this, value_list);
value_list = long_vl;
% For validation, use an extended list made of full and
% abbreviated name forms and case-insensitive
% comparison
validationFcn = createScpiListValidationFcn(this, ...
[long_vl, short_vl]);
postSetFcn = createToStdFormFcn(this, tag, long_vl);
sub_varargin = [sub_varargin, ...
{'postSetFcn', postSetFcn}];
end
end
% Assign validation function based on the value format
if isempty(validationFcn)
validationFcn = createArrayValidationFcn(this, smb);
end
sub_varargin = [sub_varargin, { ...
'value_list', value_list, ...
'validationFcn', validationFcn}];
% Assign default based on the format of value
if ~ismember('default', p.UsingDefaults)
default = p.Results.default;
elseif ~isempty(value_list)
default = value_list{1};
else
default = createValidValue(this, smb);
end
sub_varargin = [sub_varargin, {'default', default}];
% Execute the base class method
addCommand@MyInstrument(this, tag, sub_varargin{:});
end
% Redefine the base class method to use a single read operation for
% faster communication
function sync(this)
cns = this.command_names;
ind_r = structfun(@(x) ~isempty(x.read_command), ...
this.CommandList);
read_cns = cns(ind_r); % List of names of readable commands
read_commands = cellfun(...
@(x) this.CommandList.(x).read_command, read_cns,...
'UniformOutput',false);
res_list = queryStrings(this, read_commands{:});
if length(read_cns)==length(res_list)
% Assign outputs to the class properties
for i=1:length(read_cns)
tag = read_cns{i};
val = sscanf(res_list{i}, ...
this.CommandList.(tag).format);
if ~isequal(this.CommandList.(tag).last_value, val)
% Assign value without writing to the instrument
this.CommandWriteEnabled.(tag) = false;
this.(tag) = val;
this.CommandWriteEnabled.(tag) = true;
end
end
else
warning(['Could not read %i out of %i parameters, ',...
'no properties of %s object are updated.'], ...
length(read_commands)-length(res_list), ...
length(read_commands), class(this));
end
end
%% Write/query
% These methods implement handling multiple SCPI commands. Unless
% overloaded, they rely on write/readString methods for
% communication with the device, which particular subclasses must
% implement or inherit separately.
% Write command strings listed in varargin
function writeStrings(this, varargin)
if ~isempty(varargin)
% Concatenate commands and send to the device
cmd_str = join(varargin,';');
cmd_str = cmd_str{1};
writeString(this, cmd_str);
end
end
% Query commands and return the resut as cell array of strings
function res_list = queryStrings(this, varargin)
if ~isempty(varargin)
% Concatenate commands and send to the device
cmd_str = join(varargin,';');
cmd_str = cmd_str{1};
res_str = queryString(this, cmd_str);
% Drop the end-of-the-string symbol and split
res_list = split(deblank(res_str),';');
else
res_list = {};
end
end
end
methods (Access = protected)
%% Misc utility methods
% Split the list of string values into a full-form list and a
% list of abbreviations, where the abbreviated forms are inferred
% based on case. For example, the value that has the full name
% 'AVErage' has the short form 'AVE'.
function [long_vl, short_vl] = splitValueList(~, vl)
long_str_vl = {}; % Full forms of string values
short_vl = {}; % Abbreviated forms of string values
num_vl = {}; % Numeric values
% Iterate over the list of values
for i = 1:length(vl)
% Short forms exist only for string values
if ischar(vl{i})
long_str_vl{end+1} = vl{i}; %#ok<AGROW>
% Add short form
idx = isstrprop(vl{i},'upper');
short_form = vl{i}(idx);
if ~isequal(vl{i}, short_form) && ~isempty(short_form)
short_vl{end+1} = short_form; %#ok<AGROW>
end
else
num_vl{end+1} = vl{i}; %#ok<AGROW>
end
end
% Remove duplicates
short_vl = unique(lower(short_vl));
% Make the list of full forms
long_vl = [num_vl, ...
setdiff(lower(long_str_vl), short_vl, 'stable')];
end
% Create a function that returns the long form of value from
% value_list
function f = createToStdFormFcn(this, cmd, value_list)
function std_val = toStdForm(val)
% Standardization is applicable to char-valued properties
% which have value list
if isempty(value_list) || ~ischar(val)
std_val = val;
return
end
% find matching values
n = length(val);
ismatch = cellfun(@(x) strncmpi(val, x, ...
min([n, length(x)])), value_list);
assert(any(ismatch), ...
sprintf(['%s is not present in the list of values ' ...
'of command %s.'], val, cmd));
% out of the matching values pick the longest
mvals = value_list(ismatch);
n_el = cellfun(@(x) length(x), mvals);
std_val = mvals{n_el==max(n_el)};
end
assert(ismember(cmd, this.command_names), ['''' cmd ...
''' is not an instrument command.'])
f = @toStdForm;
end
% Find the format specifier symbol and options
function [smb, format] = parseFormat(~, fmt_spec)
[start, stop, tok] = regexp(fmt_spec, '%([\d\.]*)([a-z])', ...
'start', 'end', 'tokens');
assert(~isempty(tok) && ~isempty(tok{1}{2}), ...
['Format symbol is not found in ' fmt_spec]);
% The first cell index corresponds to different matches if
% there are more than one specifier
smb = cellfun(@(x)x{2}, tok);
% Return a substring that includes all the specifiers
format = fmt_spec(min(start):max(stop));
end
% List validation function with case-insensitive comparison
function f = createScpiListValidationFcn(~, value_list)
function listValidationFcn(val)
val = lower(val);
assert( ...
any(cellfun(@(y) isequal(val, y), value_list)), ...
['Value must be one from the following list:', ...
newline, var2str(value_list)]);
end
f = @listValidationFcn;
end
% smb is an array of format specifier symbols
function f = createArrayValidationFcn(~, smb)
function validateNumeric(val)
assert((length(val) == length(smb)) && isnumeric(val), ...
sprintf(['Value must be a numeric array of length ' ...
'%i.'], length(smb)))
end
function validateInteger(val)
assert((length(val) == length(smb)) && ...
all(floor(val) == val), sprintf(['Value must be ' ...
'an integer array of length %i.'], length(smb)))
end
function validateLogical(val)
assert((length(val) == length(smb)) && ...
all(val==1 | val==0), ['Value must be a logical ' ...
'array of length ' length(smb) '.'])
end
function valudateCharacterString(val)
assert(ischar(val), 'Value must be a character string.');
end
% Determine the type of validation function
if all(smb == 's' | smb == 'c')
f = @valudateCharacterString;
elseif all(smb == 'b')
f = @validateLogical;
elseif all(smb == 'b' | smb == 'i')
f = @validateInteger;
else
f = @validateNumeric;
end
end
function val = createValidValue(~, smb)
if all(smb == 's' | smb == 'c')
val = '';
elseif all(smb == 'b')
val = false(length(smb), 1);
else
val = zeros(length(smb), 1);
end
end
end
end
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