Timeout error, LabView 7.1 and HP34970A DAQ Module using RS-232

[p3ppit]

Hi there.

I am running a VI, that is setup to perform the following operations with the hardware listed below:

- MSWIN 2000 Desktop PC

- HP/Agilent 34970A DAQ/Switch Module w/ a 20 channel general purpose switch/relay card (Operation: NO ~ Normally Open) and a 16 channel reed multiplexer card installed

- Standard RS-232, Baud: 57600, XON/XOFF, No parity bit + 8 data bits. (all the default factory settings)

The VI:

Read and log voltage measurements from 4 channels on the multiplexer card. (Using a subVI called HP34970A EZ Voltage)

Wait 1 sec.

Close 2 relays for 6 seconds (Again using a subVI downloaded right here from NI to use with the 34970A Instrument)

Read and log voltage meas again.

Open the said relays for 14 seconds.

These operations are done in a for loop 1440 times = 8 hours of operation.

Now... Here's my issue:

When the VI has run approx. 840 times I get the following error:

Error- 10[.....] occured at VISA READ.

Possible reasons: Visa hex =x[.......]

Timeout expired before operation complete.

This irks me... Because I am only reading 65 bytes at a baud rate of 57600 = ~9-10 msec right?

The default timeout of the initialization VI to use with my HP34970A is 10000 msec, so I don't see an issue with that.

If anyone could lead me in the right direction it would be greatly appreciated.

Thanks in advance,

//Per

[Albert.Geven]

probably a hickup in the agilent reading
build a retry inside your loop.

[p3ppit]

Hi Albert,

Thanks for the quick reply.

I ended up simply adding a general error handler to my block diagram, comparing the error I got with a constant (same error code) and just ignoring the error to let the VI run execution.

Simple reason: I am fairly new to LabView and this was easier IMHO than trying to implement a retry function + the fact that I can live without a single scan not being logged.

Fingers crossed, I hope this is sufficient, else I will look into your proposal.

//Per 

Message Edited by p3ppit on 12-13-2007 09:15 AM