Author Topic: Rigol DS1054Z Software or Hardware Bug?  (Read 4684 times)

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Offline bitshift

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Rigol DS1054Z Software or Hardware Bug?
« on: December 29, 2015, 01:52:56 AM »
Hey guys,

I have a Rigol DS1054Z and I've been playing around with some filters today. I was comparing the output of the first filter on CH1 versus the output of the second filter on CH2. I was getting "strange" output on the second filter, so I made the second filter equal to the first filter and to my surprise, the output was not equal on the scope.

Scope version information:



CH1 @ 1V per division and CH2 @ 1V per division triggering off CH3. Math A-B is on at 1V per division.



CH1 @ 2V per division and CH2 @ 2V per division triggering off CH3.



CH1 @ 500mV per division and CH2 @ 500mV per division triggering off CH3. I forgot to turn the math function on here but the A-B operation reflects the difference between to the two wave forms.



Note the difference in wave form. The probes are physically connected to the same point in the circuit:



I first suspected probe compensation so I checked both probes:

CH1 compensation:



CH2 compensation:



CH1 & CH2 & CH3 compensation side by side @ 1V per division:




CH1 & CH2 compensation side by side @ 500mV per division:



Note the difference in amplitude of the square wave. I tried two different probes connected to channel 2 but the same issue was present. I tried the self calibration feature of the scope but again the problem persisted. Just to be sure, I then tried switching CH2 with CH3 and the results were correct.

CH1 @ 1V per division and CH3 @ 1V per division triggering off CH2.



CH1 @ 500mV per division and CH3 @ 500mV per division triggering off CH2.



This issue only happens when switching from 1V per division to 500mV per division and lower on CH2. I can't decide whether this is a hardware or software bug since there are no relay clicks when you change from 1V to 500mV per division. Any ideas on what the issue could be?



« Last Edit: December 29, 2015, 01:59:22 AM by bitshift »
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Offline Fungus

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #1 on: December 29, 2015, 02:06:58 AM »
This issue only happens when switching from 1V per division to 500mV per division and lower on CH2. I can't decide whether this is a hardware or software bug since there are no relay clicks when you change from 1V to 500mV per division. Any ideas on what the issue could be?

Might be something to do with the fact that the DS1054Z hardware doesn't support 500mV per division. You're not supposed to enable that 'feature'.
 

Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #2 on: December 29, 2015, 02:07:45 AM »
Might be something to do with the fact that the DS1054Z hardware doesn't support 500mV per division. You're not supposed to enable that 'feature'.

I believe that is 500uV not 500mV?
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Offline Fungus

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #3 on: December 29, 2015, 02:18:52 AM »
Might be something to do with the fact that the DS1054Z hardware doesn't support 500mV per division. You're not supposed to enable that 'feature'.

I believe that is 500uV not 500mV?

Oops.  :palm:
 

Offline Fungus

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #4 on: December 29, 2015, 02:21:42 AM »
Channel 2 is AC coupled so I expect to see a capacitor charge/discharge waveform like that. What is channel 1 set to?


« Last Edit: December 29, 2015, 02:23:17 AM by Fungus »
 

Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #5 on: December 29, 2015, 02:22:53 AM »
Both AC coupled. I didn't mention it but on both AC and DC coupling the result is the same.
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Offline Fungus

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #6 on: December 29, 2015, 02:33:46 AM »
What happens if you turn the 20MHz bandwidth limiter off?
 

Offline Mark

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #7 on: December 29, 2015, 02:39:25 AM »
What happens when you connect all the scope ground leads to ground and repeat the test? 
 

Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #8 on: December 29, 2015, 02:39:53 AM »
What happens if you turn the 20MHz bandwidth limiter off?

The same response is acquired. This is with no bandwidth limit and both channels DC coupled.

« Last Edit: December 29, 2015, 02:43:19 AM by bitshift »
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Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #9 on: December 29, 2015, 02:41:34 AM »
What happens when you connect all the scope ground leads to ground and repeat the test?

No difference
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Offline Orange

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #10 on: December 29, 2015, 02:45:15 AM »
Interesting puzzle.

It could be a faulty CH2 on your scope. It could also be a faulty CH2 probe.

Have you tried swapping the CH1 <> CH2 probe at the scope BNC connector ?
 

Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #11 on: December 29, 2015, 02:46:44 AM »
Interesting puzzle.

It could be a faulty CH2 on your scope. It could also be a faulty CH2 probe.

Have you tried swapping the CH1 <> CH2 probe at the scope BNC connector ?

I tried swapping the probe from CH2 with CH1 and the again with CH3 but in both cases the problem remained.
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Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #12 on: December 29, 2015, 02:50:00 AM »
Channel 2 is AC coupled so I expect to see a capacitor charge/discharge waveform like that. What is channel 1 set to?

Just for more context, CH1 and CH2 are the outputs of a filtered PWM signal. I'm trying to visualize the response of two different filters (but in the screenshots it's the same filter) to a step in the PWM duty cycle. CH3 is only a reference output so I can cleanly see when the PWM duty cycle changes. CH3 is not connected to CH1 and CH2 in any way.
« Last Edit: December 29, 2015, 02:51:39 AM by bitshift »
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Offline Orange

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #13 on: December 29, 2015, 02:52:12 AM »
Interesting puzzle.

It could be a faulty CH2 on your scope. It could also be a faulty CH2 probe.

Have you tried swapping the CH1 <> CH2 probe at the scope BNC connector ?

I tried swapping the probe from CH2 with CH1 and the again with CH3 but in both cases the problem remained.
I think your scopes CH2 hardware is damaged on the lower range. Probably a compensation C disconnected/open in the front-end.

 

Offline Fungus

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #14 on: December 29, 2015, 03:00:38 AM »
I think your scopes CH2 hardware is damaged on the lower range. Probably a compensation C disconnected/open in the front-end.

I agree.

It's a capacitance curve, something has a lot more capacitance than it's supposed to have. If it's only channel 2 then channel 2 is broken.

Do a factory reset to make sure it's not some obscure configuration. If it's still there then send it back.


 

Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #15 on: December 29, 2015, 03:09:05 AM »
Did a factory reset and the issue persists. I guess its time to test if Rigol will honor the warranty with the hacked firmware.

Thank you all for your help  :-+
« Last Edit: December 29, 2015, 03:55:33 AM by bitshift »
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Offline alsetalokin4017

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #16 on: December 29, 2015, 03:36:53 AM »
Remove the "hack" before you send it back !!  (And just for completeness sake, retest for the problem after you've removed the hack.)

:SYSTem:OPTion:UNINSTall

sent to the scope using your favorite method of sending SCPI commands.

The easiest person to fool is yourself. -- Richard Feynman
 

Offline Fungus

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #17 on: December 29, 2015, 04:00:08 AM »
Did a factory reset and the issue persists. I guess its time to test if Rigol will honor the warranty with the hacked firmware.

You can remove the hack... use an ethernet cable and install the Rigol software on the CD.

There's a command-line thingy in there somewhere. Open it and do ":SYSTem:OPTion:UNINSTall"
 

Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #18 on: December 29, 2015, 04:06:04 AM »
Thanks all  :-+

Just did a reset so back to a 1054Z. I tested again and the problem is still there. I will get hold of the dealer tomorrow and arrange for the unit to get sent back.
"It’s all fun and games until an innocent opamp gets hurt!" - Dave Jones
 

Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #19 on: January 14, 2016, 06:59:34 PM »
I took the scope to the dealer and they checked it out and let me know that Rigol said they would give me a brand new unit. I received a unit today but the box was a little beat up/opened already. I'm skeptical that it is indeed a new unit. Is there a way I can lookup when the unit was manufactured or released based on the serial number?
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Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #20 on: January 14, 2016, 10:39:21 PM »
Further to the above, would it be wrong for me to insist on a sealed unit? I haven't had to time to inspect the instrument yet. I will do so thoroughly once I get home from work.
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Offline Fungus

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #21 on: January 15, 2016, 12:38:08 AM »
Further to the above, would it be wrong for me to insist on a sealed unit?
Rigol is under no obligation so long as it's in at least as good condition as the one you returned.

(and the alternative might be to wait months for your personal 'scope to be fixed).

 

Offline bitshift

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #22 on: January 15, 2016, 01:02:14 AM »
Understood, thanks. My inner skeptic took over for a while :scared: Busy testing the scope now and all seems perfect.
"It’s all fun and games until an innocent opamp gets hurt!" - Dave Jones
 

Offline fivefish

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Re: Rigol DS1054Z Software or Hardware Bug?
« Reply #23 on: January 15, 2016, 01:42:25 AM »
Good to hear.

I guess its time to test if Rigol will honor the warranty with the hacked firmware.

And to answer your question, YES. 

When you get back the scope, the hack isn't there though, but you'll have the latest firmware.
Just re-apply the hack. :)

 


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