Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Mon, 11 Dec 2000 08:40:01 -0600

Andrew Johnson wrote:
> 
> Mathew Rippa wrote:
> >
> > Has anybody experienced problems with the LanGpib driver from Benjamin Franksen
> > (any version) returning the wrong ioc address? I have consulted Peter Mueller
> > (from Bessy) on this. It looks like a bug in the call to
> > "get_myaddress(&iocAddr)".
> >
> > The driver returns only 128.171.0.0 when our actual address is 128.171.90.150
> > .. As a result it incorrectly thinks our gateway is 128.171.0.59,  which is
> > actually 128.171.90.59 .  Verbose details below...
> 
> In section 2.4 of the lanGpib documentation, ie at
> http://www-csr.bessy.de/control/SoftDist/gpib/doc/lanGpib-8.html#HEADING8-0
> there is a paragraph labeled WARNING indicating that the driver does not
> use the IOC's _subnet_ mask but its _netmask_ to determine the box's IP
> address.  128.x.x.x is a Class B address, so your netmask is 255.255.0.0,
> although your local subnet mask may be 255.255.255.0 (which is irrelevent
> for this driver).  The link part of your GPIB hardware addresses need to
> have 90*256=23040 added to them.  This caught us at APS the first time
> too.
> 

Among the changes I made to this driver when converting it to R3.14 was
one which removed this addressing problem.  I've sent the changes to
Benjamin Franksen, but I don't think he's yet made a new driver
available.  The change I made requires that a link be set up in the
st.cmd file by making a call to drvHpGpibConfig.  For example, the call

drvHpGpibConfig(0, "128.233.14.201", 0, 0, "hpib")

configures link number 0 to the E2050A whose IP number is
128.233.14.201.  If your E2050s are registered with your DNS server you
can specify the E2050 IP address by name:

drvHpGpibConfig(0, "hpgpib01", 0, 0, "hpib")

The link number (the first argument to drvHpGpibConfig) is arbitrary so
you can continue to use link numbers like 3785 for backwards
compatability with existing EPICS databases which use the R3.13 `encode
the IP number in the link number' strategy.

-- 
Eric Norum                                 [email protected]
Department of Electrical Engineering       Phone: (306) 966-5394
University of Saskatchewan                 FAX:   (306) 966-5407
Saskatoon, Canada.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System