Yogesh Bhanu
2021-Feb-26 03:50 UTC
[Nut-upsuser] Tripplite SMX1000LCD input Voltage reporting
Hello all, I have a Grid Overvoltage issue in my Area 'cause of solar inverter. Unfortunately the Tripplite ups underreports the input voltage -- It happens with the Display Panel and with SNMP. I 'm aware that with SNMP I'm polling the system. So I can never measure instant input Voltage. I'm polling at 3s interval without an issue. I have tested this with a Wattmeter and a Fluke Digital meter. The input voltage is off by alteast 3 - 5 V. So when the UPS reports 250.5 V or 251 V the input voltage usually is between 253.5 and 255V and this is the case when the grid input Voltage is high for 10s at which point Solar inverter resets. My question is, Is it possible the UPS Display is not reporting Instant input Voltage ? Kind Regards, Yogesh -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://alioth-lists.debian.net/pipermail/nut-upsuser/attachments/20210226/a645ba8b/attachment.htm>
David Zomaya
2021-Feb-26 04:30 UTC
[Nut-upsuser] [EXTERNAL] Tripplite SMX1000LCD input Voltage reporting
>> Is it possible the UPS Display is not reporting Instant input Voltage ?I can get some data to confirm either tomorrow or next week when I am in the office. So I make sure I am doing an apples to apples check, can you get me the first 13 characters of your serial number? Thank you, David Zomaya Tripp Lite ________________________________ This message is for the addressee's use only. It may contain confidential information. If you receive this message in error, please delete it and notify the sender. Tripp Lite disclaims all warranties and liabilities, and assumes no responsibility for viruses which may infect an email sent to you from Tripp Lite and which damage your electronic systems or information. It is your responsibility to maintain virus detection systems to prevent damage to your electronic systems and information.
Gene Heskett
2021-Feb-26 05:45 UTC
[Nut-upsuser] Tripplite SMX1000LCD input Voltage reporting
On Thursday 25 February 2021 22:50:05 Yogesh Bhanu via Nut-upsuser wrote:> Hello all, > > I have a Grid Overvoltage issue in my Area 'cause of solar inverter. > Unfortunately the Tripplite ups underreports the input voltage -- It > happens with the Display Panel and with SNMP. I 'm aware that with > SNMP I'm polling the system. So I can never measure instant input > Voltage. I'm polling at 3s interval without an issue. > > I have tested this with a Wattmeter and a Fluke Digital meter. The > input voltage is off by alteast 3 - 5 V. So when the UPS reports > 250.5 V or 251 V the input voltage usually is between 253.5 and 255V > and this is the case when the grid input Voltage is high for 10s at > which point Solar inverter resets. > > My question is, > Is it possible the UPS Display is not reporting Instant input Voltage > ?Its entirely possible since the invertor may take liberties with the waveform delivered, combined with whatever meter you are using's faithfullness to true rms response. With the more squareish waves output by an invertor, the measurement errors can exceed 10%. Bear in mind that most so called rms metering, is only truly accurate at 60 hertz, or 50 hertz depending on the environment its meant to be sold into. The only true way to find out where the error actually lies, is to look at the invertors output with an oscilloscope, but even the eye can be confused if the distortion is seemingly well filtered, in which case a comparison with the sine wave output of a Good audio test oscillator can be informative. See a good explanation for the term rms, which stands for the square Root, of the Mean of the of Sum the squares, which is a fancy way of saying how much heat is generated by a suitable resistor hooked across the src. One massive enough that its temperature is not pulsing from the frequency of the applied voltage which will effect its resistance. This is very difficult to do in a modern digital multimeter because to do it right, they would have to do all that squaring and adding for a complete cycle, or about 6000 times a second, then on the zero crossing, instantly calculate the square root of all that to display it. Doing that, given the power src for such a meter making those claims is a 9 volt battery expected to last 6+ months, is patently impossible. I just bought a new scope, a 4 trace, 350 MHz rated, 2GHz sampler by Siglent, that may be able to do that. It certainly has the horsepower to do it, but I've no clue if the code has been written to do it. Your other choices are a bolometer, generally used for signals above 500 MHz, or calorimetric involving measuring the temp rise of the water cooling the resistor, meaning 2 very accurate thermometers, and some means of measuring the water flow, all accurate to .1 degree and .1% flow. If its being a PITB, I believe I'd see if the invertor output could be turned down 1 or 2%. But if the scope says it outputting a square wave, flat across the top and bottom, I'd yell at the invertor maker. Its a BBLB invertor, so expect some additional expense for a smarter one.> Kind Regards, > > YogeshGood luck Yogesh. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene>