EEZ Bench Box 3

by Envox

Modular, open-source test & measurement chassis

View all updates Jul 01, 2021

Latest Firmware *1.7* Released and a Note for Two-Channel BB3 users

by Denis Kotlar (a.k.a. prasimix)

We are pleased to announce that BB3 firmware version 1.7 has been released. As before, you can find instructions for the firmware upgrade in Chapter 13 of the user manual.

In this version, 42 published issues (fixes and improvements) have been resolved, thanks in large part to your feedback and suggestions. We would highlight the following features:

  • Simple function generator that can be activated on power modules (DCP and DCM) as well as on SMX and MIO. One of the interesting options is the ability to generate half- and fully-rectified waveforms on a DCP module. This can be used to simulate rectified AC mains for testing the final stage of a power supply, battery charger, etc. Set voltage to go up to 80 V and current up to 10 A if two coupled DCP modules are used.

    Function generator screen

  • Modified Data logger (DLOG) that now accepts more than four signals, sampling speeds over 1 KSPS and operation with mixed signals (analog and digital). Furthermore, it is now possible to insert bookmarks (via PC or UART port on the front panel) using SCPI commands during data logging.

    Dlog screen

  • UART support: it is now possible to communicate with BB3 via the DIN1/DOUT1 pins on the front panel. Three modes are supported: Buffer, SCPI, and Bookmark. In SCPI mode, it is possible for an external device (another BB3 or D.U.T.) to directly control the BB3 using supported SCPI commands.

  • Pinout page: the module info page now contains a Pinout page showing the module terminals as well as all resource numbers. This can simplify SCPI programming.

    Pinout page

  • Updated versions of the English User Manual and the SCPI reference guide are also now available and include changes introduced by firmware v1.7.

Unfortunately the German version of the User Manual is not yet synchronized with this firmware version because we no longer have a person available to do so (If anyone is interested, please feel free to contact us).

Note to owners of the two-channel BB3 kit

Finally, one note to owners of the two-channel BB3 kit, i.e., all those who have two Mean Well LRS-150F-48s to power DCP or DCM modules. It turns out when the two Mean Well’s are turned on, they put extra stress on the circuit that controls their AC power input. The end result can be overheating of the R4 power resistor (only the AUX-PS module r3B3, green PCB is affected!). As a remedy for this, it proved sufficient to install an X2 capacitor in parallel to the AC input of one of the Mean Wells. The value does not seem to be critical, as the problem is solved using a 0.47 uF cap as well as a 4.7 uF we tried.

This problem has been reported and explained on GitHub as #108.

About the Author

Denis Kotlar (a.k.a. prasimix)


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Support EEZ Studio Development

EEZ Studio is a cross-platform free and open source BB3 development environment but also attractive SCPI controller that is used to access many T&M devices using SCPI commands. Its development and support cost us money and your donation will help us to keep it alive and kicking.


BB3 - Starter (Without Peripheral Modules)

A BB3 enclosure kit without bare PCBs but with fully-assembled core modules (AUX-PS, MCU STM32F7, and BP3C DIB 3-slot backplane). The Starter provides an environment for experimenters who are willing to build their own modules or who want a specific BB3 configuration (such as a six-channel BB3).


BB3 - Two Channel (Full)

A BB3 starter kit and two full-featured DCP405 single-channel (40 V, 5 A) peripheral power modules, including an AC/DC power module for each. A two-channel programmable power source with advanced features: remote sensing, remote programming, a down-programmer, and additional OVP (with crowbar).


BB3 - Four Channel (Full)

A BB3 starter kit, two full-featured DCP405 single-channel (40 V, 5 A) peripheral power modules, and one dual-channel DCM220 peripheral power module. Includes all three necessary AC/DC modules. This is the two-channel full kit, expanded to include two additional programmable power sources.


DCP405 One Channel Module (Full)

A full-featured DCP405 single-channel (40 V, 5 A) peripheral power module with remote sensing, remote programming, a down-programmer and crowbar OVP. Includes an AC/DC module.


DCM220 Two Channel Module

A DCM220 dual-channel (2 x 20 V, 4 A) peripheral power module and its AC/DC module.


Cable Set

Two pairs of high quality, silicone, color marked (black-red), 1 m connecting cables; a pair of clip-on probes; and a pair of insulated crocodile clips.


BB3 Enclosure & Bare Boards

A BB3 enclosure kit with a wire harness, nuts and bolts for the three core modules, a 4.3" TFT touchscreen display, an encoder knob, and an 80 mm fan. Includes a set of bare PCBs for building the three core modules (AUX-PS, MCU STM32F7, and BP3C DIB 3-slot backplane) as well as PCBs for building one DCM220 two-channel peripheral power module and two single-channel peripheral power modules (either the DCP405 or the DCP405B, as they can be assembled using the same PCB). Suitable for builders with the necessary skill, time, and patience.



Envox d.o.o. is home of the Envox Experimental Zone (EEZ), an open source initiative to bridge the gap between DIY / hobbyist / educational / low-budget and professional / commercial test and measurement solutions.

Denis Kotlar (a.k.a. prasimix)

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