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DL24 Active DC Load Windows PC application

NEW Updated November 15, 2022 The DL24 - an Affordable Active DC Load. The DL24 is an inexpensive adjustable DC power load (up to 150 Watts/30 Amps) with a voltage range of 2-200 VDC. It comes as a "bare board" and is of Chinese design and manufacture. It has a limited feature set that can be enhanced for more professional or advanced hobiest use by employing a more complete PC application with features described here.

Slightlty Older Updated June 6, 2020 = modified to add Continuity function, January 8, 2023 The Vici VC8145 Digital Multimeter is a comparatively inexpensive benchtop instrument that offers good performance and accuracy. It is not a direct competitor to other more expensive Chinese manufactured meters, such as are sold by Siglent or Rigol. However, the VC8145 is much lower cost point and it offers 80000 count resolution - with some ideosyncracies that are well documented elsewhere. I am not going to review the instrument here.

One feature that makes this instrument useful, beyond simple benchtop use, is the RS232 interface that allows data viewing logging from a connected computer. The RS232 interface is optically isolated internally. This isolation is a safety feature that is a "must-have" for anything more than casual use. Modern computers often do not have built-in RS232 serial ports, so one must use a USB to RS232 adapter. The power to supply the optical isolation circuitry is derived from the RS232 serial port's DTR and RTS control lines. Not all USB adapters are designed to provide true RS232 singal output levels, so you may need to try several different ones to find one that works! The one that I use for this purpose was manufactured by Sewel. Two othe adapters that I tried were not compatible.

When you find a serial adapter that is compatible, you still face a significant challenge. The VC8145 multimeter is delivered with a completely unusable PC software application. It works, marginallty, under Window XP only (who uses that?) and is prone to crash unexpectedly.

I wrote a "work in progress" application to help with this situation. I wrote it using Microsoft Visual Studio Community™ Edition software (free download from Microsoft). I wrote the application using Visual Basic .NET. Readers of my book, Visual Basic Programmer's Guide to Serial Communication 5, will find the source code for this application on the CDROM download that may be purchased from me (details here). The source code license is virtually unrestricted, giving others free reign to modify it to meet their personal needs.

The application is designed for Windows 10 and 11. You may download it using the link here. Unzip and run Setup.exe.

Contact me with issues or suggestions.

The software automatically identifies a serially connected VC1845 meter. The functions implemented include:

- A simulation of the VC8145 front panel.

- Two "hotspots" are defined. These are the "Range" and "Select" buttons.
Clicking on these buttons in the UI transmits the appropriate command to the meter which should perform
the equivalent operation that would have been achieved using the actual meter buttons.

- Other "hotspots" are defined in the UI, but are not implemented in the software.
The source code provides the foundation for expansion beyond basic functions.
These additions will be limited to the API provided by the manufacturer (which, unfortunately) is not complete.

- A menu is provided to switch the Software Display mode between "Digital" and "Graph".
"Digital" is similar to the meter LCD. "Graph" displays a strip-chart of that shows the main display value.

- Another menu sets the polling interval (update rate for the displays and for logging).
Intervals between 100 mS and 60000 mS (1 minute) are supported.

- Data logging to a Comma Separated Value (CSV) file may be done using the Logging menu.