Rigol DS1054Z Pass/Fail Aux Pulse Output not working for me - Page 1
Forum section: electronics / testgear

author: bminear
author_rank: Newbie
timestamp: May 12, 2020, 10:27:46 pm
content: Hello, first time poster and electronics beginner after a career in software...anyway... Bought some lab test equipment including Rigol DS1054Z. I have a simple waveform coming in on CH1. Enabled the Pass/Fail functionality and created a mask that reflects a proper waveform range I want to see. When the waveform gets wonky and goes outside the mask the Rigol correctly detects it and updates the Fail/Pass/Total statistics accordingly. I know I have the mask proper because the stats are working perfectly. I then enabled the Aux Out for the Pass/Fail, which according to the scope documentation is to output a "negative pulse" whenever there is a fail condition triggered. I connected a BNC cable from the Rigol's trigger out on the back of the unit to another piece of test equipment to simply count the failures. But the output line always just measures 0v. So to debug this I just looped the Trigger Out BNC to CH4 on the same Rigol scope, and sure enough the signal just stays flat at 0v even during a fail condition, there is never a "negative pulse" being output. I'm sure I'm just doing something wrong, but can't figure it out. Any pointers is appreciated. The attached picture shows the failed waveform (CH1) and the supposed Pass/Fail Aux Out (CH4) using a BNC cable from the back of the unit around to the front.

author: maelh
author_rank: Regular Contributor
timestamp: November 07, 2022, 04:25:14 pm
content: I just experimented with the same scope and functionality, and I get a 520mV DC signal while the test passes (signal stays outside blue mask). When the test fails it has a much thinner line and is at 0V. Pass signal is about 720mV if you add a 50 Ohm termination before the scope input.Since your line is thick but seems to be at 0V or close to it, maybe there is an issue with your BNC cable? The DC line you see on the scope should definitely become slimmer when the test fails, like a pixel line thin (though not fully straight).See attachments for details.

author: maelh
author_rank: Regular Contributor
timestamp: November 07, 2022, 04:41:40 pm
content: With more testing I saw that there is an interaction with the trigger function and the pass/fail function. So if you trigger on channel 4 you wont see the change for some reason, the beeper still works, though.It makes sense the scope would get confused, since the mask stays put, so if the signal (here channel 1) is not triggering it will likely fail the test (in the case of a sine wave it obviously would due to the phase shift compared to the mask).Your best bet is to record data instead of triggering on channel 4 to see what the signal looks like.Yeah, it's definitely related to the trigger function, since the BNC on the back is also trigger out, and when you have no pass/fail functionality enabled it always shows a sharply rising edge at the trigger point, i.e., on the set x-axis/time-axis trigger location.So it likely checks at each trigger if the mask and the currently captured waveform match or not, and if not couples it out to the trigger.You can actually see that if you switch "Aux out" on, the normal trigger signal disappears and it will stay at 0V.I suppose the best option is to use a secondary/independent scope to see the aux signal.