Test and Measurement Power Supplies

Testing and measurement (T+M) covers a wide range of applications but essentially involves detecting a physical variable (current, voltage, temperature, etc.) under various operating conditions (normal, at the operating limits, or during over-stressed operation) and recording and analyzing the result.

Often, measurement isolation from ground is required because the part being tested or measured may be at a different ground reference voltage from the recording or analyzing equipment. When the T+M equipment is line-powered, an AC/DC converter provides isolation and may be followed by a DC/DC converter to achieve galvanic isolation between separate power rails for inputs of multi-channel or multi-parameter T+M equipment. This prevents cross-talk or interference between signal inputs. DC/DC converters may therefore be necessary even if the measurement unit itself is battery-powered.

Analog input test and measurement sensors commonly require dual-rail supplies to power operational or precision signal amplifiers. The amplified and conditioned output is typically fed into Analog-to-Digital converters, and the data stream is then isolated using Digital Isolators. ADCs and DIs require independent 3.3V or 5V rails derived from the main 12V or 24V supply rail. Finally, digital bus isolators (USB, CAN, GPIB, etc.) are often essential to avoid ground loops, improve safety, or achieve single-fault tolerance in the T+M system.

Line-powered T+M equipment can range from desktop instruments to rack installations, with input voltages varying from 100VAC to 277VAC or higher for some industrial applications. At low power levels (3W to 20W), PCB-mounted parts are often used, such as the RAC03-K, RAC04-K/277, RAC04NE-K/277, RAC05-K/480, RAC10-K/277, RAC15-K/480, RAC20-K, RAC20NE-K/277, and RAC25-K/480. At higher power (40W to 550W), chassis-mounted parts like the RACM60-K, RACM90-K, RACM230-G, RACM550-G, and RACM1200-V are suitable.

Fanless operation is often desirable in T+M environments, and all these models can deliver reliable power at high temperatures without forced air cooling. The 230W, 550W, and 1200W products can also operate with baseplate cooling only. Depending on the model, safety certifications are available for different end-use environments, including IEC/EN 61010, IEC/EN 62368, IEC/EN 60601, and EN 60335. EMC standards are met without additional components, and all parts feature low mains leakage current, which is critical in T+M and medical applications. Additionally, the low output noise of RECOM AC/DC power supplies provides significant benefits for sensitive measurements.

For precise test and measurement systems, the RACPRO1-S series delivers stable output power at 120W, 240W, and 480W. It combines high efficiency, low ripple, and generous power reserves to support dynamic loads. Back-feed protection and certified safety according to IEC/EN/UL 61010 ensure reliable operation in laboratory and test bench environments. The compact DIN-rail format enables easy integration into modular measurement setups.

For Test & Measurement equipment operating in harsh industrial environments such as chemical plants, refineries, or power stations, the RACPRO1-Txx series of high-power-density AC/DC DIN rail power supplies are ideal. They are designed for demanding industrial sensor and measurement applications, offering a 150% power boost for 5 seconds to handle high inrush currents. The input can be 3-phase AC or 450–850VDC. The 240W, 480W, and 960W versions all feature 24VDC or 48VDC outputs, safely distributed to lower-power multi-sensor systems using the RACPRO1-4SP e-fuse module, which individually limits current and protects each output channel.

RECOM offers high isolated DC/DC converters in compact case sizes. The RHV2/RHV3 series provide 20kVDC isolation (12.5kVAC/1 minute) in a SIP16 case for high isolation power supply applications such as hard vacuum ion pumps, X-ray equipment, and high-voltage dust filters.

The REM series offers up to 10kVDC (5kVAC/1 minute) isolation and is certified to withstand continuous 230VAC across the isolation barrier. Output powers range from 1W to 30W. An example application is isolation for temperature measurement thermocouples connected to transformers, transistors, diodes, or capacitors operating at mains voltages. For T+M systems that require functional isolation to prevent ground loops or interference in low-voltage circuits, the RKE series provides excellent value with 3kV, 4kV, or 6kV isolation options.

An isolated data bus transceiver requires isolated power for the serial communication bus, typically provided by an isolated DC/DC converter placed across the isolation barrier and powered from the input supply. Common input and output voltage combinations include 3.3V to 3.3V, 5V to 5V, or 3.3V to 5V.