This demo explores saving your instrument control session. Two methods for saving your session are available. The first method uses the SAVE command to save the instrument objects to a MAT-file. The LOAD command is used to load the instrument objects from the MAT-file back into the MATLAB workspace. The second method uses the OBJ2MFILE function to convert the instrument object to the equivalent MATLAB code. The instrument object can be recreated later by running the M-file.
The information obtained for this demonstration was prerecorded. Therefore, you do not need an actual instrument to learn about saving your instrument control session. The instrument used was a Tektronix TDS 210 oscilloscope.
To begin, create a serial port object associated with the COM1 port.
>> s=serial('COM1')Serial Port Object : Serial-COM1
Communication Settings
Port: COM1
BaudRate: 9600
Terminator: 'LF' Communication State
Status: closed
RecordStatus: off Read/Write State
TransferStatus: idle
BytesAvailable: 0
ValuesReceived: 0
ValuesSent: 0The Tag, UserData, BaudRate, and InputBufferSize properties will be configured as follows:
>> s.Tag = 'sydney'; >> s.UserData = magic(5); >> s.BaudRate = 4800; >> s.InputBufferSize = 2500;
Before you can perform a read or write operation, you must connect the serial port object to the instrument with the FOPEN function. If the object was successfully connected, its Status property is configured to open.
>> fopen(s) >> s.Status
ans =
open
Now query the instrument's identification information. By default, the serial port object stores the information in its input buffer.
>> fprintf(s,'*IDN?') >> get(s, 'BytesAvailable')
ans =
56
>> get(s, ValuesSent')
ans =
6
The serial port object can be saved to a MAT-file with the MATLAB built-in SAVE command. Any data in the object's input buffer will not be stored with the object in the MAT-file. Therefore, if you do not want to lose this data, you must read the data into the workspace with one of the read functions such as FSCANF. You must explicitly save the variable containing the data to the MAT-file.
>> data = fscanf(s)
data =
TEKTRONIX,TDS 210,0,CF:91.1CT FV:v1.16 TDS2CM:CMV:v1.04
>> save fname s data >> clear data >> fclose(s) >> delete(s); >> clear s
You can recreate the instrument object and its data (if saved) with the MATLAB built-in LOAD command.
It is important to note that values for read-only properties will be restored to their default values upon loading. For example, any instrument objects that are saved while connected will be loaded with their Status property set to closed.
>> load fname >> s
Serial Port Object : Serial-COM1
Communication Settings
Port: COM1
BaudRate: 4800
Terminator: 'LF' Communication State
Status: closed
RecordStatus: off Read/Write State
TransferStatus: idle
BytesAvailable: 0
ValuesReceived: 0
ValuesSent: 0>> data
data =
TEKTRONIX,TDS 210,0,CF:91.1CT FV:v1.16 TDS2CM:CMV:v1.04
>> get(s, {'Tag', 'InputBufferSize'})ans =
'sydney' [2500]
>> get(s, 'UserData')
ans =
17 24 1 8 15
23 5 7 14 16
4 6 13 20 22
10 12 19 21 3
11 18 25 2 9OBJ2MFILE converts an instrument object to its equivalent MATLAB code. The instrument object can be recreated by running the created M-file.
Create a GPIB object that will be converted to M-Code.
>> g = gpib('ni', 0, 1);
>> g.Tag = 'mygpib';
>> g.EOIMode = 'off';
>> g.UserData = magic(5);By default, OBJ2MFILE saves properties not set to their default values using the SET syntax. A MAT-file with the same name as the M-file will also be created if
>> obj2mfile(g, 'fname');
The M-file created by OBJ2MFILE is shown below. Note the first line following the online help indicates the time the M-file was created.
>> type fname.m
function out = fname %FNAME M-Code for creating an instrument object. % % This is the machine generated representation of an instrument object. % This M-file, FNAME.M, was generated from the OBJ2MFILE function. % A MAT-file is created if the object's UserData property is not % empty or if any of the callback properties are set to a cell array % or to a function handle. The MAT-file will have the same name as the % M-file but with a .MAT extension. To recreate this instrument object, % type the name of the M-file, myfile, at the MATLAB command prompt. % % The M-file, FNAME.M and its associated MAT-file, FNAME.MAT (if % it exists) must be on your MATLAB PATH. For additional information % on setting your MATLAB PATH, type 'help addpath' at the MATLAB % command prompt. % % Example: % g = fname; % % See also SERIAL, GPIB, VISA, TCPIP, INSTRHELP, INSTRUMENT/PROPINFO. %
% Creation time: 28-Apr-2000 14:06:21
% Load the MAT-file which contains UserData and callback property values. load fname
% Create the instrument object.
obj1 = gpib('NI', 0, 1);% Set the property values. set(obj1, 'EOIMode', 'off'); set(obj1, 'Tag', 'mygpib'); set(obj1, 'UserData', userdata1);
if nargout > 0
out = [obj1];
endYou can recreate the object by typing the name of the M-file at the MATLAB command prompt.
>> delete(g); >> clear g >> g = fname
GPIB Object Using NI Adaptor : GPIB0-1
Communication Address
BoardIndex: 0
PrimaryAddress: 1
SecondaryAddress: 0 Communication State
Status: closed
RecordStatus: off Read/Write State
TransferStatus: idle
BytesAvailable: 0
ValuesReceived: 0
ValuesSent: 0>> get(g, {'EOIMode', 'Tag'})ans =
'off' 'mygpib'
>> g.UserData
ans =
17 24 1 8 15 23 5 7 14 16 4 6 13 20 22 10 12 19 21 3 11 18 25 2 9
OBJ2MFILE also allows you to save properties using the dot notation. Additionally, you can choose to save all properties, regardless if they have been modified.
>> obj2mfile(g, 'fname', 'dot', 'all'); >> type fname.m
function out = fname %FNAME M-Code for creating an instrument object. % % This is the machine generated representation of an instrument object. % This M-file, FNAME.M, was generated from the OBJ2MFILE function. % A MAT-file is created if the object's UserData property is not % empty or if any of the callback properties are set to a cell array % or to a function handle. The MAT-file will have the same name as the % M-file but with a .MAT extension. To recreate this instrument object, % type the name of the M-file, myfile, at the MATLAB command prompt. % % The M-file, FNAME.M and its associated MAT-file, FNAME.MAT (if % it exists) must be on your MATLAB PATH. For additional information % on setting your MATLAB PATH, type 'help addpath' at the MATLAB % command prompt. % % Example: % g = fname; % % See also SERIAL, GPIB, VISA, TCPIP, INSTRHELP, INSTRUMENT/PROPINFO. %
% Creation time: 28-Apr-2000 14:14:00
% Load the MAT-file which contains UserData and callback property values. load fname
% Create the instrument object.
obj1 = gpib('NI', 0, 1);% Set the property values. obj1.BoardIndex = 0; obj1.ByteOrder = 'littleEndian'; obj1.BytesAvailableFcn = ''; obj1.BytesAvailableFcnCount = 48; obj1.BytesAvailableFcnMode = 'eosCharCode'; obj1.CompareBits = 8; obj1.EOIMode = 'off'; obj1.EOSCharCode = 10; obj1.EOSMode = 'none'; obj1.ErrorFcn = ''; obj1.InputBufferSize = 512; obj1.Name = 'GPIB0-1'; obj1.OutputBufferSize = 512; obj1.OutputEmptyFcn = ';' obj1.PrimaryAddress = 1; obj1.RecordDetail = 'compact'; obj1.RecordMode = 'overwrite'; obj1.RecordName = 'record.txt'; obj1.SecondaryAddress = 0; obj1.Tag = 'mygpib'; obj1.Timeout = 10; obj1.TimerFcn = ''; obj1.TimerPeriod = 1; obj1.UserData = userdata1;
if nargout > 0
out = [obj1];
end