Marmonix MHT-51 (MHT51) Single-Use Temperature & Humidity Data Logger with LCD

The Marmonix MHT-51 data logger (also written MHT51 or MHT 51) is a one-trip temperature and humidity recorder with its own LCD, so a reading can be checked on the spot without a computer. It covers −30 to +70 °C and 0–100% RH, holds ±0.5 °C between −20 and +40 °C, and out of the box records every 5 minutes for 90 days; both settings can be changed (1 min to 24 h, 7 to 360 days). The screen shows the latest value, the recording and alarm state, and MAX, MIN and AVG for the trip. When the journey ends, its USB end goes into a PC and a PDF report plus a CSV file appear with nothing to install. The IP66 case weighs 16 g and runs on an internal CR2032 cell (part number 7603594). It belongs to the Marmonix temperature and humidity data loggers; the MHT-50 logger is the screenless option for the same job.

MarMonix MHT-51 temperature and humidity data logger Overview

The MarMonix MHT-51  is a premium single-use USB temperature and relative humidity data logger designed for high-integrity environmental monitoring during transit, warehousing, and regulated laboratory workflows. Combining laboratory-grade sensor accuracy with ultimate field usability, the MHT-51 features a high-clarity built-in LCD display alongside an IP66 water- and dust-resistant housing.

Unlike blind loggers, the MHT-51 provides immediate visual confirmation of active recording status, live temperature/humidity values (with 0.1°C / 1% RH resolution), and threshold alarm violations right on the container. Once transit is complete, simply insert the integrated USB connector into any computer to automatically generate secure, tamper-evident PDF and CSV audit reports—with no software installation required.

Key Features & Advantages

What the MHT-51 does for a cold-chain shipment:

• High-Clarity Built-In LCD Screen: Instantly displays live temperature & RH, configurable alarm limits, active logging states, and calculated MAX / MIN / AVG operational statistics.
• Direct USB Auto-Reporting: Automatically compiles and exports standardized PDF and CSV data logs directly upon PC connection—completely driver-free.
• Wide Dynamic Range & Precision: Operating range from -30 °C to +70 °C (-22 °F to +158 °F) with ±0.5 °C accuracy (-20 °C to +40 °C) and 0% to 100% RH with ±3% RH accuracy.
• Triple LED & Screen Visual Diagnostics:
  • Blue LED: Indicates start-delay countdown (default 30 min delay for cargo temperature stabilization).
  • Green LED: Confirms active recording within preset safe thresholds (default: 2°C to 8°C & 20–80% RH).
  • Red LED & Screen Icon: Immediately signals high/low excursion alarm conditions.
• Rugged & Compact (IP66): Encased in an ultra-slim 7.5 mm body (16 g) engineered to withstand harsh condensation and washdowns in refrigerated containers and insulated thermal shippers.

Technical Specifications

Case study: accepting or holding a chilled delivery at the receiving dock

A pallet of medicines labelled 2–8 °C arrives after a long road leg. The receiver has to decide, before signing, whether the goods stayed in range. The EU Good Distribution Practice guidelines (2013/C 343/01) expect the storage conditions on the pack to be kept during transport and any temperature excursion to be reported to the distributor and the recipient.

A screen-equipped single-use logger supports that decision in four steps:

• At dispatch: limits are set to match the label, the button is held for 3 seconds, and the blue LED blinks every 10 seconds until the start delay ends and logging begins.
• In transit: the unit rides inside the load, next to the product, rather than by the door where air swings most.
• On arrival: the dock reads the alarm state and the MAX and MIN values straight off the LCD, then accepts the pallet or sets it aside.
• For the file: recording is stopped, the logger is plugged into a PC, and the PDF goes with the delivery paperwork while the CSV is kept for any investigation.

Two details matter in practice. Plugging the logger into a computer ends the recording, so it should only be connected once the trip is over. And it must stay connected while the report is being written; pulling it out early can leave gaps in the data.

MHT-51 logger: quick answers

Can I read the MHT-51 without a computer?

Yes. The LCD shows the last recorded temperature and humidity, whether it is recording or in alarm, and the MAX, MIN and AVG values, all in 0.1 °C/°F and 1% RH steps.

What happens if the MHT-51 is plugged into a PC during a trip?

The recording stops. USB connection is one of the two ways to end a run (the other is holding the button for 3 seconds), so connect it only when the shipment is complete.

Can the MHT-51 be reused?

No. It is a single-use logger made for one-way shipments that do not come back. For repeated trips, choose a reusable logger from the same range.