Tag: Rigol DM858

Where is the ADC? RIGOL DM858 Teardown | Voltlog #486

Ever wondered what lies beneath the sleek exterior of the high-tech Rigol DM858 multimeter? In a recent teardown video, we took a deep dive into the inner workings of this precision instrument, uncovering the components that make it tick. Right off the bat, the teardown revealed the beautiful construction and assembly quality, with key areas like power supplies, connectivity, and a clever system-on-module design.

The power supply section was straightforward, with a USB-C input and a series of switchers to step down the voltage to the required levels. The real star of the show was the SODIMM module, housing an Allwinner A40i-H quad-core Cortex-A7 processor, RAM chips, flash memory, and a power management circuit.

This modular design offers several advantages, including cost savings, flexibility, and the ability to swap out components as needed. Moving on to the input section, we encountered a curious square PCB module housing the user-accessible fuse and input protection components like gas discharge tubes, Metal Oxide Varistors, and clamping devices.

Underneath a small shield, we found relays likely responsible for input switching and range selection. One of the most intriguing discoveries was the potential use of the microcontroller’s built-in ADC (Analog-to-Digital Converter) instead of a dedicated ADC chip. This design choice, if true, would be a clever solution for high sampling rates and accurate measurements.

However, not all mysteries were solved. We encountered a few unidentified components, leaving us scratching our heads. Can you help shed light on these enigmatic parts? Leave a comment below and join the discussion!

RIGOL DM858 Multimeter Review | Voltlog #485

The Rigol DM858 is a high-quality multimeter from a reputable manufacturer, boasting a 7-inch touchscreen display and a sleek form factor reminiscent of their oscilloscope line. With a wide range of measurement capabilities, including 10A current, 10mF capacitance, and 0.03% accuracy on DC voltage, it certainly packs a punch in terms of specifications.

One of the standout features is the web view and control interface, allowing you to access and control the multimeter remotely from any computer or mobile device connected to your local network. This level of convenience is a welcome addition to any modern lab setup. However, the DM858 is not without its flaws.

During testing, a concerning auto-ranging bug was discovered, where the meter fails to detect the need to switch to a higher voltage range, potentially leading to incorrect readings and even internal damage. Rigol has been notified, and a firmware fix is hopefully on the way. Another disappointment is the lack of a built-in data logging feature, which seems counterintuitive for a multimeter in this price range.

While the user manual mentions data logging capabilities, the implementation appears incomplete and unintuitive. Other minor gripes include the inability to use math functions in auto-range mode, the lack of a thermocouple probe or USB cable in the package, and the recommended software being outdated and incompatible with modern Windows versions.

Despite these drawbacks, the DM858 remains a compelling option for those seeking a multimeter with a large touchscreen display and remote control capabilities. Its unique form factor may appeal to those with limited bench space or a preference for monitor-mounted instruments. Priced at around $500 (or €440 in the EU), the DM858 competes with alternatives like the UNI-T UT8805E, which offers better specifications at a lower cost but lacks the touchscreen and web control features.

Ultimately, the decision to purchase the Rigol DM858 will depend on your specific needs and priorities. If the touchscreen, remote control, and unique form factor outweigh the concerns raised in this review, it could be a worthwhile investment for your workbench.