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Oscilloscope EXT. INPUT , source Channel#2

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Just a guess.
400 / 60 = 6.6666…
Maybe the oscillator that makes the 400 Hz has nothing to do with the 60 Hz so it wouldn't ever sync.
 
Maybe the oscillator that makes the 400 Hz has nothing to do with the 60 Hz so it wouldn't ever sync.

Yes it has nothing to do with eachother

At work there is 2 different wall main line outputs

You either plug equipment into a 120VAC at 60hz
Or you plug equipment in to the wall at 115VAC at 400hz

Two different line main frequencys
 
Billy, let's look at the attached image. SOURCE is used to determine the trigger source.
**broken link removed**
Now what do you see for SOURCE? For this particular scope I see CH1 (Trig off CH1 signal), Vert Mode (Trig of channel being displayed in vertical mode), CH2 (Trig off CH2 signal) and finally EXT for an external trigger signal. Note the shaded gray area for external which now includes LINE where the trigger source is the line frequency the scope is powered from, EXT / 10 where the external trigger signal input to BNC connector level is divided by 10, EXT where the external trigger signal into the BNC connector is used, and EXT Z which we won't get into but Z is the Z axis or intensity on the CRT. That is it for source.

Now if the scope is plugged into 60 Hz and we select EXTERNAL and LINE then our trigger signal is now 60 Hz. The scope will indeed trigger, however, there is no way you will obtain a stable display with a 400 Hz. signal displayed. You will have triggering but.... NO SYNCHRONIZATION. A 60 HZ trigger signal will trigger (with sync) a 60 Hz waveform or multiple of 60 like 120 or 240 or 480 HZ. The opposite is also true. Plug the scope into 400 Hz. power and choose a line source the scope will trigger but you will not be able to synch for example a 60 Hz signal. You could synch 400, 800 1.6 KHz and so forth.

Got It?

Ron

Trigger Section.png
 
Yes kinda.

My O-scope is plugged into 120vac 60hz.
My test fixture is plugged into 115vac 400hz

all the outputs signals of the test fixture are sync to 400hz not 60hz

how do I trigger and sync the scope to the test fixtures output signals?
 
A. Trigger using External trigger using 400 Hz. We have been over this. I don't have your scope sitting here so I don't know your options on your scope.
B. Trigger off the signal you are looking at. For example choose CH1 for the source and probe around looking at your signal on CH1. Using the above example SOURCE = CH1, MODE = P-P AUTO, SLOPE = + and LEVEL about mid range for starters.

There are options so pick one.

Ron
 
all the outputs signals of the test fixture are sync to 400hz not 60hz how do I trigger and sync the scope to the test fixtures output signals?

Also, exactly what do these signals look like? What are the signals?

Ron
 
AC signals they look like AC waveforms, they must be synced only to 400hz not to 60hz

The AC signals are at 26vac at 400hz hooked up to gyros and syncos motors

my question is why can't u sync 60hz with 400hz?

why do i have to use the triggering and sync?
 
AC signals they look like AC waveforms, they must be synced only to 400hz not to 60hz

The AC signals are at 26vac at 400hz hooked up to gyros and syncos motors

my question is why can't u sync 60hz with 400hz?

why do i have to use the triggering and sync?
20 JOBS as a Test Technician!! and i am not allowed to call it as it is!!! No wonder ADULTS start war's. Your name should be Billy Bollox.
 
I am sorry , but this thread is totally beyond belief.

Someone who is supposed to be some kind of test/repair technician is posting questions to enable him to do his work.
The questions, if taken at face value, would infer that the technician is unable to do his job without the answers to those questions.

If this is all work related, why cannot someone within the company take the time to demonstrate and explain to the technician the correct way to perform the tests.

Kudos to those who are attempting to give sensible answers to this, and related threads but I fear that you are "casting pearls before swine".
In a similar styled thread which related to PIC programming, the tireless responder opined that while his answers may not be fully understood by the originator of the thread, they would form a knowledge base for others.
That may be true in that case as well as this one, but as a casual observer of this thread, it was amusing at first but now it hurts to see good effort being wasted like this.

JimB
 
I am sorry , but this thread is totally beyond belief.

Someone who is supposed to be some kind of test/repair technician is posting questions to enable him to do his work.
The questions, if taken at face value, would infer that the technician is unable to do his job without the answers to those questions.

If this is all work related, why cannot someone within the company take the time to demonstrate and explain to the technician the correct way to perform the tests.

Kudos to those who are attempting to give sensible answers to this, and related threads but I fear that you are "casting pearls before swine".
In a similar styled thread which related to PIC programming, the tireless responder opined that while his answers may not be fully understood by the originator of the thread, they would form a knowledge base for others.
That may be true in that case as well as this one, but as a casual observer of this thread, it was amusing at first but now it hurts to see good effort being wasted like this.

JimB

Compare your sentiments to those in posts #4 and #5 here:

https://www.edaboard.com/thread305233.html
 
Billy, An oscilloscope's trigger function is crucial for clear signal characterization because it is what synchronizes the horizontal sweep at the correct point of the signal. Trigger controls allow you to stabilize repetitive waveforms and capture single-shot waveforms. As a technician I would expect that to be understood. That alone should tell you why using oscilloscope triggering you can't synchronize a 400 Hz. signal with a 60 Hz. signal.

At the company I just retired from when we selected new technicians (electrical) they were expected to come through the door for their initial interview with an at least associate degree in one hand and their grade transcripts in the other hand. They were expected to clearly demonstrate a working knowledge of basic electronic theory plus the ability to demonstrate the proper use of lab test, measurement and diagnostic equipment. I then expected the senior technicians in my charge to train them on our product line.

This is truly a great forum but people are expected to help themselves. Questions are always welcome but any topic can only be taken so far. Oscilloscope basics likely involves 40 hours of classroom and lab instruction, that simply can't be accomplished within this or any online electronics forum. This forum has a great set of resources including videos. You may want to use them. I am done with this thread as we aren't getting anywhere. Maybe another member will be more help to you than I can be.

Ron
 
Compare your sentiments to those in posts #4 and #5 here:
OK enough said!
JimB
 
Now if the scope is plugged into 60 Hz and we select EXTERNAL and LINE then our trigger signal is now 60 Hz. The scope will indeed trigger, however, there is no way you will obtain a stable display with a 400 Hz. signal displayed. You will have triggering but.... NO SYNCHRONIZATION

Yes True, but why no synchronization? because the O-scope horizontal is at 60hz so it can find a start point? why can't it obtain a stable display? is it because the O-scopes horizontal beam is defaulted at 60hz right? so when you apply a 400hz SOURCE this changes the O-scopes horizontal beam to 400hz not 60hz right?

What's the difference between triggering and Sourcing?

Sourcing is the synchronization , the O scope is defaulted at 60hz, the horizontal bean circuit is going across the display at 60hz

A 60 HZ trigger signal will trigger (with sync) a 60 Hz waveform or multiple of 60 like 120 or 240 or 480 HZ. The opposite is also true. Plug the scope into 400 Hz. power and choose a line source the scope will trigger but you will not be able to synch for example a 60 Hz signal. You could synch 400, 800 1.6 KHz and so forth.

Yes True, But why is that? look deeper into why

The 60hz is like a clock signal and the 400hz is like a clock signal right? its frequency

If I brought you a circuit board and had 10 outputs waveforms and I didn't tell you what the line or sync frequency was , how would you know what to SYNC , SOURCE, TRIGGER the O -scope to?

You would first measure the frequency/time of the waveform? but how would you find out what the SYNC frequency is?

Since the O-scope is defaulted at 60hz, all the waveforms would be Free Running because you don't know what the waveforms are SYNC to.

How would you find out what the signals that are periodic with a period that is related to that SYNC frequency? the frequency/time of the waveform is not the Sync frequency

The Sync frequency is an external signal

How would you find out the external signals frequency without me tell you what is it?

I suppose it because you want to look at signals that are periodic with a period that is related to that 400 Hz.

Yes I do,

The Periodic or time period at 400hz is different than a time period at 60hz

The SYNC frequency ( external signal ) is like a clock right?

The Time and frequency of the signal can be different than the SYNC frequency ( external signal )?

The Waveform is superimposed on top of the sync frequency ( external signal ) ?

Before you go any further, find out for sure if the 400 Hz main and the 60 Hz main at your work are single phase mains that have one leg tied to ground. I know that a typical 120-volt main in the USA consists of a neutral leg that is connected to ground somewhere and a hot leg that is 120-volts with respect to that neutral. But I don't know about your 400-volt feed. It might be the same sort of thing, or it might be a floating power feed from a transformer. Until you find out for sure which it is at your work, you cannot safely connect the 400 Hz main to the EXT of the scope.

Ok this I will have to try to find out at work if they know the answer, but the 115VAC at 400hz is a 3 phase , I don't know if it's delta or WYE

The 115VAC at 400hz goes to a AC ratio step down transformer that outputs 26 VAC at 400hz , this goes to Gyros motors & Syncro motors

This is fine if the Function Generator is actually generating the same 400 Hz that is powering the 400 Hz line to the board under test. But if it is just some other 400 Hz that is not related to the 400 Hz on the board, it will not do any good, and the trigger will still appear free-running.

The function generators output is 400hz , it's the same frequency why won't it work? i don't get it?
 
What's the difference between a 1Khz waveform sync to a 60hz external signal VS a 1Khz waveform sync to a 400hz external signal?

Is the time period different? phase angle different? or what is different about the two?

It's the same frequency at 1Khz waveform , the only difference is the Sync frequency ( external signal )
 
my question is why can't u sync 60hz with 400hz?

Because 400 is not a multiple of 60.

Or, to use another non-electical example.
Q- Why does New Years Day fall on a different day of the week each year?
A- Because 365 is not a multiple of 7

You can't sync two frequencies unless they are exact multiples of each other. And why are you trying to do that anyway?

If you want to look at a 400Hz signal on Channel 1, just set your trigger source to be Channel 1. NOT LINE!!!
 
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i guess the gyro motors and synco motors need a 400hz sync , because of the power supply is not at 60hz it's at 400hz
But you just said that the frequency you are trying to measure was 1Khz.

What does 1Khz have to do with 400Hz?
 
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