Tag Archives: current measurement

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

Posted on by
Reply

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

Programming the 9103 Picoammeter

Posted on by
Reply

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:

Setting

Value

Bits per Second (Baud Rate)

57600

Data Bits

8

Parity

None

Stop Bits

1

Flow Control

None

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.

 

 

 

 

Synchronizing and Identifying Multiple 9103 Picoammeters

Posted on by
Reply

four pico ammetersTwo exciting new features are now available for the 9103 Picoammeter: Synchronization and Device Identification. These features transform the 9103 from a single current measurement device to a multi-channel picoammeter. Up to 127 channels!

 

Picoammeter Synchronization

Synchronization is provided by RBD’s free Actuel picoammeter control and display software. Multiple instances of the software now communicate start and stop information for sampling and recording of data. Additional features are also being added to facilitate exporting and combining of data-sets from multiple picoammeters. While the synchronization is not time sample-accurate, this small offset will not be an issue for most applications.

The newest version of RBD’s Actuel software (1.3) is now available. This update includes additional features such as the ability to run in either Windows Admin or User mode.

actuel picoammeter sampleactuel picoammeter graphe

Device Identification

9103 firmware now includes the ability to set a unique string identifier for your 9103 Picoammeter. The ID can be easily changed at any time by the user, and is recalled when the 9103 is powered off/on. This makes it easier to identify 9103 Picoammeters in a multiple-unit environment.

All new 9103’s will include this feature; existing units can be upgraded for a nominal fee and shipping charge.

More information on the 9103 Picoammeter can be found on our website.