Trace Dumps For HP 8757D Need To Enable / Disable EOL String

[Johnnie]

I am trying to get trace data from the HP 8757D network analyzer. I have no problem with any of the other 8757 operations.

I command the analyzer to send the data and I receive the data OK. All other communication with the device stops there until I send a bus clear and device clear.

The HP "programming guide" was written for an HP GPIB card and has an example where just before the trace dump input command, they call the "IOEOL" function with the arguments (busid, endline, 2) (endline is a two character buffer that contains 13 and 10 (cr and lf)). The comment with this line is "Disable the end-of-line string (cr/lf) that is sent after any IOOUTPUT command." They also call this function just after IO
OUTPUT function call, but the comment now says, "Enable the ....".

I am trying to determine what the equivelent National Instruments GPIB command is for this HP IOEOL function. Are they sending the cr and lf to the unit? No I don't thik so since they are only addressing the bus, not the unit. I have been talking to HP without success yet. They seem to think that I simply have to send a cr / lf to the bus, but so far that has not worked.

If there were a driver written for the 8757D, I am sure that it would cover this issue, but I can't find one on the web site. Can you help?

Thanks in advance.

Johnnie

[Rob Cole]

This sounds like the same problem that I ran into with our HP8753E network analyzer. The solutiion that I finally came up with is to set my read function for 1 more byte than the trace data is supposed to have. the network analyzer sends all the trace data in the buffer before going on to other tasks, so if you leave even 1 byte in the buffer, the analyzer continues to wait to send. Try receiving extra data and ignore the "extra" character(s) when processing the trace data.

Hope this helps.

Rob