Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Mon, 17 Jan 2011 15:35:33 -0600

This is the code in asyn drvAsynIPPort.c readIt() function:

    thisRead = recv(tty->fd, data, maxchars, 0);
    if (thisRead > 0) {
        asynPrintIO(pasynUser, ASYN_TRACEIO_DRIVER, data, thisRead,
                   "%s read %d\n", tty->IPDeviceName, thisRead);
        tty->nRead += thisRead;
    }

So the socket recv() function is only returning a single character.
That's not how most devices work, most send multiple characters in a
single message.  But you are presumably using the asynInterposeEos
layer, which repeatedly calls drvAsynIPPort::readIt() until it detects a
terminator, EOM, timeout, or the requested maximum number of characters.

Mark

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of John Dobbins
Sent: Monday, January 17, 2011 3:23 PM
To: EPICS Tech-Talk
Subject: StreamDevice/ASYN connection to a Telnet port

Dear All,

I am connecting to a Gamma Vacuum SPCe ion pump power supply. This
device has an ethernet port which accepts telnet connections.

I set up StremDevice to communicate with it on port 23,

I have  asyn Trace Masks set as follows:

asynSetTraceMask("SPCe",-1,0x09)
asynSetTraceIOMask("SPCe",-1,0x2

I have a problem in that the response string , which I expect to look
like  "OK 00 7.90E-13 TORR" 

appears like this:

epics> 2011/01/17 16:14:55.995 172.18.32.21:23 write 7
spc 0B\r
2011/01/17 16:14:56.475 172.18.32.21:23 read 1
O
2011/01/17 16:14:56.475 172.18.32.21:23 read 1
K
2011/01/17 16:14:56.475 172.18.32.21:23 read 1

2011/01/17 16:14:56.475 172.18.32.21:23 read 1
0
2011/01/17 16:14:56.475 172.18.32.21:23 read 1
0
2011/01/17 16:14:56.476 172.18.32.21:23 read 1

2011/01/17 16:14:56.476 172.18.32.21:23 read 1
7
2011/01/17 16:14:56.476 172.18.32.21:23 read 1
.
2011/01/17 16:14:56.476 172.18.32.21:23 read 1
9
2011/01/17 16:14:56.477 172.18.32.21:23 read 1
0
2011/01/17 16:14:56.477 172.18.32.21:23 read 1
E
2011/01/17 16:14:56.477 172.18.32.21:23 read 1
-
2011/01/17 16:14:56.477 172.18.32.21:23 read 1
1
2011/01/17 16:14:56.478 172.18.32.21:23 read 1
3
2011/01/17 16:14:56.478 172.18.32.21:23 read 1

2011/01/17 16:14:56.478 172.18.32.21:23 read 1
T
2011/01/17 16:14:56.478 172.18.32.21:23 read 1
O
2011/01/17 16:14:56.478 172.18.32.21:23 read 1
R
2011/01/17 16:14:56.479 172.18.32.21:23 read 1
R
2011/01/17 16:14:56.479 172.18.32.21:23 read 1
\r

Can someone tell me what is going on here?

Regards and thanks,

John Dobbins

Cornell University
Lab for Elementary Particle Physics

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System