convert number to character
randomz_raf
Wed, 04/20/2011 - 05:21 am
I'm make a simple program using Igor to converting number to character then display the value on command window..
This is my Procedure/Function :
#pragma rtGlobals=1 // Use modern global access method.
Function Test(ctrlName) : ButtonControl
String ctrlName
Variable a,b,c,d
String test,charA,charB,charC,charD
a=0x86
b=0x00
c=0x83
d=0x00
charA=num2char (a)
charB=num2char (b)
charC=num2char (c)
charD=num2char (d)
test= charA+charB+charC+charD
Print "test:",test
End
Function Test(ctrlName) : ButtonControl
String ctrlName
Variable a,b,c,d
String test,charA,charB,charC,charD
a=0x86
b=0x00
c=0x83
d=0x00
charA=num2char (a)
charB=num2char (b)
charC=num2char (c)
charD=num2char (d)
test= charA+charB+charC+charD
Print "test:",test
End
but i have some problem with my program. When I execute my function, I did not get a character for my 'charC'. This is the result that i got on the windows command : test: †
So can any of you help me slove this problem?
the problem is that you are embedding ASCII 0, num2char(0x00), into your string. And this marks in C, and also for a few Igor functions, the end of the string. Therefore everything behind that is discarded.
Try
printf "_%s_\r", num2char(0x83) + num2char(0x00) + num2char(0x83)
Here the first gives you the expected string, the second is cutoff at num2char(0x00).
Why do you want to insert ASCII 0 into a string in the first place?
April 20, 2011 at 05:41 am - Permalink
Dear thomas_braun,
Thank you for your reply. Actually I try writing my Igor program for my TDC Histogram. In my program I need to set null character for the four parameters (d,e,b,c) to initialize the TDC device. Then I will put the four parameters into one string (test) and use the string for as a buffer in my NI4882 ibwrt function.
charB=num2char (b)
charC=num2char (c)
charD=num2char (d)
test= charA+charB+charC+charD
NI4882 ibwrt={ud,test,1}
So is it possible it will send the null (0 ASCII) to the device during ibwrt or it will set as end of string?
April 25, 2011 at 09:26 am - Permalink
Yes, that should work because NI4882 ibwrt treats the string as a black box, not as a C string.
You could also use NIGPIBWriteBinary2.
You could also use NIGPIBWriteBinaryWave2:
NIGPIBWriteBinaryWave2 test
April 25, 2011 at 09:59 am - Permalink
Thank you for your help. Which one is much more better to use, NI4882 ibwrt or NIGPIBWriteBinary2?
April 25, 2011 at 10:11 am - Permalink
It does not matter. I consider the NI488 operation to be low-level and I use the higher level operations when possible. I would tend to use NIGPIBWriteBinary2 for this situation.
April 25, 2011 at 02:26 pm - Permalink