Controling a Tektronix Oscilloscope Model: DPO5204B-5RL

I am having problems with using num2str with controlling the scope. I am not getting the correct setting. When I put the number directly in without num2str everything works. Is there a bug.

Code sample of what I am having errors with.

%fprintf(myScope,strcat('HORIZONTAL:MODE:SCAle ',num2str(5e-4)));          % Sets the Time/Division
a=num2str(.5e-3)
fprintf(myScope,strcat('HORizontal:MODE:SCAle ',num2str(a)));          % Sets the Time/Division
fprintf(myScope,strcat('HORIZONTAL:MODE:SAMPLERATE 1e9'));
fprintf(myScope,strcat('HORizontal:MODE:RECOrdlength 5*1e6'));
%fprintf(myScope,strcat('HORizontal:MODE:SCAle ',num2str(Time_Division*1e-3)));          % Sets the Time/Division
%fprintf(myScope,strcat('HORIZONTAL:MODE:SAMPLERATE ',num2str(Sample_Rate*1e6)));        % Sets the Sample_Rate
%fprintf(myScope,strcat('HORIZONTAL:MODE:SAMPLERATE 5e6'));  
%fprintf(myScope,strcat('HORIZONTAL:MODE:SAMPLERATE?'))
%fprintf(myScope,strcat('HORizontal:MODE:RECOrdlength ',num2str(Record_Length*1e6)));    % Sets the Record_Length

Below is the full program

% Program Name: Instrument Program
% Program Date: 8/11/2016
% Program Version: 1.0
% Written By: William K. Grefe M.S.

% Required Software & Software Version that the program has been verified with
% MATLAB                        Version 9.0        (R2016a)
% Instrument Control Toolbox    Version 3.9        (R2016a)
% Signal Processing Toolbox     Version x.xx       (R2016a)

% Works with the Following Hardware
% Tektronix Oscilloscope Model: DPO5204B-5RL driver has been written to be used in this code

% Instrument Program Description: 
% Automatically connects to the Oscilloscope,sets up the parameters, saves
% data to a file on the computer that it is connected to.
% 
% clrdevice       % clrdevice
% fopen           % Connect interface object to instrument
% set             % Configure or display instrument object properties

%doc oscilloscope

% Set Time Division (msec/div)
% Read Time Division (msec/div) and write into excel
% Set Sample Rate (MHz)
% Read Sample Rate (MHz) and write into excel
% Read and write Record Length (M) into excel

% Program Name: Configuration
% Program Date: 8/30/2016
% Program Version: 1.0
% Written By: William K. Grefe M.S.

% Required Software & Software Version that the program has been verified with
% MATLAB                        Version 9.0        (R2016a)
% Instrument Control Toolbox    Version 3.9        (R2016a)
% Signal Processing Toolbox     Version 7.2        (R2016a)

% Works with the Following Hardware
% Tektronix Oscilloscope Model: DPO5204B-5RL driver has been written to be used in this code

% Configuration: 
% Reads the configuration Excel File sets up the instrument and then after
% the test auto populates the analysis file

filename='Scope_Configuration.xlsx';
sheet=1;                                                % Sheet # that data is being read from 
Row_to_Read=2;

xlRange=strcat('B',num2str(Row_to_Read));                % Cell # that data is being read from                                         
[~,~,raw]=xlsread(filename,sheet,xlRange);              % Reads the configuration data from an excel file
Laser_Model=raw;

xlRange=strcat('C',num2str(Row_to_Read));                % Cell # that data is being read from  
[~,~,raw]=xlsread(filename,sheet,xlRange);              % Reads the configuration data from an excel file
Laser_Power=raw;                                       % Reads the configuration data from an excel file

xlRange=strcat('D',num2str(Row_to_Read));                % Cell # that data is being read from  
[~,~,raw]=xlsread(filename,sheet,xlRange);              % Reads the configuration data from an excel file
Oscilloscope_Model=raw;

xlRange=strcat('E',num2str(Row_to_Read));                % Cell # that data is being read from  
Time_Division=xlsread(filename,sheet,xlRange);          % Reads the configuration data from an excel file
Time_Division
xlRange=strcat('F',num2str(Row_to_Read));                % Cell # that data is being read from  
Sample_Rate=xlsread(filename,sheet,xlRange);            % Reads the configuration data from an excel file
Sample_Rate
xlRange=strcat('G',num2str(Row_to_Read));                % Cell # that data is being read from  
Record_Length=xlsread(filename,sheet,xlRange);          % Reads the configuration data from an excel file
Record_Length

xlRange=strcat('K',num2str(Row_to_Read));                % Cell # that data is being read from  
Slot_Width=xlsread(filename,sheet,xlRange);             % Reads the configuration data from an excel file

xlRange=strcat('L',num2str(Row_to_Read));                % Cell # that data is being read from  
L_Bits_Per_Pulse=xlsread(filename,sheet,xlRange);       % Reads the configuration data from an excel file

xlRange=strcat('M',num2str(Row_to_Read));                % Cell # that data is being read from  
[~,~,raw]=xlsread(filename,sheet,xlRange);              % Reads the configuration data from an excel file
Sequence=raw;

xlRange=strcat('N',num2str(Row_to_Read));                % Cell # that data is being read from  
SET_PRF=xlsread(filename,sheet,xlRange);                % Reads the configuration data from an excel file

instrreset
visaAddress = 'TCPIP::169.254.28.185::INSTR';  % Setting the ip address.
myScope = visa('tek', visaAddress);
myScope.InputBufferSize = 1024;

% Set the |ByteOrder| to match the requirement of the instrument
myFgen.ByteOrder = 'littleEndian';

% Open the connection to the oscilloscope
fopen(myScope);

% Reset the oscilloscope to a known state
fprintf(myScope, '*RST');
fprintf(myScope, '*CLS');

% Turn headers off, this makes parsing easier
fprintf(myScope, 'HEADER OFF');

% Autoset the oscilloscope 
%fprintf(myScope, 'AUTOS EXECute');

% Ensure that the start and stop values for CURVE query match the full
% record length
fprintf(myScope, ['DATA:START 1;DATA:STOP ' Record_Length*1e6]);

% Automatically configuring the instrument 
fprintf(myScope,['SELECT:CH1 ON']);                 % Enabling Channel 1
fprintf(myScope,['SELECT:CH2 ON']);                 % Enabling Channel 2
fprintf(myScope,['SELECT:CH3 OFF']);                % Disabling Channel 3
fprintf(myScope,['SELECT:CH4 OFF']);                % Disabling Channel 4

% What are the vertical channel settings the voltage range for the channel
% 1 and channel 2 volts per division

% What the trigger level is set to 1 to 2 volts on rising edge channel 1

%fprintf(myScope,strcat('HORIZONTAL:MODE:SCAle ',num2str(5e-4)));          % Sets the Time/Division
a=num2str(.5e-3)
fprintf(myScope,strcat('HORizontal:MODE:SCAle ',num2str(a)));          % Sets the Time/Division
fprintf(myScope,strcat('HORIZONTAL:MODE:SAMPLERATE 1e9'));
fprintf(myScope,strcat('HORizontal:MODE:RECOrdlength 5*1e6'));
%fprintf(myScope,strcat('HORizontal:MODE:SCAle ',num2str(Time_Division*1e-3)));          % Sets the Time/Division
%fprintf(myScope,strcat('HORIZONTAL:MODE:SAMPLERATE ',num2str(Sample_Rate*1e6)));        % Sets the Sample_Rate
%fprintf(myScope,strcat('HORIZONTAL:MODE:SAMPLERATE 5e6'));  
%fprintf(myScope,strcat('HORIZONTAL:MODE:SAMPLERATE?'))
%fprintf(myScope,strcat('HORizontal:MODE:RECOrdlength ',num2str(Record_Length*1e6)));    % Sets the Record_Length

% Clean up Close the connection
fclose(myScope);
% Clear the variable
clear myScope;

Answer 1

[Vinod Cherian]

The fact that it works when you have actual numbers tells me this is not so much an instrument issue as it is a code issue. It is really difficult to parse your post because of the formatting, so I can't be sure this is what it is.

My recommendation to debug the issue you are seeing is to execute each line of code, one line at a time, and see which line causes an error.

PS: To make the post readable, consider using the {}code button to denote what parts of your posting is code.

Answer 2

[Walter Roberson]

I really recommend that you use fprintf format specifiers to do the conversion so you will know exactly how they will be converted. For example,

 a = .5e-3;
 fprintf(myScope,'HORizontal:MODE:SCAle %0.4f\n', a);          % Sets the Time/Division

Have an closer look at your current code:

 a=num2str(.5e-3)
 fprintf(myScope,strcat('HORizontal:MODE:SCAle ',num2str(a)));          % Sets the Time/Division

On the first of those two lines you make a a string with the representation of 0.5e-3, and in the second of those two lines you tell it to use num2str() on what is already a string. Testing, it appears that the second num2str() will leave the string unchanged, but can you be sure?

What number formats does the device accept? How many decimal places? Easiest to code the % format to fit the exact requirement.