telnet to Cognex In-Sight 4001 camera

[chris.annin at gmail.com]

On Monday, February 25, 2013 9:02:54 AM UTC-8, chris... at gmail.com wrote:
> Hello,  ive been struggling with this for a couple weeks now and was hoping someone might be able to help.  I have an older Cognex camera that I need to communicate with via telnet.  I can get a response from the camera when I initiate a telnet session but I dont seem to get any response when I write the user name to the camera -  I havnt been able to get any response writing anything. Im using python 2.7 and windows xp.  here is the code:
> 
> [code]
> 
> >>>import sys
> 
> >>>import telnetlib
> 
> >>>HOST = "10.31.18.21"
> 
> >>>USER = "admin"
> 
> >>>tn = telnetlib.Telnet(HOST)
> 
> >>>tn.read_until("Login: ")
> 
> "Welcome to In-Sight(R) 4001 Session 1\r\nUser:"
> 
> >>>tn.write(USER + "\r\n")
> 
> >>>tn.read_until("User: ")
> 
> Traceback (most recent call last):
> 
>   File "<stdin>", line 1, in <module>
> 
>   File "C:\Python27\lib\telnetlib.py", line 319,
> 
>     return self.read_very_lazy()
> 
>   File "C:\Python27\lib\telnetlib.py", line 395,
> 
>     raise EOFError, 'telnet connection closed'
> 
> EOFError: telnet connection closed
> 
> >>>
> 
> [\code]
> 
> 
> 
> if i do a read_all instead of read_until for user I just get "..." returned.  Im assuming tn.write command isnt working?  any help would be greatly appreciated.
> 
> 
> 
> thank you
> 
> 
> 
> Chris

After much goofing around I figured out that every time I read from this Cognex 4000 series camera the connection either goes dead or disconnects.  If I simply stop trying to read_until or read_all and just write everything it works fine.  here is what worked for me:

import sys
import telnetlib
host = "10.31.18.21"
tn = telnetlib.Telnet(host)
tn.write("admin\r\n") #the user name is admin
tn.write("\r\n") #there is no password - just return - now logged in
tn.write("SO0\r\n") #"SO"=cognex "set online" therefore "SO0" = camera offline
tn.write("LFsomevisionjob.job\r\n") #"LF" = cognex native command "load file"
tn.write("SO1\r\n") #"SO"=cognex "set online" therefore "SO1" = camera online
tn.close()

I doubt anyone has a camera this old they are trying to telnet to in python but if so maybe this thread will help someone out.

thanks again for all your replies - really appreciate you guys helping me out.
Chris