High-speed Support Improved in Latest Actuel Release (1.7) for the 9103 Picoammeter

RBD has released Actuel version 1.7 for the 9103 Picoammeter, with improvements for high-speed data acquisition and (especially) data logging and graphing.

The latest version can be found here.

If you do not have a high-speed 9103 Picoammeter and are already running Actuel version 1.6, there no reason to download the latest version. However, high-speed users will find a number of improvements.

Oscilloscope emulation

Although Actuel was not designed to have an oscilloscope emulation (with features such as triggering), at higher speeds you can come close to emulating scope current monitoring.

In the Data Window, click the Show Options button and select “Last” from the Graph Options. You can scroll in increments as low as 0.1 second, but you can type in a smaller increment, such as “0.05” in order to display at higher resolution.

Last time option in Actuel
Using the “Last” time option in Actuel

(Note: The graph display options can get out of sync with data collection if you change and option when recording or after stopping and clearing data – it may be necessary to re-enter the value or reset recording. We’re working to make this smoother in the next version.)

For smoother real-time graphing, use standard-speed at 25 mS unless faster rates are needed

The 9103 can run as fast as 25 mS per sample in standard-speed mode, and 2 mS per sample in high-speed. In order to optimize faster data acquisition in high-speed mode, the 9103 collects 10 samples per message, as opposed to 1.

However, note that if you are collecting data at 25 mS in Standard-speed, your PC will be updated with new data every 25 mS. In High-speed, you’ll be updated every 250 mS.

For that reason, the Acutel software always collects data in standard-speed mode at 25 mS and above, regardless of the high-speed mode settings. It is recommended you do the same if you are writing your own software to control the 9103.

That also means that for real-time graphing, you may not want to sample at a rate of, for example, 24 mS, if you can achieve the same results at 25 mS. At faster rates, the delay in caused by receiving 10 samples per message is less noticeable, but it’s visible at rates of 20 mS- 25 mS if you are graphing only the latest points in relatively high resolution:

Actuel 25 mS Standard Speed

Actuel – 25 mS Standard Speed

Actuel 25 mS High Speed

Actuel – 24 mS High Speed

New high speed 5kV floating Picoammeter

RBD Instruments has released a new version of its 9103 USB Picoammeter which incorporates faster reads per second with 5000 DC volts of isolation to chassis ground.

9103 HV

9103 HV









Increasing the DC voltage isolation from chassis ground to 5000 volts (5kV) opens up new possibilities for researchers such as direct DC current measurement of very small electron and photo multiplier signals.  Electron and ion beam measurements can be biased to reduce secondary electrons or to retard the beam as needed for experiments.

Designed to provide accurate bipolar DC current measurements in noisy environments such as synchrotron beam lines, the 9103 can measure bi-polar DC currents from low picoamps to milliamps.

The drawing below shows how the 9103 is floated on your HV power supply.  The high voltage is referenced to chassis ground, and the signal ground is referenced to the high voltage.   To help keep the supply and signal connections clear, the HV connection is a MHV connector and the signal input is a SHV connector.

Floating picoammeter

Floating picoammeter


There are a number of manufacturers of programmable DC power supplies that can be used to float the 9103 up to whatever voltage is needed (as long as you do not exceed +/- 5 kV).

For example, TDK-Lambda provides a programmable 0 to 6.5kV supply that can be voltage limited to 5 kV and can drive up to 2 mA of current.

The model number for a 120 VAC line input is PHV6.5P2-USB-1P115.  The base model has a ripple of 700mV which is somewhat high, but TDK-Lambda does offer a low ripple option that gets the ripple down to 75mV.  You can also easily make a simple RC filter to do the same thing.    A number of interface options are available (USB, Ethernet, Serial, analog….

TDK Lambda supply

TDK Lambda supply





PHV series

PHV series









The new high speed option for the 9103 increases the reads per second from 40 to over 500, which is fast enough to perform optical chopper experiments.  And, by taking more reads in the same amount of time as the first generation 9103 could, the accuracy is improved.

The Actuel software included with the 9103 provides new features for high speed acquisitions and display, but you can also write your own software to control the 9103 using the simple ASCII commands or in LabVIEW.

Since 9103s can be synced, it is now possible to configure a multichannel DC Picoammeter with up to 256 channels that has high speed, high voltage, or both options.

And if you do not need the high speed or high voltage options, the standard 9103 USB Picoammeter is still available as well.

For more information visit the RBD Instruments website at http://www.rbdinstruments.com


New Feature: Use the 9103 Picoammeter to Automatically Read microCMA Target Current

The latest software releases of Actuel for the 9103 Picoammeter and CMapp for the microCMA now support the ability to automatically read target current when acquiring data.

To use this feature, you must (of course) have a 9103 Picoammeter running RBD’s Actuel software.

Run CMapp for the microCMA, select Hardware Properties from the System menu, and check the option “Use 9103 Picoammeter to read target current.” You only have to do this once.

Turn on the 9103 Picoammeter, run Actuel, and measure your target current as usual. Leave Actuel open. It doesn’t matter whether the 9103 is sampling, but keep in mind that your current settings (sample rate, etc.), will be used.

Now, whenever you take an acquisition (except for an alignment), the target current will be measured at the beginning of the acquisition and displayed with the other electron gun settings when the acquisition is complete.

If you don’t have a 9103, you can still manually enter a value for the target current in the acquisition dialog.

Download the latest release of Actuel for the 9103 Picoammeter here.

Download the latest release of CMapp for the microCMA here.