SCOPE not triggering on negative levels and negative slopes in Soft Front Panel

[jona.hernandez]

The PXI-5122 has been working intermittently when set to trigger on a negative level and negative slope in a SGL shot mode. 
I'm wondering if any of the users have see this issue.  Here is how I troubleshot the issue. 

HARDWARE
----------------
PXI - Quiet Chassis
PXI - 8105 (BTW this $4k controller does not boot when the USB ports are loaded down?)
PXI - 5122

SOFTWARE
----------------
NI-Scope 3.3.2
LV 8.5
TestStand 3.5

System was configured by FIS in Nov/Dec of 07

In SFP (S-oft F-ront P-anel), I set the 5122 to trigger as follows

Level: -20mV 
Slope: Negative
Mode: SGL
Source: CH1
CH1 Volt Range:  4V

When the 5122 is set with the above configuration, I click on the "Run" button.  Shortly after (1 or 2 seconds later)
I fire the trigger.  The trigger signal swings between 1.2V to -1.2V (source velocity sensor).  The good news is this will work
most of the time, but every now and then  the 5122 decides that it will stop triggering.

When this happens, I go back into SFP to investigate and I get the same issue.  5122 does not work consistently triggering using the same
settings and procedure above.

I then take a look at the Measurement and Automation Explorer, MAX, test panels. I confirm that the trigger signal swing between 1.2V and
-1.2V.  I also set up the triggering scheme above in MAX test panels and I get consistent results.  In other words the SCOPE will trigger
using the above settings consistently; however, only in MAX test panels.  I am wondering why SFP is not consistent?

I would assume that MAX uses the same SCOPE drivers as SFP and the NI canned SCOPE examples.  If this is true, why would SFP not work
as well as MAX test panels?

Currently, the system is function.  I am nervous about the 5122 and and have lost confidence in the NI SCOPE line because of these intermittent triggering issues.

I have a FLUKE hand held SCOPE and a legacy TEX 2122 and they both trigger consistently using the same settings above.  Can anybody
explain why the premium priced 5122 would miss triggers?

[hoffiz]

Hi

I’ve been working with the exactly same setup, I have been able to fire the trigger multiple times with no miss trigger and I may say I tried it at least for one hour, I have tried waiting a long time for the trigger, SGL mode, Normal MODE, falling edge, rising edge, etc. Any possible configuration, I did it here in my test machine.

The only thing I have seen that might help you is that if you set the mode for single shoot on the Soft Front Panel you can see it goes to “pause” right after the trigger is received; and it will no be waiting for any more triggers; something that is not happening on “test panels”. Also make sure you are not pressing the “auto setup” button since it will change to default state the configuration of the SFP.

These are a couple of things you get when you buy a 5122: Digitizer/Oscilloscope Fundamentals.

I hope it helps

Message Edited by Jaime F on 02-01-2008 11:02 AM