EABO timeout on HP3784A BERT.

[Vijay Ramasami]

Hi,

I am having a hardtime talking to HP3784A (a rather old one). It is connected to my computer using GPIB-HS-USB cable. The NI GPIB Explorer can recognize the equipment and its GPIB address, but I am getting an EABO:timeout when I issue any commands.

On the instrument panel, I can see that the equipment is connected (the status changes between "Remote Listen" and "Remote Talk" whenever I send a command using the GPIB explorer), but the GPIB explorer always reports a timeout. The remote control error status in the HP equipment is 0 => no errors. Of course, if I send a random unrecognized command, the HP3784A properly reports it as an error implying that it is able to receive my commands properly, but the NI driver on my computer does not properly recognize the data sent from the HP3784A. I also used the "CLR" command successfully to clear BERT errors implying that the BERT is able to receive commands.

I have tried almost everything: using the NI Spy, and configuring the EOS settings in the GPIB explorer, but nothing has worked so far. The only thing I haven't tried so far is the 8-bit EOS compare because I don't know what byte to use for that.

The HP3784A remote control manual mentions this connections as HP-IB. So, wonder if there is any difference between GPIB and HP-IB ? (I thought they were the same, and the name HP-IB is deprecated ?). Has anyone experienced this problem before ? Any NI app guys in this forum that can help ?

Any help is greatly appreciated !

Thanks,
Vijay.

Application Engineer, Thomson Multimedia.

Message Edited by Vijay Ramasami on 04-18-2006 10:27 AM

[Vijay Ramasami]

Ok. Kinda figured it out myself ...

1.  ibdev(0, 5, 0 (0x0), T10s (13), 1, 0x040A)
ibsta: 0x100       iberr: 0             ibcntl: 0(0x0)

2.  ibclr(UD0)
ibsta: 0x100       iberr: 0             ibcntl: 4(0x4)

3.  ibwrt(UD0, "ID?..", 5 (0x5)) -> actual string sent was "ID?\r\n". It is displayed as "ID?..".
ibsta: 0x100       iberr: 0             ibcntl: 5(0x5)

4.  ibrd(UD0, "HP3784A..", 1000 (0x3E8))
ibsta: 0x2100       iberr: 0             ibcntl: 9(0x9)

It would be nice to add a note in the NI website and the GPIB explorer about older HP instruments and ways to communication properly with them ... ("\r\n" and 0x040A).

Regards,
Vijay.

[CPeterS]

Thanks to the landmark effort of Vijay I figured out on how to talk to that ancient beast.

I just have to add, that Labview does not treat the necessary \r\n as meta characters. 

The direct appending of the cariage return and line feed string constants does the trick, however. 

It also seems possible to use a GPIB write command with mode set to 6 (append CR and LF, 

don't sent EOI during LF). 

Nevertheless that old HP3784A makes You more grief, e.g. as it won't react on the now 

ubiquition *IDN? command. Thus You have to scan the bus using both *IDN? and  ID?<cr><lf>...

But given the fact, that You have to use that 3784A, You surely will find a way to deal with this. 

Best regards

Peter

STT Systemtechnik

[Dennis_Knutson]

LabVIEW does handle \r and \n if you configure the string control/constant. Just right click and select '\' Codes Display.