What does the status message "not present" mean in MAX?

[Krueger30]

Hello,

     I have two instruments, a Burleigh WA-1000 wavemeter and a Tektronicx TDS 2012 B Oscilloscope, connected to a GPIB - USB converter which then goes into my computer. The MAX panel "sees" both of these instruments but designates their status as "not present" and I always get the timeout error when trying to communicate with them.

   If anyone either knows what's wrong or can give me some things to troubleshoot it would be a real help.

Thanks. 

[crossrulz]

I would start by doing the Scan for Instruments again.  If they are still there, looks to see what they returned for their identification.  There should be something there, at least for the Tektronix scope.

[Krueger30]

I scanned for instruments again, and their "not present" status is unchanged. However, both devices have tabs that I can click on.

[Dennis_Knutson]

Can you attach some screenshots?

[Krueger30]

Sure thing. Sorry I had forgotten to do that.

[Dennis_Knutson]

So the wavemeter does not respond to the identification query. If you disconnect that and rescan, does the status of the scope change?

[Krueger30]

No, nothing changed after disconnecting/reconnecting. We even switched out all of the comunication cables and there was still no change.

[JÞB]

Yeah that would do it.  That wavemeter is a bit of a tricky beast.  If you send it some commands it does understand it will lock the bus and nobody will be able to talk until it is power cycled.  *IDN? is one of those not implemented commands.  Scan for instruments sends *IDN? to each available address.

Since the instrument does not comply with the IEEE 488 standard I would not hang it on the same bus as other (more polite) intsruments to prevent interactions like this-  use the serial port or hang a second GPIB bus dedicated to serving only that non compliant device knowing you cannot use the full set of IEEE 488 commands on that bus.

WORSE! that darned wavemeter actually powers up defaulted to "Broadcast mode" so its jabbering away on the selected communications port! (WWTT?)  You'll need to send "@Q\r\n" before it shuts up so you can talk to other devices on the bus.