A blog on the repair, operation and calibration of surface analysis systems and components including electron spectrometers, sputter ion guns and vacuum related hardware. Click on the Index tab below to see a list of all posts. Visit our website at http://www.rbdinstruments.com
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.
If you run multiple USB devices that operate as virtual RS232 COM ports (the ubiquitous serial port standard) on Windows, you may have run into problems with conflicts between devices. An application may connect to the appropriate device when it’s the only one connected, only to “get confused” if there is another device sharing the PC. Happily, there are a few simple things you can try that will often resolve the problem.
9103s and Arduinos Playing Nice Together
A 9103 Picoammeter and Arduino
To most Windows applications, virtual COM ports (VCPs) all look the same. An application can open a port and and attempt to communicate with the connected device, but since there’s no fixed protocol – each device speaks its own “language”, any message sent can have undetermined effects if the device you’re communicating with is not the one your were expecting. Some applications simply connect to the first COM port available, other’s may provide a way to select the COM port your device is connected to – but you’re still responsible for figuring that out.
When manufacturers produce hardware for PCs they can apply for unique vendor ad product IDs for their device, and there are ways for applications to safely query these. But that only solves part of the problem. Many devices use third-party USB chips and drivers from companies like FTDI, so they share the same IDs. These devices look the same to a Windows client application, or to a person perusing the Device Manager in Control Panel.
RBD’s own 9103 Picoammeter utilizes FTDI’s popular USB VCP chips, as do many versions of the popular Arduino microcontroller boards, so these two sets of devices can be confused by client applications when used on the same PC. And s it turns out, they are often used together. Here are a few tricks for getting these device to play nice together.
Solution 1: Connect Each Device and Run Each Client in Order
Many applications require you to specify the port for the selected device. Others (like Actuel for the 9103) poll the COM ports in numerical order and check and connect to the first available. If these devices first check the vendor and product ID (like the 9103), they will at least skip ports that do not match. But they cannot distinguish between two devices using the same USB chip (like FTDI’s). Setting up a device connection / application order can solve this.
In the case of a 9103 / Arduino conflict, remove all other devices, then plug in the 9103 and power it on. Next run the Actuel software. The software will find and take control of the 9103 port, and once assigned, you can safely plug in the next device and run its client.
Another order might make more sense for your particular application. Experiment with your configuration, and there are more than two devices, try getting two working first. Document the process and just make sure it’s followed anytime you reboot / power-on.
Solution 2: Change the COM Port Number for a Particular USB Port
You can force Windows to use a different COM port number than the one automatically assigned. This may help with applications that select the lowest numbered port.
For example, if the 9103 is connected to COM4 and another FTDI device is on COM3, the 9103 client software may incorrectly select the device on COM3. Setting the 9103 to COM2 may allow you to now connect the devices and run the client applications in any order, depending on how those other devices / applications behave. Some experimentation may be necessary.
With the 9103 connected and turned on, run Control Panel / Device Manager, and find the selection for “Ports (COM and LPT)”, click and you should see an entry for “USB Serial Port (COM4)” (the COM# may be different of course). Double-click for properties.
The COM port settings for the 9103
Now select the “Port Settings” tab, and click the “Advanced…” button. From this window you can select a new COM port assignment:
Choosing a COM port for the 9103
Keep in mind that plugging a device into different USB port will change the COM port assigned to it.
More Info
Of course, you’ll want to ensure you have the latest drivers installed. For FTDI, they can be found here:
If you’re thinking of programming your own serial port application, here’s a quick tutorial at the API level. Many popular languages include code for VCP programming, and third-party libraries are available:
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.
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:
