Best alternative to the QTI DirecTemp USB temperature acquisition system

Why QTI is discontinuing the DirecTemp line

QTI Sensing Solutions was acquired by CTS Corporation (NYSE: CTS) in July 2019. CTS is a publicly traded manufacturer focused on mission-critical applications in aerospace, defense, and industrial OEM markets. The DirecTemp USB thermometer line, a general-purpose data acquisition product, does not align with that strategic profile. As QTI rationalizes its portfolio around its core high-reliability markets, DirecTemp is being discontinued: a good product discontinued not because it failed, but because it no longer fits the parent company’s priorities.

What the DirecTemp line offered and what you need to replace

DirecTemp instruments connected directly via USB and auto-installed as a Human Interface Device: no drivers, no IT ticket. A lab technician could go from box to live data in minutes. That immediacy was the core value proposition, and it was backed by real measurement capability: accuracy down to ±0.05°C over a 0 to 70°C range, with a 14-bit analog-to-digital converter that made the platform credible for precision laboratory work, environmental monitoring, and process validation.

The line also offered two communication modes. Plug-and-play HID was used with QTI’s bundled Windows software for visualization, logging, and Excel export. A separate serial (virtual COM port) version allowed developers to integrate temperature acquisition directly into custom or third-party applications, which made DirecTemp a common choice in automated test systems where the sensor needed to talk to a script, not a desktop application.

Calibration was handled in QTI’s own metrology laboratory. NIST-traceable certificates were available, and users could return instruments for recalibration. In regulated environments (life sciences, quality laboratories, food safety) that traceability chain was not optional, and QTI’s in-house service made it straightforward to maintain.

Finally, DirecTemp was available in over ten probe configurations: stainless steel general-purpose probes, ring lug, polyimide tube, NPT housings, and others. The same USB acquisition interface could be deployed in very different physical environments without any change to the software layer.

The more significant difference is scope: the same USB platform also measures relative humidity, atmospheric pressure, CO2, VOC, light spectrum, and particles. If your application evolves and you need to add CO2 monitoring to a cleanroom or humidity logging to an incubator validation, you add an instrument to the same system rather than introducing a second platform.

Calibration traceability is fully supported. ISO/IEC 17025 accredited certificates, traceable to NRC (Canada) and NIST (United States) standards, are available as a separate purchase through Transcat, an SCC-accredited laboratory. Instruments ordered with the -CAL option go further: a 3-point polynomial user calibration mechanism, managed through DracalView, allows you to recalibrate against any reference at any ISO 17025-accredited laboratory worldwide. You are not tied to a single vendor’s recalibration service, which is a meaningful difference in any multi-site or long-lifecycle deployment.

DracalView is free, and all future updates remain free. It supports an unlimited number of instruments simultaneously, with synchronized timestamps and harmonized units across all of them in a single output file. For programmatic access, Dracal publishes four integration paths:

• a REST JSON HTTP API for real-time process control and test automation;
• a MQTT publisher to meet industrial needs and installation;
• a command-line interface (dracal-usb-get) with code examples in Python, C/C++, C#, Java, Node.js, .NET, etc. and LabVIEW;
• and the VCP option for serial integration without any runtime software dependency (guide, code examples and LabVIEW examples).

All tools except the VCP hardware option are free, and all code examples are available on Dracal’s public GitHub.

Next steps to evaluate Dracal as your replacement

The starting point is defining which DirecTemp capabilities you actually rely on. If your workflow is temperature-only, virtually any standard Dracal temperature instrument is a direct replacement, the RTD300 being the closest to the QTI DirecTemp. If you also need humidity, pressure, or CO2, a multi-parameter instrument such as the PTH series covers multiple requirements on the same USB platform without adding complexity. If your existing software communicates via serial protocol, order a model with the VCP option (VCP- prefix). If you work through a REST API, MQTT or command line in a non-OEM project, the standard USB model is sufficient and simpler.

For calibration: add an ISO 17025 certificate at checkout for any compatible instrument. If you perform recalibration internally or through a third-party laboratory, add the -CAL option at the same time. It costs more upfront and saves time and money at every recalibration cycle thereafter.

DracalView is free to download. You can install it and explore the interface before placing any order. Code examples for all integration methods are available on Dracal’s website. But still, do not play “Where is Waldo”. Technical questions are answered by engineers and scientists within one business day at info@dracal.com. Orders can be placed directly on Dracal’s e-commerce store; a cart converts to a formal purchase order request with one click. In-stock items ship within 3 business days.