4
\$\begingroup\$

I was asked to bought some equipment to measure the current consumption for the IoT devices. The company is a startup and has a limited budget for this (let's say less than 5k$).

I'm looking for an instrument that can:

  • Capture the sleep current (around a few uA)
  • Capture the active current (around a few mA)
  • Capture the transmiting current (around a few hundred mA)
  • Can store the recorded samples in file (about 100 millions samples or more). Testing time can last for 1-2 days to estimate the battery life.
  • Sample rate >= 1 KSamples/s

Would you please suggest me some names (DMM or oscilloscope)? Do I need a current probe for this purpose?

Improve this question
\$\endgroup\$
  • 1
    \$\begingroup\$ Rigol DS1000Z has a promotion with 24Ms memory but not 100Ms, but you have to program the scale changes in time and then dump intervals of captures \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 8 '18 at 5:34
  • 1
    \$\begingroup\$ Thank you @TonyStewart.EEsince'75 for your suggestions. I found 34465A DMM from Keysight Techonology to be fit with the requirements. Before suggesting this to my manager, may I ask if (1) you have any oscilloscope suggestion (DS1000Z could not store data into USB. Since we want to estimate the current consumption for 1-2 days. Internal memory won't be sufficient); (2) for oscilloscope, I need to use a current probe or a shunt resistor, do I? (3) I feel like 34465A is one of the cheepest for the same specs. Am I correct (well, I would like the cheapest one)? \$\endgroup\$ – Tam Ho Huu Minh Mar 9 '18 at 0:02
  • 1
    \$\begingroup\$ Better to talk to local Reps and get demo units \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 9 '18 at 1:59
  • 1
    \$\begingroup\$ DC current probes are expensive. 50mV shunt is cheap use Keithley \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 9 '18 at 2:12
  • 1
    \$\begingroup\$ saelig.com/MFR00062/PSBE100015.htm \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 9 '18 at 2:38
1
\$\begingroup\$

I think a keithley SMU or an equivalent would be your best bet. It is within your budget and does exactly what you need.

https://www.tek.com/keithley-source-measure-units/keithley-smu-2400-series-sourcemeter

there is also a battery simulator, but I think it lacks some of the features you need.

Improve this answer
\$\endgroup\$
0
\$\begingroup\$

Not a complete answer but a few pointers:

  • Nordic Power Profiler kit: https://www.nordicsemi.com/Software-and-Tools/Development-Kits/Power-Profiler-Kit Works great with Nordic dev boards, easily usable for any other microamps to milliamps range circuit. Specs are 77kHz, 0.2uA resolution. Can record the millisecond long high current spikes when the nRF51 radio is on.

  • EEVBlog uCurrent: http://www.eevblog.com/projects/ucurrent Solves the problem of voltage drop through a sense resistor quite nicely. Good analog bandwidth at 300kHz (better than Nordic), converts uA/nA current to mV voltage (so can measure much lower current than Nordic), but you still need a DSO or fast data logger to record the output. uCurrent+Saleae Logic is a good combo for very long recordings (really, just limited by your hard drive/SSD). Hours to days at 100ksps works.

I've used both of the above for fairly complex projects. Never had access to the big rigs (Keysight, HP etc) so I can't compare. All of the above together is well under $1k.

Improve this answer
\$\endgroup\$
0
\$\begingroup\$

Disclaimer : I am the designer for ZS-2102-A.

A power profiler is most suited for this application. There is one from qoitech which retails on Digikey and other distributors.

Another good one is "ZS-2102-A" from ZSCircuits. It is available for sale at www.anglercircuits.com. This tool can measure from few uA to 1A with 2us response time. It can record practically unlimited record time. Available for $699 with added discounts and free shipping.

Improve this answer
\$\endgroup\$
  • \$\begingroup\$ Do you have an affiliation with anglercircuits? \$\endgroup\$ – Voltage Spike♦ Apr 13 '19 at 22:03
  • \$\begingroup\$ Disclaimer : I am the designer for the ZS-2102-A and own the company ZSCircuits \$\endgroup\$ – IOT Mapper Jun 7 '19 at 10:11
  • \$\begingroup\$ You need to, at least, add that to your user profile and should state it in your post (as you have done). Otherwise your posts will be deleted as spam. If you do it in your profile you can add a link there. \$\endgroup\$ – Transistor Jul 24 '19 at 10:02

Not the answer you're looking for? Browse other questions tagged or ask your own question.