This is wrong!!!! It seems to be a null and is very touchy. The one I modified was over 100mA!Earlier I mentioned that the pot nearest the clamp head was an offset trim. Sitting in a chair with the two meters side by side then rotating 360 degrees, one meter (virgin) held the DC current in less than 20mA. Once again degauss took care of it, but then I noticed that the non-zeroed numbers between the two meters was way off depending how I positioned the two meters.
Oh, one more myth to dispel, the ground/guard lead that goes into the fixed jaw, solder point ‘A1’ is for NCV. Pictures will arrive when I have time to take them and have looked into the op amp channels and associated gain on all 4. If not, then it is solely up to the OPA4330 and the circuit design that is the bandwidth limitation, yes? I’m looking for similar/equivalent parts that are still in production to see if I can get more details specs such as identifying if they have particular qualities that would limit bandwidth. Digikey shows 2 parts that are physically close match with similar “resting” resistances of ~260 ohms, the HW105A and the HW108A, with the 105 being the one that matches physical and electrical checks. I digress though, as AMR/magnetoresistive sensors are Wheatstone-based sensors. The EEPROMs are stock atm and so are the meters, but hacking in SMA connectors on each and upping their bandwidth is the intent.
I have 2 UT210E’s, one being donated to this hacking, both with the DTM0660 controllers. Using a ziplock, boiling water, and some ice-cold cold packs, I opened up the jaw to see what was what since Joe Smith doesn’t want to share his high bandwidth hack. There are 2, 4-pin, ~1.3 mm x 2.1 mm x 0.55 mm SMDs under the nubs in the fixed jaw with the package marking of ‘D’. Don’t know if I’ll have time to verify this post today regarding the resistors for the op amp, because in order to do so, I would like to verify the sensors used for the meter.Įveryone is assuming that Hall Effect sensor(s) are in play, but my initial findings so that AMR/magnetoresistive sensors are actually employed.
MIN/MAX and RS232 is the only major functions I really miss in this little clamps. No luck Looks like it’s not supported by the firmware as well as RS232 data output (pin 22). I’ve tried to hack MIN/MAX button by connecting pins 26 and 23, witch are used for this function in the other DTM0660L DMMs. UT210E chipset itself does have support for MIN/MAX.Hycom DMM Chip (Markings: Hycom H203 DTM0660L R3MR81A).I attempted to run a sweep from 100Hz to 300KHz. Test 5 using the loop, the clamp was connected to the network analyzer.You only have the 2XAA batteries as a source and these parts will run down to 1.8 volts. The INA333 may be another one to look at. If you wanted to buffer the signal to drive your scope it seems parts are pretty limited.The AC/DC and offset buttons do not have any effect on this signal. You will note that as you change the range the amplitude on at R7 will change. If you then probe pin 14, you will see the current signal. If you probe the positive and negative supply pins of the chopper, you will note they are above and below our reference. Looking at the circuit, you will see an 8-pin quad op-amp (U4).TI OPA4330 quad opamp (Markings: TI O4330A 44K G4 AN50).battery life: 200 h current consumption:.