• RE: Simultaneous voltage and current acquisition

    Yes, that's exactly what I want to do: "Measure the current and voltage of my films as a function of mechanical stress". To do this, I need a measuring device that can do this, because when I use two devices, I can only force one of the instruments to Zero and measure with the other instrument. Since I want to characterize my films in voltage and current in a single experiment without using electrical components such as resistors, I don't want to lose any energy, since the next step would be to add an energy storage circuit.
    Maximum voltage is 150 volts.
    If there's no measuring instrument that allows me to measure current and voltage using the same connection points, do you think there's a way of using probes that will allow me to measure voltage at a distance, i.e. without connection to the film?
  • Simultaneous voltage and current acquisition

    Hello, I'm looking for a DMM that will allow me to measure voltage and current at the same time for pvdf samples (which generate charges when pressure is applied). Note that the voltage I get may be high, but the current is very low in the nanometer or microampere range. My aim is to characterize pvdf films and display the current and voltage curves generated by the films on labview.  Thanks for your help and suggestions.
  • Need Help with Piezoelectric Material Characterization Project and Data Acquisition Is


    I am currently a student working on a project involving the characterization of piezoelectric materials. My goal is to simultaneously acquire both voltage and current data from piezoelectric films. To achieve this, I am using a machine that applies mechanical deformation to my piezoelectric films at a frequency of 5 Hz. When this stress is applied, the films generate a certain voltage, which I acquire using a DAC acquisition device, along with a current, which I measure using a KEITHLEY 6485 picoammeter. I aim to visualize this data using LabVIEW.

    However, I am facing two major challenges in executing this project.

    1. **Electronic Circuit for Current and Voltage Measurement:** I am seeking to design an electronic circuit that allows me to measure current in a closed circuit and voltage in an open circuit, while adhering to the specifications of the KEITHLEY 6485 picoammeter. I am wondering about the best practices to follow in designing this circuit while respecting measurement standards and device limitations.

    2. **Incorrect Current Measurements:** When I attempted to measure the current using the picoammeter, connecting it to LabVIEW via GPIB and the RG50 probe, I obtained excessively high current values. These measurements do not align at all with the data specified in the datasheet of the piezoelectric material (PVDF) I am studying. This is concerning to me as I do not understand why these values are so far from expectations.

    I want to emphasize that I am relatively new to electronics, and these issues seem complex to resolve. Time is of the essence as I have less than a month to complete this project. I am therefore seeking your expertise to help overcome these obstacles. Any guidance, technical explanations, or practical advice you can provide would be greatly appreciated.

    I sincerely thank you for your attention to my situation and for any assistance you can offer. Your contribution will be crucial to the success of my project.

    Best regards,
  • RE: Real-time data acquisition: how to achieve high speed with Labview and the KEITHLEY 6485?

    Thank you for your proposal but the DMM6500 will be too expensive for me. However, with the KEITHLEY 6485 I manage to have usable results with a sample that gives high current peaks. But when it comes to the samples where the current is very high, I notice that there is too much noise and I cannot distinguish certain current peaks with the noisy signals. Do you think there is a way to filter the noise without slowing down the acquisition ?<br> You will see some signals when I take my empty measurements in the attachment.
  • RE: Real-time data acquisition: how to achieve high speed with Labview and the KEITHLEY 6485?

    Hello Molina,<br> <br> In fact for my application I need to go much lower than 95 ms between two measurements because I can't get all my desired current peaks. I need at least 10 ms between two measurements. Since I apply constraints every 333 ms on my sample to have current peaks in order to be able to store energy. Since I cannot synchronize the test bench and the abview, the ideal would be to have the time between two measurements in 1ms to be sure that I can measure all my peaks with precision.<br> <br> <br> Do you think this is impossible with the KEITHLEY 6485 pico-ammeter?
  • RE: Real-time data acquisition: how to achieve high speed with Labview and the KEITHLEY 6485?

    <p>Hello Molina,&#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; &#160; thank you for your help. However, the time between two measurements is enormous compared to my application despite my attempts to speed up the execution rate of the pico-ammeter by changing the NPLC to 0.01. Currently, I only retrieve two measurements every second.</p> <p>As a reminder, in the context of my application, I need to measure the current of piezoelectric films when they are subjected to compressions at a frequency of 7 Hz. Indeed, the time between two measurements is very important compared to my needs (I need to retrieve 100 measurements every second at least) and display them in real-time on LabView.</p> <p>However, I have an attached program that allows me to retrieve the 100 measurements every second and display them in real-time on LabVIEW. Unfortunately, these measurements do not seem correct to me, as the first measurement I retrieve is on the order of hundreds of microamps in a vacuum, while the subsequent measurements are on the order of tens of nanoamps.&#160;So from my application I will recover only some nano ampere.</p> <p>Therefore, I am looking for help in solving this problem. Any suggestions would be greatly appreciated. Thank you in advance for your help.</p>
  • Real-time data acquisition: how to achieve high speed with Labview and the KEITHLEY 6485?

    <p>Hello,</p> <p>I currently need help to perform a real-time acquisition of very low current data at a high speed of 100 measurements per second using Labview software and a KEITHLEY 6485 picoammeter with a GPIB.</p> <p>Currently, I use a method that allows me to read 100 measurements in one second and display them on Labview, but my goal is to display these measurements in real-time on Labview. I have included a copy of my VI for reference.</p> <p>I am looking for solutions or advice to achieve this goal. Any help would be greatly appreciated.</p> <p>Thank you in advance for your help.&quot;</p>