Trigger Delay Problems Agilent 34401

[Weippert]

Hello,

I want to trigger my Agilent 34401 with an external trigger and a trigger delay.
The external trigger is a Function Generator with a frequency of 1.000 kHz. The signal, that shall be measured, is DC (5 V), because with a sinussignal I get shifted values. For example I had a signal with a period of 2 seconds and the Agilent 34401 measured at 400 ms (trigger delay of 400 ms) a higher Voltage value, than at 500 ms (usually the point with the highest Voltage). The synchro-out was the external Trigger and the signal was from the same generator. I use DC now to test, but I want to use different signals later.
A further problem is, that I get the error -410,"Query INTERRUPTED" when I use longer trigger delays, because it doesn't react, and when I click again I get a beep-signal and this error message. With short times it usually works, but sometimes I get the same error-message.
I send you the VI, which I use. (The SCPI-Code is already in the command-(Befehl)-line.)
I hope you can help me.
Answers are preferred in German, but English is OK, as well.

Greetings M. Weippert

[Jim Piotrowski]

Hi!

The reason you're getting a Query Interrupted error is because you're sending several commands in a row that each require a VISA read.  Specifically, READ?, TRIG:DELAY? and SYST:ERR? all need a write DIRECTLY before another command is given or else it will throw a Query Interrupted error.

About the shifting, I tested a signal of the same characteristics and found that the voltage to be at 5V with a .5 s delay.  If you tell me what version of LabVIEW and which driver you're running, I may be able to look into it further.

[Weippert]

Hello,

but if I use times till about a second it usually works without bigger problems. The problem usually starts at longer times (>3 seconds). Nevertheless I will try your proposals.
I have LabVIEW 8.0.1 professional. Which driver do you mean?

Greetings M.Weippert

[Jim Piotrowski]

Under Instrument I/O->Inst Drivers in the Functions Palette, there should be a 34401A instrument driver.  With that, you should be able to do pretty much anything the DMM itself can do.

However, for your specific issue, you might try creating a property tab for the VISA connection and lengthening the timeout.  This is especially true if you're working over a serial connection.

Anyway, hope this helps!

[Weippert]

I have lengthen the VISAt-timeout (20 seconds) and now I can use also longer Trigger-Delays. But now I have the problem, that it takes for this command:
*RST;:CONF:VOLT:DC;:TRIG:SOUR EXT;:TRIG:DELAY 2.5;:TRIG:DELAY:AUTO OFF;:INIT;:READ?;:TRIG:DELAY?;:SYST:ERR?;
9 seconds, although I have only a Trigger delay of 2.5 seconds. The answer for this command is:
+4.88885300E-03;+2.50000000E+00;+0,"No error"

The problem is, that the Function Generator creates a Sinussignal with a frequency of 1 kHz and a Voltage of 8 Vpp. So I should have about 4 V and not only 4,88 mV.
When I use lower frequencies (like 500 mHz) the measured Voltage is higher (almost 4 Volt when I use a delay where a Voltagemaximum should be), but for example I get at a frequency of 500 mHz a higher Voltage with a Triggerdelay  of 400 ms, then with a Triggerdelay of 500 ms (which is the Voltagemaximum).

What can be the problem of the very long execution of the command and the strange measured values?

I would be glad, if you could help me.