OT: My birthday present, a WT310E.

Is it AC or DC coupled?

I ~think~ they are DC coupled ?. They use a shunt. We use them for AC.

Hopefully Win got the communications options ? For measuring efficiency... Unless this one has multiple channels.

That yokogawa link states "Bandwidth DC, 0.1 Hz to 100 kHz"

No, it's single-channel, with the standard RS-232 interface. For any serious job it'd take the hard- to-get AC measurements and would be used with one of my dual-channel SMUs, that can take better than 0.1% measurements on the DC portions. Good for AC offline supply circuits, PFC stages, inverters, etc., areas I've avoided, because, how to measure?

Here's the WT300 series datasheet.

I had to use Google to find it, because Yokogawa's web pages don't seem to admit to the WT310's existence.

OK, I found it. Here's the WT310E datasheet, where they say E means enhanced, introduced in 2015. (Another spot said E means economy. Haha, I wonder which is correct.)

What does that mean?

It means the answer to your question appears to be "yes".

That's confirmed by Win's second PDF which states "The WT300E series cover broad ranges of current input from a few mA up to 40 A rms. It can measure waveforms which include both AC and DC. Users can use it from the low currents of standby power to the high currents of induction cooking."

and

"The WT300E series can measure all DC and AC parameters. It can also measure harmonics and perform integration simultaneously without changing the measurement mode. The WTViewerFreePlus software is used to monitor and save all measurement items of up to 200 parameters."

with a crest factor of 3 or 6 or 6A. I don't know what "6A" might mean.

Can you draw the frequency response graph for me?

LF is either DC or 0.1Hz (ac), the HF end is 100 kHz. (at least that's how I read it.)

George H.

Since it can do RMS calcs at 100kHz, I suppose its sampling rate is somewhat higher than that.

Power and RMS measurement is statistical, so the Nyquist Rate/Sampling Theorem is not applicable. I did a lot (a LOT) of 60 Hz power measurements sampling at around 27 Hz, a magic rate that did not alias with significant harmonics of 60 Hz.

RTFDS, as provided by Win.

There are graphs of error vs frequency there.

The "E" version of the datasheet makes clear it's enhanced, with improved specs and new features. Anybody know WT310E list price? I paid $2250.

Good enough. If you ever decide to get another one, you can control them to capture at the same time for simultaneous measurements like efficiency.

It confused me at first too... It's probably...

I think

Probably so, badly worded.

Yokogawa's japanese language page has PDF catalog pages, they include list prices. Apparently this is considered a basic necessity in Japan. Other test instrument manufacturers like Sanwa also show their list prices openly on their japanese site, but not on their overseas sites.

This one is for the 300E series, prices are on the last page:

A basic WT310E with nothing else is 187000 JPY, Harmonic measurement option is 5000 JPY, external sensor input (without sensors themselves) is 10000 JPY, Ethernet is 5000 JPY, D-A module with 4 channel analog outputs is 10000 JPY. List prices are pre-tax, so add tax for total.

Assuming yours has harmonic measurement (-G5), no ethernet and nothing else, that would be listed new at 192000 JPY = ca. 1780 USD. With sensor inputs and harmonic measurement: 202000 JPY ~ 1870 USD.

Consumption tax (like a VAT in Japan) is 8% currently (may become 10% in the near future).

From what I've been able to tell, seeking quotes, the sales restrictions for these products is very strong. By the time you purchase from the authorized distributor at your location, the prices have gone up through the roof.