Cold Storage Temperature & Humidity Monitoring: Data Loggers, Transmitters and Controllers (Q&A)
Short answer: use a controller to run the room, a transmitter with a 4-20 mA, 0-10 V or RS485 output when you need live alarms in a PLC or building system, and a self-contained data logger when you must prove the temperature of a load or a room afterwards. Always check that the listed measuring range covers your coldest set point. Below are the questions to answer before buying, with examples from our catalog (specs quoted from each product page).
What should I monitor in a cold room, walk-in cooler or freezer?
At minimum, air temperature at the warmest point of the room (usually near the door and the top shelves). Add relative humidity when the product is sensitive to drying or condensation (produce, cheese, cured meat, paper and electronics), and keep a recorded history if a customer, auditor or insurer may ask you to prove the temperature during storage or transport.
What is the difference between a data logger, a sensor/transmitter and a controller?
A data logger records readings on its own memory so you can export a report later. A sensor or transmitter sends a live signal (analog, RS485 or wireless) to a PLC, BMS or app. A controller reads a probe and switches a relay to turn a compressor, heater, humidifier or dehumidifier on and off. Many sites use all three: a controller to run the room, a transmitter for live alarms and a logger as independent proof.
Which device on this page covers freezer temperatures?
Check the measuring range on the product page before buying. The SUNRI Bluetooth data logger lists -30 to 70 °C and the Atech AHTS-3 duct transmitter lists a standard range of -30 to 70 °C (or 0 to 50 °C). The LILYTECH ZL-7816A controller lists 0.0 to 80.0 °C, so it is for rooms above freezing, not freezers.
How do I get a temperature record for a shipment?
Place a self-contained logger inside the load. The SUNRI logger stores up to 65,000 points, lists ±0.5 °C accuracy, and exports a PDF report through a phone app over Bluetooth or when connected to a computer. Its page describes it as a one-time-use recorder with a built-in, non-replaceable 3.0 V battery rated up to 6 months under typical use.
Can I connect a temperature and humidity sensor to a PLC or building management system?
Yes, with a transmitter that has an industrial output. The Atech AHTS-3 duct-type sensor lists 0-2 V, 0-5 V, 0-10 V, 4-20 mA and RS485 outputs, 0-100 %RH (non-condensing), and ±0.2 °C / ±3 %RH accuracy. Confirm the output you need when you order; we can check it with the supplier before shipping.
How do I control humidity in a curing, ripening or storage room?
Use a hygrostat that switches a humidifier or dehumidifier. The LILYTECH ZL-7830A lists a 0-100.0 %RH setting range, 0.1 %RH resolution, a 30 A / 250 VAC relay output (resistive load), 100-240 VAC supply and an IP65 front panel; its page mentions sausage and cheese rooms with the optional ZL-SHr05B sensor. The ZL-7816A controls temperature and humidity separately on 12 V AC/DC with a 7 A relay.
Comparison: devices in our catalog
Specifications are quoted from each product page. Prices are current site prices in USD.
| Product | Listed specifications | Best fit | Price |
|---|---|---|---|
| SUNRI Bluetooth temperature data logger (ABX-0665) | -30 to 70 °C, ±0.5 °C, 65,000 points, PDF export, one-time use | Shipments and cold-chain records | $34.10 |
| Atech AHTS-3 duct temperature & humidity transmitter (ABX-0651) | -30 to 70 °C or 0 to 50 °C, 0-100 %RH, ±0.2 °C / ±3 %RH, 0-10 V / 4-20 mA / RS485 | PLC, BMS and HVAC ducts | $256.20 |
| LILYTECH ZL-7816A temperature & humidity controller (ABX-0585) | 0.0-80.0 °C, 0.0-99.9 %RH, 12 V AC/DC, 7 A relay | Coolers and rooms above 0 °C | $34.76 |
| LILYTECH ZL-7830A humidity controller (ABX-0580) | 0-100.0 %RH, 30 A / 250 VAC relay, 100-240 VAC, IP65 front | Curing, ripening and storage rooms | $70.09 |
| Digital humidity controller 110-220 V (ABX-0608) | 0-99 %RH control range, 0.1 %RH, max 10 A | Warehouses and greenhouses | $28.86 |
| Zigbee 3.0 temperature & humidity sensor, Tuya (ABX-AE-794088) | Zigbee 3.0, needs a compatible gateway | Phone alerts for storerooms and server closets | $17.99 |
| Mini dial thermometer-hygrometer (ABX-0681) | -30 to 50 °C ±2 °C, 10-100 %RH ±5 %RH (40-70 %RH) | Quick visual check, no power needed | $9.01 |
Is a Zigbee or smart-home sensor good enough for a business?
For offices, storerooms, server closets and greenhouses where you want phone alerts, a Zigbee 3.0 sensor on a Tuya / Smart Life gateway is a low-cost option. Its product page does not list a measuring range or accuracy, so for freezers, regulated goods or audit records use a logger or transmitter with published specifications.
Do these devices come with calibration certificates?
None of the product pages linked here list a calibration certificate. If your food-safety, pharmaceutical or quality program requires certified calibration, ask us before ordering and plan an independent calibration check.
Where do you ship and how much does shipping cost?
Shipping is free within the United States. We also ship to Latin America and the Caribbean (20% of the order subtotal, minimum $25). Texas orders include 8.25% sales tax. Delivery time depends on the supplier of each product; ask us for an estimate before you order.
Need help choosing or a quote for several rooms?
Tell us the number of rooms or vehicles, the set points and how you need the data (app, PLC, PDF report). Use the quote request form or write to solutions@automationbotx.com.