HP 54624A Oscilloscope - Page 1
Forum section: electronics / testgear

author: rcowboy78
author_rank: Contributor
timestamp: August 02, 2018, 06:33:22 am
content: Okay either I'm a big dummy or there is something wrong with my scope.The vertical scale is inverted. Moving up the vertical scale, I have negative values. (-1V, -2V, -3V, etc) Move down the vertical scale I have positive numbers (1V, 2V, 3V, etc) So it's like the X-Y axis is upside down, except the horizontal is correct.I do not have the invert function turned on.I have tried setting the scope to default settings, but that doesn't change a thing. Still same problem. I have flipped through the manual for quite some time and can't find any settings that would cause this.I'm stumpedAny HP scope experts have any ideas?Thanks,rcowboy78

author: bitseeker
author_rank: Super Contributor
timestamp: August 02, 2018, 06:36:13 am
content: Photos? Is the on-screen text flipped, too?

author: rcowboy78
author_rank: Contributor
timestamp: August 02, 2018, 06:56:18 am
content: No, the on-screen text is not flipped.If you apply a +3V DC input into the scope the trace falls into the negative range of the y-axisIf you apply a -3V DC, it rises into the positive range.See the attached images. This is me using the vertical scale adjustment. Up is negative as per the upper right hand corner value indicator, and moving the trace down is positive.Thanks for the help,rcowboy

author: rcowboy78
author_rank: Contributor
timestamp: August 02, 2018, 06:58:52 am
content: It's like this on all 4 channels. I also tried to see if there was a way to change the reference, but I don't see that anywhere in the scope as an option.Thanks,rcowboy

author: bitseeker
author_rank: Super Contributor
timestamp: August 02, 2018, 07:14:30 am
content: Quote from: rcowboy78 on August 02, 2018, 06:56:18 amDo you mean you're using the vertical position adjustment? The value displayed briefly when adjusting the position indicates how far the ground reference is from the center of the screen.Try this. Ground the input of channel 1 and use the vertical position to set the trace to the center of the screen. Then, input the +3V DC into channel 1. Does it appear above the center?

author: MarkL
author_rank: Unknown
timestamp: August 02, 2018, 12:51:59 pm
content: I'm guessing the bar over the channel number in the upper left corner means invert is on.What happens if you try to enable invert from the menu?Bad memory? Stuck latch?

author: JFJ
author_rank: Regular Contributor
timestamp: August 02, 2018, 01:46:52 pm
content: Quote from: rcowboy78 on August 02, 2018, 06:33:22 amWas that a complete oscilloscope reset?From the service guide:"To reset the entire oscilloscope, press and hold any softkey and switch theoscilloscope power on. Release the softkey when the display appears".

author: rcowboy78
author_rank: Contributor
timestamp: August 02, 2018, 03:32:57 pm
content: QuoteYes, I was using the vertical position adjustment. You are correct, the value displayed briefly when adjusting the position indicates how far away I am from the ground reference. However the value displayed briefly is a negative value, and not positive when moving the position up into the positive range. When I apply a positive DC value, (3VDC) the trace does move into the positive range.QuoteYes, you are correct. In that image I do have the invert enabled. However disabling it has no effect. All it simply does is invert the waveform as normal. When I took the image, I forgot to disable it. The brief display of the vertical scale value still suggest that up is negative with respect to ground, and moving down the vertical scale is positive. Is there anyway to invert the reference where positive is up and negative is down?QuoteI tried doing this, but I get no response from the scope when trying to do a hard rest. It just starts up as normal. There must be a specific key.

author: rcowboy78
author_rank: Contributor
timestamp: August 02, 2018, 03:49:47 pm
content: It's not a show stopper, I can use the scope. Quite frankly I've been using this scope for quite some time and just now noticed it. I've got 2 other similar scopes in the HP 54 series family. A 54616 and a 54615 They do not do this. When the value is briefly displayed, up is positive and down is negative. I just can't figure out why this one is the complete opposite. Just threw me for a loop last night. Make you think your going crazy, you know.

author: oPossum
author_rank: Super Contributor
timestamp: August 02, 2018, 04:10:50 pm
content: This is normal behavior for 5462x series. It is showing what has to be added to the graticule reading. There is nothing wrong with the 'scope and I don't think this behavior is changeable.

author: bitseeker
author_rank: Super Contributor
timestamp: August 02, 2018, 04:13:23 pm
content: Yeah the scope seems to be displaying the trace as expected. The signal is not inverted. It's just the vertical position offset value that appears inverted. Odd.