sending error with Nat9914 to HP34401A?

[hdx]

Hi!

I'm working with the NAT9914 which is controlled by HC12. Im using one instrument "HP34401A".

I have a little problem with my NAT9914. It works when I send data- and remote messages until a question "?" command is sent.
I'm recieving the data correctly. But if i want to send anything again after the guestion message, the instrument will generate two errors -101 and -113 depending on what i'm sending, "*" or ":".

For example:
conf:freq => error -113 when ":" is sent.
*cls => error -101 when "*" is sent.

The NAT does not indicate something strange in the ISR registers.

Thanks!

RH

[pavanb]

What does the instrument manual say for these errors?

[hdx]

It says:

-101:
Undefined header
A command was received that is not valid for this multimeter. You may have misspelled the command or it may not be a valid command. If you are using the short form of the command, remember that it may contain
up to four letters. Example: TRIGG:COUN 3

-113:
Invalid character
An invalid character was found in the command string. You may have inserted a character such as #, $, or % in the command header or within a parameter. Example: CONF:VOLT#DC

I would be very thankful for an answer!

RH

[hdx]

One more thing:
When the DIR register contains FF everything works, but when it contains 0A(EOSR character) it will work like I described in the first post. But this shouldn't be a problem?

[Randy Solomonson]

Hello-

Do you mean that the Unlisten (UNL) command byte is attempting to be sent? It sounds like it's going through the bus as a data byte instead of a command byte. This could be better identified by using a GPIB analyzer. However, it is quite odd that the DIR register makes such a significant impact. My guess is that the EOS character being written to the DIR causes the bus to send the next character as a command byte. There is probably some value that must be written to the chip to make the ATN line assert so the ? byte is sent as a command instead of data. http://ni.com/support/gpib/reg_prog.htm has a link to the 9914 manual.

Randy Solomonson
Application Engineer
National Instruments

[hdx]

Hello Randy!

Sorry about my English, I explaind the problem badly.

It is not the UNL "?" remote message I have problem with. Its when I send for example "IDN?" or "syst:err?". It is when a data message is sent and I have to recieve samething. I'm recieving everything correctly and after that everything just stops working as I described in the first post. Before I send the "?" data message everything works without problem.

Thanks!

RH

[Randy Solomonson]

ok. Try sending a data message that ends with the EOS character eg "*idn?\n". It might be time to attach some sort of analyzer to the GPIB bus. The PCI-GPIB+ card can capture the GPIB data to a file that would be very helpful in this case. Is there one available there? Maybe the local NI office can get one for you.

Randy Solomonson

[hdx]

Sorry! I dont have any kind of GPIB analyzer.
Thanks anyway!

RH