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rINSTCONTROL/@MyScpiInstrument/MyScpiInstrument.m
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MyScpiInstrument.m
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% Class for instruments supporting SCPI, features specialized framework for
% read/write commands
classdef MyScpiInstrument < MyInstrument
properties (SetAccess=protected, GetAccess=public)
%Contains a list of the commands available for the instrument as
%well as the default values and input requirements
CommandList
%Parses commands using an inputParser object
CommandParser
en_set_cb=true; %enable set callback
end
properties (Dependent=true)
command_names
command_no
write_commands
read_commands
end
methods (Access=public)
%% Class constructor
function this=MyScpiInstrument(interface, address, varargin)
this@MyInstrument(interface, address, varargin{:});
this.CommandList=struct();
createCommandList(this);
createCommandParser(this);
end
%% Low-level functions for reading and writing textual data to the device
% These functions can be overloaded if the instrument does not
% support visa communication or use non-standard command separators
function writeCommand(this, varargin)
if ~isempty(varargin)
% Concatenate commands and send to the device
cmd_str=join(varargin,';');
cmd_str=cmd_str{1};
fprintf(this.Device, cmd_str);
end
end
% Query commands and return resut as cell array of strings
function res_list=queryCommand(this, varargin)
if ~isempty(varargin)
% Concatenate commands and send to the device
cmd_str=join(varargin,';');
cmd_str=cmd_str{1};
res_str=query(this.Device, cmd_str);
% Drop the end-of-the-string symbol and split
res_list=split(deblank(res_str),';');
else
res_list={};
end
end
%% Read and write commands
%Writes properties to device. Can take multiple inputs. With the
%option all, the function writes default to all the
%available writeable parameters.
function writeProperty(this, varargin)
set_cb_was_enabled = this.en_set_cb;
%Switch PostSet callbacks off to prevent infinite recursion
this.en_set_cb=false;
%Parses the inputs using the CommandParser
parse(this.CommandParser, varargin{:});
if this.CommandParser.Results.all
% If the 'all' is true, write all the commands
exec=this.write_commands;
else
% Check which commands were passed values
ind_val=cellfun(@(x)...
(~ismember(x, this.CommandParser.UsingDefaults)),...
this.write_commands);
exec=this.write_commands(ind_val);
end
% Create a list of textual strings to be sent to device
exec_commands=cell(1,length(exec));
for i=1:length(exec)
%Create command using the right string spec
cmd=[this.CommandList.(exec{i}).command,...
' ',this.CommandList.(exec{i}).fmt_spec];
val=this.CommandParser.Results.(exec{i});
exec_commands{i}=sprintf(cmd, val);
end
% Sends commands to device
writeCommand(this, exec_commands{:});
for i=1:length(exec)
%Assign written values to instrument properties
this.(exec{i})=this.CommandParser.Results.(exec{i});
end
% Leave en_set_cb in the same state it was found
this.en_set_cb=set_cb_was_enabled;
end
% Wrapper for writeProperty that opens and closes the device
function writePropertyHedged(this, varargin)
was_open = isopen(this);
openDevice(this);
try
writeProperty(this, varargin{:});
catch
warning('Error while writing the properties:');
disp(varargin);
end
readProperty(this, 'all');
% Leave device in the state it was in the beginning
if ~was_open
closeDevice(this);
end
end
function result=readProperty(this, varargin)
set_cb_was_enabled = this.en_set_cb;
%Switch PostSet callbacks off to prevent infinite recursion
this.en_set_cb=false;
result = struct();
read_all_flag = any(strcmp('all',varargin));
if read_all_flag
% Read all the commands with read access
exec=this.read_commands;
else
ind_r=ismember(varargin,this.read_commands);
exec=varargin(ind_r);
if any(~ind_r)
% Issue warnings for commands not in the command_names
warning('The following are not valid read commands:');
disp(varargin(~ind_r));
end
end
% Create a list of textual strings to be sent to device
exec_commands=cellfun(...
@(cmd)[this.CommandList.(cmd).command,'?'],exec,...
'UniformOutput',false);
% Query device
res_list=queryCommand(this, exec_commands{:});
% Assign outputs to the class properties
if length(exec)==length(res_list)
for i=1:length(exec)
result.(exec{i})=sscanf(res_list{i},...
this.CommandList.(exec{i}).fmt_spec);
%Assign the values to the MyInstrument properties
this.(exec{i})=result.(exec{i});
end
else
warning(['Not all the properties could be read, ',...
'no instrument class values are not updated']);
end
% Leave en_set_cb in the same state it was found
this.en_set_cb=set_cb_was_enabled;
% Trigger notification abour new properties read
triggerPropertyRead(this);
end
% Wrapper for readProperty that opens and closes the device
function result=readPropertyHedged(this, varargin)
was_open = isopen(this);
openDevice(this);
try
result = readProperty(this, varargin{:});
catch
warning('Error while reading the properties:');
disp(varargin);
end
% Leave device in the state it was in the beginning
if ~was_open
closeDevice(this);
end
end
% readHeader function
function Hdr=readHeader(this)
%Call parent class method and then append parameters
Hdr=readHeader@MyInstrument(this);
%Hdr should contain single field
readPropertyHedged(this,'all');
for i=1:length(this.read_commands)
cmd = this.read_commands{i};
addParam(Hdr, Hdr.field_names{1}, cmd, this.(cmd), ...
'comment', this.CommandList.(cmd).info);
end
end
%% Processing of the class variable values
% Extend the property value based on val_list
function std_val = standardizeValue(this, cmd, varargin)
if ~ismember(cmd,this.command_names)
warning('%s is not a valid command',cmd);
std_val = '';
return
end
vlist = this.CommandList.(cmd).val_list;
% The value to normalize can be explicitly passed as
% varargin{1}, otherwise use this.cmd as value
if isempty(varargin)
val = this.(cmd);
else
val = varargin{1};
end
% find matching commands
ismatch = false(1,length(vlist));
for i=1:length(vlist)
n = min([length(val), length(vlist{i})]);
% compare first n symbols disregarding case
ismatch(i) = strncmpi(val, vlist{i},n);
end
% out of matching names pick the longest
if any(ismatch)
mvlist = vlist(ismatch);
%Finds the length of each element of mvlist
n_el=cellfun(@(x) length(x), mvlist);
%Sets std_val to the longest element
std_val=mvlist{n_el==max(n_el)};
% sets the property if value was not given explicitly
if isempty(varargin)
this.(cmd) = std_val;
end
else
warning(['The value %s is not in the val_list ',...
'of %s command'], val, cmd)
std_val = val;
end
end
% Return the list of long command values excluding abbreviations
function std_val_list = stdValueList(this, cmd)
if ~ismember(cmd,this.command_names)
warning('%s is not a valid command',cmd);
std_val_list = {};
return
end
vlist = this.CommandList.(cmd).val_list;
% Select the commands, which appear only once in the beginnings
% of the strings in val_list
long_val_ind = cellfun(...
@(x)(sum(startsWith(vlist,x,'IgnoreCase',true))==1),vlist);
std_val_list = vlist(long_val_ind);
end
%% Auxiliary functions for auto format assignment to commands
function fmt_spec=formatSpecFromAttributes(~,classes,attributes)
if ismember('char',classes)
fmt_spec='%s';
elseif ismember('logical',classes)||...
(ismember('numeric',classes)&&...
ismember('integer',attributes))
fmt_spec='%i';
else
%assign default value, i.e. double
fmt_spec='%e';
end
end
function [class,attribute]=attributesFromFormatSpec(~, fmt_spec)
% find index of the first letter after the % sign
ind_p=strfind(fmt_spec,'%');
ind=ind_p+find(isletter(fmt_spec(ind_p:end)),1)-1;
fmt_spec_letter=fmt_spec(ind);
switch fmt_spec_letter
case {'d','f','e','g'}
class={'numeric'};
attribute={};
case 'i'
class={'numeric'};
attribute={'integer'};
case 's'
class={'char'};
attribute={};
case 'b'
class={'logical'};
attribute={};
otherwise
% Any of the above classes will pass
class={'numeric','char','logical'};
attribute={};
end
end
end
methods (Access=protected)
%% Command list handling
%Adds a command to the CommandList
function addCommand(this, tag, command, varargin)
p=inputParser();
addRequired(p,'tag',@ischar);
addRequired(p,'command',@ischar);
addParameter(p,'default','placeholder');
addParameter(p,'classes',{},@iscell);
addParameter(p,'attributes',{},@iscell);
addParameter(p,'fmt_spec','%e',@ischar);
% list of the values the variable can take, {} means no
% restriction
addParameter(p,'val_list',{},@iscell);
addParameter(p,'access','rw',@ischar);
% information about the command
addParameter(p,'info','',@ischar);
parse(p,tag,command,varargin{:});
%Adds the command to be sent to the device
this.CommandList.(tag).command=command;
this.CommandList.(tag).access=p.Results.access;
this.CommandList.(tag).write_flag=contains(p.Results.access,'w');
this.CommandList.(tag).read_flag=contains(p.Results.access,'r');
this.CommandList.(tag).default=p.Results.default;
this.CommandList.(tag).val_list=p.Results.val_list;
this.CommandList.(tag).info=p.Results.info;
% Adds the string specifier to the list. if the format
% specifier is not given explicitly, try to infer
if ismember('fmt_spec', p.UsingDefaults)
this.CommandList.(tag).fmt_spec=...
formatSpecFromAttributes(this,p.Results.classes...
,p.Results.attributes);
elseif strcmp(p.Results.fmt_spec,'%b')
% b is a non-system specifier to represent the
% logical type
this.CommandList.(tag).fmt_spec='%i';
else
this.CommandList.(tag).fmt_spec=p.Results.fmt_spec;
end
% Adds the attributes for the input to the command. If not
% given explicitly, infer from the format specifier
if ismember('classes',p.UsingDefaults)
[this.CommandList.(tag).classes,...
this.CommandList.(tag).attributes]=...
attributesFromFormatSpec(this, p.Results.fmt_spec);
else
this.CommandList.(tag).classes=p.Results.classes;
this.CommandList.(tag).attributes=p.Results.attributes;
end
% Adds a property to the class corresponding to the tag
if ~isprop(this,tag)
h=addprop(this,tag);
% Enable PreSet and PostSet events
h.SetObservable=true;
% No AbortSet is the lesser of evils
h.AbortSet=false;
% Store property handle
this.CommandList.(tag).prop_handle=h;
end
this.(tag)=p.Results.default;
% Add callback to PostSet event that writes the value, assigned
% to the instrument class property, to the prysical devices and
% reads it back. There is no point in storing listeners to
% clean them up as here the generating and receiving objects
% are the same and listeners are destroyed with the generating
% object.
addlistener(this,tag,'PostSet',@(src,~)propPostSetCb(this,src));
end
%Creates inputParser using the command list
function p = createCommandParser(this)
%Use input parser
%Requires input of the appropriate class
p=inputParser;
p.StructExpand=0;
%Flag for whether the command should initialize the device with
%defaults
addParameter(p, 'all',false,@islogical);
for i=1:length(this.write_commands)
%Adds optional inputs for each command, with the
%appropriate default value from the command list and the
%required attributes for the command input.
tag=this.write_commands{i};
% Create validation function based on properties:
% class, attributes and list of values
if ~isempty(this.CommandList.(tag).val_list)
if all(cellfun(@ischar, this.CommandList.(tag).val_list))
% for textual values use case insentice string comparison
v_func = @(x) any(cellfun(@(y) strcmpi(y, x),...
this.CommandList.(tag).val_list));
else
% for everything else compare as it is
v_func = @(x) any(cellfun(@(y) isequal(y, x),...
this.CommandList.(tag).val_list));
end
else
v_func = @(x) validateattributes(x,...
this.CommandList.(tag).classes,...
this.CommandList.(tag).attributes);
end
addParameter(p, tag,...
this.CommandList.(tag).default, v_func);
end
this.CommandParser=p;
end
%Dummy empty function that needs to be redefined in a subclass to
%incorporate addCommand statements
function createCommandList(~)
end
%% Property PostSet callback
function propPostSetCb(this,src)
if this.en_set_cb
writePropertyHedged(this,src.Name,this.(src.Name));
end
end
end
%% Get functions
methods
function command_names=get.command_names(this)
command_names=fieldnames(this.CommandList);
end
function write_commands=get.write_commands(this)
ind_w=structfun(@(x) x.write_flag, this.CommandList);
write_commands=this.command_names(ind_w);
end
function read_commands=get.read_commands(this)
ind_r=structfun(@(x) x.read_flag, this.CommandList);
read_commands=this.command_names(ind_r);
end
function command_no=get.command_no(this)
command_no=length(this.command_names);
end
end
end
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