Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Tue, 30 Sep 2008 08:23:59 -0500

On Sep 30, 2008, at 7:58 AM, Silver wrote:
hi, all:
 I want to write a driver for one of our serial devices, so I read
"How to create EPICS device support for a simple serial or GPIB
device". (http://www.aps.anl.gov/epics/modules/soft/asyn/R4-9/HowToDoSerial/tutorial.html
)
While I have several questions:
 1. in the tutorial, it said:
Command array index 0 – Device Reset

{&DSET_LO, GPIBWRITE, IB_Q_LOW, NULL, "\377\377\033", 10, 10,

NULL, 0, 0, NULL, NULL, "\033"},

I don't understand what's the meaning of "\377\377\033", does it
mean "377" is oct number?

Yes.  That's standard C syntax.
If you prefer hexadecimal the equivalent would be "\xFF\xFF\x1B".

 2. in function "convertPositionReply" and "convertStatusReply",

first time, pli->val = pdpvt->msg[0];

second time, pli->val = pdpvt->msg[1];

Does it mean the AB300's response data begin from different
position? can anyone give me some explanation?

The AB300 response always contains both position information (in the
first character) and status information (in the second character).

I have never used GPIB device before, so forgive my innocence.
Thanks a lot in advance.

If your device is IEEE-488.2 compliant the makeSupport .pl command in
the ASYN distribution will set up a number of command table entries
that you could study. The command usage is:

<path to ASYN support module>/bin/<host archicture>/makeSupport.pl -t
devGpib <yourDeviceName>
--
Eric Norum <[email protected]>
Advanced Photon Source
Argonne National Laboratory
(630) 252-4793

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System