Controlling Instruments Using the Serial Port

I am beginner of MATALB.. I am kind of confused with sending a command to power supplier. I want to control the power supplier (set the voltage) by MATLAB

s = serial('COM22');
fopen(s);

I think it is connected, I tried to send a command (command can be found here page 39). It is something like

 <nrf> A number in any format. e.g. 12, 12·00, 1·2 e1 and 120 e-1 are all accepted as the
    number 12. Any number, when received, is converted to the required precision
    consistent with the use then rounded to obtain the value of the command.
 <n> The number of the output (1 or 2) or associated status register to which the
    command relates. On the XEL30-3DP, ‘1’ is the Master (right-hand output) and ‘2’ is
    the Slave (left-hand output). 

V<n> <nrf>  : Set output <n> to <nrf> Volts
V<n>V <nrf> : Set output <n> to <nrf> Volts with verify

So I thought I can just use fprintf, but power supplier does not do anything.

fprintf(s,'*V1V 5')

Anyone can help me a guide or what to look it up? It is quite difficult since I do not have any experience with the MATLAB.