AXIOMET AX-155 - Page 1
Forum section: electronics / testgear

author: jonasssss
author_rank: Newbie
timestamp: August 27, 2013, 03:51:07 pm
content: Hi! Could someone provide me some information about AXIOMET AX-155 multimeter. 1. What's the frequency range which it maintains RMS sensing for? 2. Is it capable of measuring duty cycle?

author: Lightages
author_rank: Unknown
timestamp: August 27, 2013, 04:36:23 pm
content: QuoteWell it appears that Axiomet does not supply information about the TRMS specifications on their webpage:http://www.axiomet.eu/files/htmls/EN/ramka_4893_EN_pelny.htmlIt does not say anything about duty cycle. It is probably made by CEM but I cannot find a corresponding model from CEM.Maybe somebody here has one and can look in the manual to see if there are any specs.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 06, 2013, 12:54:56 pm
content: It samples 2 times/sec so I do not think it will be TRMS and I do not think the crest factor will be high. But I'm not so digital. My benchmeters become more stable and more digits if I increase the sample time, but I think that means that it takes more samples, calculate the avarage and then displays it. That AX-155 only makes two samples in a second. I think that means it needs more as a second to show an AC signal that is 50Hz. But I see no refresh rate.Funny, never thought about this. I will look if I can find the samples/sec for one of my TRMS meters (some measure upto 1 MHz AC and some do AC+DC, many RMS meters are AC coupled so give wrong readings if the signal has a DC offset)

author: Unknown
author_rank: Unknown
timestamp: September 06, 2013, 02:58:13 pm
content: Except for the HP 3458A, the recent Agilent bench meters (eg. 34410A) and maybe some other modern bench meters, most true-RMS meters use an analog converter from an AC signal to a DC voltage equal to its true RMS voltage. In older meters (eg. HP 3455A) this was a thermal converter where they directly measured the heating power (somewhat similar to some RF power meters), and in more modern meters it might be an AD637. The ADC can then sample this DC voltage at its own pace. So the sampling rate of the ADC is pretty much independent of the AC bandwidth. Bandwidth depends on the true RMS converter (some thermal onces went up to 1 MHz) and the front-end.My guess is that the bandwidth of this would be a few kHz at best. The Axiomet page does not mention duty cycle, and I don't see any buttons or display annunciators suggesting that it can measure duty cycle.

author: PA4TIM
author_rank: Super Contributor
timestamp: September 06, 2013, 04:48:30 pm
content: My analog ancient HP-3400 goes up to 10MHz and every time I use it I am impressed how accurate this thing is and the resolution you can get. It is one of the few analog meters in my collection I also really use.

author: retiredcaps
author_rank: Super Contributor
timestamp: September 06, 2013, 06:29:06 pm
content: Quote from: Lightages on August 27, 2013, 04:36:23 pmCEM DT-9918http://www.cem-instruments.com/en/pro/pro-469.htmlNo manual on their website though.PS. Also sold on Amazon.comhttp://www.amazon.com/CEM-DT-9918-Waterproof-Multimeter-Capacitance/dp/B008SODGT2/ref=sr_1_3?ie=UTF8&qid=1378492013&sr=8-3&keywords=cem+dt-9918

author: elliott
author_rank: Regular Contributor
timestamp: September 06, 2013, 09:07:46 pm
content: Looks like the Extech EX505 as well.http://extech.com/instruments/product.asp?catid=48&prodid=265