Problem writing serial data to ASI stage

Francesco Kut

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Oct 25, 2010, 4:06:05 AM10/25/10

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Hello,
I am having problems writing serial data to an ASI stage.
Code is simple:

stagePort = serial('com1') %the only port
set(stagePort, 'baudrate', 9600, 'parity', 'none','databits', 8,'stopbits', 1,'outputbuffersize', 512,'inputbuffersize', 1024,'flowControl', 'none')
fopen(stagePort)
fwrite(stagePort, [char(255) char(66)]); %entering low level commands mode
pause(.5)
fwrite(stagePort, [char(24) char(45) char(0) char(58)]); %decrease X
pause(.5)
fwrite(stagePort, [char(24) char(43) char(0) char(58)]); %increase X
pause(.5)
fwrite(stagePort, [char(25) char(45) char(0) char(58)]); %decrease Y
pause(.5)
fwrite(stagePort, [char(25) char(43) char(0) char(58)]); %increase Y
fclose(stagePort)
delete(stagePort)

The stage moves with the first input, moves with the second input too but always in the same direction, does not move at all when I increase/decrease Y.
What am I doing wrong?
The commands are correct (from manual) but it seems like the signal out is always the same, no matter what I send.
For information I am on Vista 64bit using Matlab 2009b 32 bit.
Thank you

Trent Jarvi

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Oct 25, 2010, 9:41:10 AM10/25/10

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"Francesco Kut" <heo...@gmail.com> wrote in message
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Hi Francesco

I just tested your code with an RS232 loopback connection to see what went
on the wire in your example. Everything looks fine:

ans =

255 66

ans =

24 45 0 58

ans =

24 43 0 58

ans =

25 45 0 58

ans =

25 43 0 58

Those are 8 bit bytes. Perhaps the stage needs more time to complete its
movement?

Francesco Kut

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Oct 25, 2010, 10:53:04 AM10/25/10

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Thank you Travis,
it is not the pause time the problem. I tried sending 5 steps and all the steps are completed on time.
My guess is I have a terminator problem, the instruction says:

"Group 5: Last Byte This is a one-byte end-of-command character ':'. The MS-2000 will not recognize a command until this character is received. When the ':' is received, the MS-2000 goes to a subroutine which then pulls Groups 1-4 out of the serial port buffer, and then searches the buffer until the ':' is found. Any information between Group 4 and the ':' is ignored."

How is the terminator handled and how can I set it to be ':' in matlab?
Thank you,

Francesco

Trent Jarvi

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Oct 25, 2010, 2:29:43 PM10/25/10

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"Francesco Kut" <heo...@gmail.com> wrote in message

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Hi Francesco,

Since you have 0's in your messages, I don't recommend using the terminator
character property of the serial object. Instead, just send the terminator
with fwrite.

fwrite(stagePort,[char(25) char(43) char(0) char(58) ';'])

I didn't understand the group 1-4 information mentioned. You will need to
decide where to send the terminator character. The example above just sends
it after a command.

Francesco Kut

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Oct 25, 2010, 7:05:06 PM10/25/10

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Thank you for your advice,
I tried and checked also if the command through serial port was correct and it was.
But it does not work.
Thus I switched to high level with all the consequent problems.
Long story short:
for some reason the <CR> command at the end of line written with fprintf(serial,'CMD') does not go on the serial.
But: if you write fwrite(serial,['CMD',13]) where 13 is the ascii for <CR> (the terminator needed for high level commands).
and finally it works.
Without 13 the command does not send <CR>, using \r does not work.
Thank you for your help, hope somebody will find this useful.