Saving and Loading Instrument Objects
Saving Instrument Objects to a File
You can save an instrument object to a file using the obj2mfile
function. obj2mfile
provides
you with these options:
Save all property values or save only those property values that differ from their default values.
Read-only property values are not saved. Therefore, read-only properties use their default values when you load the instrument object into the MATLAB® workspace. To determine if a property is read-only, use the
propinfo
function or examine the property reference pages.Save property values using the
set
syntax or the dot notation.
If the UserData
property is not empty,
or if a callback property is set to a cell array of values or a function
handle, then the data stored in these properties is written to a MAT-file
when the instrument object is saved. The MAT-file has the same name
as the file containing the instrument object code.
For example, suppose you create the GPIB object g
,
return instrument identification information to the variable out
,
and store out
in the UserData
property.
g = gpib('ni',0,1); g.Tag = 'My GPIB object'; fopen(g) cmd = '*IDN?'; fprintf(g,cmd) out = fscanf(g); g.UserData = out;
The following command saves g
and the modified
property values to the file mygpib.m
. Because the UserData
property
is not empty, its value is automatically written to the MAT-file mygpib.mat
.
obj2mfile(g,'mygpib.m');
Use the type
command
to display mygpib.m
at the command line.
Loading the Instrument Object
To load an instrument object that was saved as a file into the MATLAB workspace,
type the name of the file at the command line. For example, to load g
from
the file mygpib.m
,
g = mygpib
The display summary for g
is shown below.
Note that the read-only properties such as Status
, BytesAvailable
, ValuesReceived
,
and ValuesSent
are restored to their default
values.
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
When loading g
into the workspace, the MAT-file mygpib.mat
is
automatically loaded and the UserData
property
value is restored.
g.UserData ans = TEKTRONIX,TDS 210,0,CF:91.1CT FV:v1.16 TDS2CM:CMV:v1.04
Saving Objects to a MAT-File
You can save an instrument object to a MAT-file just as you
would any workspace variable — using the save
command. For example, to save
the GPIB object g
and the variables cmd
and out
,
defined in Saving Instrument Objects to a File, to the MAT-file mygpib1.mat
,
save mygpib1 g cmd out
Read-only property values are not saved. Therefore, read-only
properties use their default values when you load the instrument object
into the MATLAB workspace. To determine if a property is read-only,
use the propinfo
function
or examine the property reference pages.
Loading the Instrument Object
To load an instrument object that was saved to a MAT-file into
the MATLAB workspace, use the load
command.
For example, to load g
, cmd
,
and out
from MAT-file mygpib1.mat
,
load mygpib1
The display summary for g
is shown below.
Note that the read-only properties such as Status
, BytesAvailable
, ValuesReceived
,
and ValuesSent
are restored to their default
values.
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