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.

9103 Actuel Beta: Data Cursor and Auto-save

UPDATE: A new Actuel Beta featuring a data cursor and auto-save is now available.

Actuel, RBD’s Windows application for controlling the 9103 USB Picoammeter, has currently been updated with some great new features. While the official release is a few weeks away, the beta release contains some new features in addition to the previously previewed micro-window display.

Auto-Save while recording:

In response to customer requests, we’ve added a feature to automatically save data while recording. The auto-save feature comes in handy when leaving the 9103 unattended for long periods. While rare, brownouts, etc., can cause a temporary communication failure between the 9103 and PC, and USB failures can sometimes lock-up or crash a system. Auto-save ensures that data is stored to a text file every 5 minutes, and again when recording is stopped (for completeness).

Auto-save always works automatically when multiple 9103 picoammeters are synced together. Simply select the option for all instances of Actuel, then select the file name (and keep the Data window open for each instance you want to record/save from). The data from each 9103 will be appended to the file sequentially, separated by the device identifier.

9103 Actuel Auto-save Feature

Data Cursor:

Sometimes it’s handy to see the exact data at a particular point in time during or after data acquisition. While high sampling rates make it difficult to mouse-over every data point in large data sets, the data cursor can help track current vs. time more easily without the need to export data as text. By simply hovering over the graph, a vertical line appears, while current and time is displayed in the upper right-hand corner of the graph window.


As always, Actuel is free for all owners of a 9103 Picoammeter. Meanwhile, you can download the most recent version of Actuel here:

Download Actuel for the 9103 USB Picoammeter

More Information on the 9103 USB Picoammeter

Programming the 9103 Picoammeter

Programming the 9103 Picoammeter

Progamming the 9103 Picoammeter

RBD’s 9103 USB PIcoammeter is packaged with Windows application software for control, current display, data-logging, and graphing. However, it’s often desirable to use the 9103 with other operating systems, integrate it with other hardware or software systems, and/or extend the capabilities of the application software. Fortunately, the 9103 utilizes an ASCII command set that exposes all of its features. Programming the 9103 Picoammeter is straightforward and easy to test.

A complete guide to programming the 9103 picoammeter can be viewed and downloaded  from RBD’s website here. This post will give you an overview of setting up communications with the 9103 and the message structure for controlling the unit and gathering status and data.

Of course, every programming environment is different. As long as you are working with a tool that supports USB communication and text streaming, you can create a custom application for your 9103.

Setting up Communications

If you are using your 9103 with Windows, the installed driver creates a virtual serial COM port. RBD’s Actuel application software uses this port for communicating with the 9103, and any application you use to interface with the 9103 will use this same port for communications.

For other operating systems, you’ll need to download the appropriate driver from the manufacturer of the USB communications components, FTDI. Those drivers can be found here.

If you are interfacing the 9103 with LabView, drivers and scripts can be found on the 9103 downloads page.

Communications Protocol

The communications protocol for the 9103 is typical for many serial devices. Whether you configure the USB port using your operating system or program it within your application, the protocol is as follows:



Bits per Second (Baud Rate)


Data Bits




Stop Bits


Flow Control


Sending and Receiving Commands

Communication with the 9103 is asynchronous. Most commands sent from the computer control device to the Picoammeter will be answered with a response, which may include an error message if there is a problem understanding/executing the command.

All messages are delivered as ASCII text – there is no binary message data. This includes the actual data delivered by the 9103, which is a formatted ASCII value.

Depending on your programming environment and application, you’ll normally be coding (at the least) logic to deliver the messages to the 9103, as well as to monitor the USB port and parse incoming messages.

Message Formats and Sample Messages

All messages are preceded by the “&” character, followed by a single character denoting the command or data type, as well as additional characters representing command parameters or data.

Here are a few examples:

I – From PC, command message to set the data sample interval, parameter is in milliseconds, 0015 to 9999.Example: ‘&I0500‘ sets the sampling interval to 500 milliseconds
F – From PC, controls the filter settings for the sample data. Allowed values are 000, 002, 004, 008, 016, 032, and 064.Example: ‘&F016‘ sets the filter value to 16

Data and status are passed back to the PC from the 9103 using a similar format. For example:

E – From device, sent if there was an error. Includes string description of error.

A full description of the command and data messages, as well as additional information on programming the 9103 Picoammeter are found in the 9103 User Guide.


Using Actuel’s Console Window For Debugging

If you are communicating with the 9103 using Windows, you can view the communications taking place in real-time using the Console window – simply click the Console button on the main window. You can also type commands here and see the results in real-time.