www.extech.com

ellis76016, 2003-05-26

Introduction

I wonder if the Extech 382860 is an OEM of Metex's "3 3/4 digits Multi display digital multimeter M-3860M"?
See: http://www.metex.co.kr/viewproduct_3_e.html

Since I couldn't find anything on the web about this meter other than the same manufacturer's information so I thought I'd show a (very) quick look at the power meter functionality.

The reason we purchased the power meter was to examine exact power consumed by the computers and peripherals at our school. So to demonstrate that function I decided to measure the power consumption of my home computer and collect the readings on another computer. You don't have to use the software to have the meter take power readings.

The kit came with the meter, 3-prong socket/plug power adaptor, DB25 female RS-232 interface to meter cable, data logging software, type K temperature probe, test leads, 9V battery and carrying case.

I am not an electrician and you need to follow all your local codes and safety precautions for your equipment.

The setup is fairly simple and I used default setting in almost all instances. First I installed the "Multiview" software on a 1Ghz P3 running Windows XP Professional. I then connected the serial cable to the meter and the other to the P3's serial port. I then connected the power adaptor to the meter. See meter.jpg

I unplugged my P4 computer from the wall socket. I then plugged the P4 computer into the power adapter. I then plugged the power adapter into a 3 conductor extension cord and finally plugged the extension cord into the wall. See unplugged.jpg and plugged.jpg.

I turned the meter's main switch to "Power" and turned on the meter. The meter immediately began to read between 4W and 5W. I assume this it the power needed to turn on the 5VDC need for the main power switch. I then turned on the P4. The reading jumped up to +120W as shown in face.jpg. Once the P4 had finished booting the power settled down to a steady 90W. I then shut down my P4.

I then started the MultiView software on my P3. When I clicked the "Online" button the software would give me some kind of "communications error". It was a simple matter to setup the software to COM2 and then the meter went online. The once online the software mimics the meter face and selection dial. See online.jpg.

To view a graph of the data you must use the "Acquire" button. A "Control" window will pop up. If you want save the data you must first select the "Save" check box and the program will then prompt you for a file name. Click "OK" and the "Acquire" windows opens. See control.jpg.

Once the "Acquire" windows came up I restarted my P4.

In the "Acquire" mode you will get three sub-windows. The "DMM" window shows. The "WIN1" shows . I had to do into the Menu and set the parameters on this by default it was set to 1000W per division and the windows was on it's small setting. I reset them to the larger windows and 25W per division. The "Status" windows shows some of the thing that were set the previous "Control" settings. When you're done just exit via the "Menu". See dmm.jpg, win1.jpg, and status.jpg.

Once I had the display set I ran my P4 thru a series of tests. I let the PC finish booting and it settled down to about 92W. I ran a popular 3D video benchmark program. This amazed me more than anything else. The power reading jumped to around 130W with a peak reading of 148W. I then let the PC settle back down to a steady idle of 92W. I then had Windows XP shut down the PC into "Stand By" mode. Which measured in at about 78W. I was not impressed. I wanted to see how power the hard disk took so I woke the system up and began a defrag. The power consumption only jumped by about ~4W to ~96W. I guess this is why you can parasitically power a standard IDE drive in an external box via a USB or Firewire cable. I then shut the PC down. Total elapsed time 14.5 minutes.

To view the data just use the "Playback" button. The playback portion will ask you which file you want to playback and will then pop up the "Playback" window with two sub-windows. The "Main" windows shows you the data that you have recorded and it allows you to move a cursor that will displays measurements for that point in time. The "Status" windows is self explanatory. See main1.jpg, main2.jpg and statusplayback.jpg.

After the tests I imported the data file, "data02.txt" into a Microsoft Excel spreadsheet and charted out the entire test. I've posted all these files at:

data file at: ellis76016\extech382860\data02.txt
the data and a graph in Microsoft Excel 2002 at: Chart at : ellis76016\extech382860\data02.xls
a jpg version of the Excel Chart at: ellis76016\extech382860\chart.jpg

If you have any questions or comments about this page please email me at: ellis76016_replacethis_comcast.net with at sign.