HACCP temperature logging in cold rooms and freezers

Logging intervals, alarm delays, sensor placement and data retention for cold rooms and freezers, and which ICP DAS hardware fits each task.

Publisert 28. oktober 2026

HACCP temperature logging in cold rooms and freezers has two jobs: warn staff early enough to save the goods, and produce records that show what happened and what was done about it. This article covers what to measure and document, how to set logging intervals and alarm delays, where to place sensors, how to keep data through power and network failures, and which ICP DAS sensors, I/O modules, edge controllers and software fit. Critical limits, monitoring frequency and retention periods come from your HACCP plan and the rules for your sector, so check the requirements that apply to your business.

What to measure and record for HACCP temperature logging

Most systems measure air temperature in each cold room and freezer. Air temperature reacts quickly to door openings and defrost cycles, while the product changes slowly, so some sites add a probe in a product simulant to get a reading closer to the product. Humidity is worth measuring where condensation or ice build-up is a concern.

For each measuring point, the records usually need:

A point name that matches the HACCP plan, for example "Freezer 2, rear left"
The measured value with a date and time stamp from a synchronised clock
Alarm events with start, end, peak value and duration
Who acknowledged the alarm and which corrective action was taken
Gaps caused by sensor faults or communication loss, marked rather than hidden
Calibration or verification dates for each sensor

Logging interval and alarm delay

The logging interval should be short enough to show when an excursion started and how long it lasted. Alarms should not simply follow the logged value: a door opening can raise the air temperature for a few minutes without risk to the product, and an alarm on every peak teaches staff to ignore alarms. A common approach uses separate levels, each with its own delay:

Level	Condition	Typical action
Warning	Above a pre-alarm value for longer than a short delay	Local indication and a message to the shift
Alarm	Above the critical limit for longer than the set delay	Siren, e-mail to the on-call person, corrective action recorded
Fault	Sensor open circuit or no data received	Message to maintenance, gap marked in the records
Defrost	Planned defrost cycle running	Longer delay for that period only, not a disabled alarm

Sensor placement in cold rooms and freezers

Avoid the air stream directly in front of the evaporator and the area just inside the door. Both show extremes that do not represent the room.
Place the reference sensor where the room is warmest in normal operation. A temperature mapping of the empty and loaded room is the reliable way to find it.
Keep sensors clear of walls, lights and direct contact with goods, and protect cables from pallets and forklifts.
Large rooms or rooms with several evaporators may need more than one point.

The operating range of the electronics matters as much as the sensor range. CL series loggers operate from 0 to 50 °C in an IP20 housing, so they belong in packing areas, not inside cold rooms. The DL-100TM485S logger has an IP66 housing and operates from −20 to +60 °C, which suits chilled rooms. For freezers, a Pt100 or Pt1000 probe inside, wired to an RTD input module mounted outside, keeps the electronics out of the cold. The M-7015-G and M-7033-G RTD modules detect an open wire, so a broken probe shows up as a fault, not a wrong value.

Data retention, power loss and network loss

Keep the data in more than one place: a logger with internal memory continues recording when the network is down, and a central database holds the archive, sized with backups for the retention period your requirements set.

Worked example: buffer time of local memory

The DL-100TM485S stores up to 4,088 temperature and humidity records at an interval from 10 seconds to 1 day, and can be set to overwrite or to stop logging when the memory is full. At a 5-minute interval, 4,088 × 5 minutes is 20,440 minutes, or about 14 days. At a 1-minute interval it is under 3 days. Local memory is a buffer for outages, and the records must be collected regularly. The DL-100S-E (600,000 records) and the CL series (450,000 records) give a much longer buffer.

For power loss, put the edge controller and the PoE switches on a UPS, so PoE-powered loggers stay up as long as the switch does. For network loss, the central system should raise a fault when a point stops reporting, not only when a value is too high. During commissioning, disconnect power and network on purpose and check clock, records and alarms afterwards.

Which ICP DAS products fit

Role	Products	Relevant data
Logger in chilled rooms	DL-100TM485S, DL-100TM485PS	IP66, LCD, Modbus RTU over RS-485, −20 to +60 °C, ±0.4 °C typical (±0.3 °C for the P version)
Logger on Ethernet	DL-100S-E	IP66, Modbus TCP and MQTT, PoE, 600,000 records
Compact sensor	DL-10	Temperature, humidity and dew point over Modbus RTU, 3 m cable, −25 to +75 °C
RTD probes in freezers	M-7015-G, M-7033-G, PET-7015	Pt100 and Pt1000 inputs, open-wire detection; PET-7015 adds PoE and Modbus TCP
Many points on one cable	M-7004-G	Up to 20 DS18B20 sensors per port; ±0.5 °C is specified between −10 and +85 °C, so check accuracy at freezer temperatures
Small sites	WISE-7115	7 RTD inputs, PoE, IF-THEN-ELSE rules and e-mail; no data logger listed, so pair it with one
Edge controller	WISE-5231	Reads M-7000, DL, CL and ET-7000 modules, data logger on microSD, e-mail, SNMP trap, MQTT, SNTP time synchronisation
Database and reports	IoTstar	Imports WISE controller data into MS SQL, MySQL or Oracle; dashboards and reports
Local alarm	ALM-Horn-RGB, ALM-04-MRTU	Siren with RGB LEDs over PoE and Modbus TCP; MP3 voice messages over Modbus RTU

Send us your list of cold rooms and freezers with their set points, and our technical sales team will propose sensors, logging and alarm handling.

Produkter for dette bruksområdet

PET-7017-10 CR PET-7017-10 PoE Ethernet I/O Module, 10/20-ch Analog Input

The PET-7017-10 is a PoE-powered Ethernet analog input module for engineers who need voltage or current measurement on a networked I/O node. Its inputs can be set as 10 differential or 20 single-ended channels in software, and each channel can be given its own range, so one module can serve mixed sensor types on the same network.Each channel offers a choice of voltage ranges from ±150 mV to ±10 V and current ranges of ±20 mA, 0 ~ 20 mA and 4 ~ 20 mA, selected with jumpers. Resolution is 16-bit, and the module has two sampling modes: normal mode at 10 Hz total and fast mode at 50 Hz total. Open wire detection is available for 4 ~ 20 mA inputs, and differential channels are rated for 240 Vrms overvoltage protection.Configuration and monitoring are handled through a built-in web server with Web HMI, and the module supports Modbus TCP and Modbus UDP. Access is controlled by ID, password and IP filter. The unit is powered either from PoE (IEEE 802.3af, Class 1) or from a +12 ~ +48 VDC terminal block, and it mounts on a DIN rail.ApplicationsBuilding automationFactory automationMachine automationRemote maintenanceRemote diagnosisTesting equipment

2 971,11 kr per stk. · mengderabatt fra 10 stk.

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AR-200 CR AR-200 Accelerometer Data Logger, 2-ch IEPE Input

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6 233,10 kr per stk. · mengderabatt fra 10 stk.

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AR-400 CR AR-400 Accelerometer Data Logger, 4-ch IEPE Input

The AR-400 is a dynamic signal acquisition module for vibration monitoring and analysis. It samples four channels simultaneously with 16-bit resolution and supplies a built-in 3 mA excitation current for IEPE accelerometers, so compatible sensors can be connected directly without an external supply.Acquired data is written to a micro SDHC card (4 to 32 GB), allowing offline analysis after capture. Recording can be started by push button, schedule, analog threshold, digital input or remote trigger from the utility software installed on a host PC, which also handles sample rate and sampling schedule settings.Suited to condition monitoring setups where vibration data must be captured at defined times or on defined events.Includes a relay output (Form A, 5A@250 VAC) and a digital input for use within trigger or control logic.ApplicationsVibration monitoring and analysisIndustrial automationFactory automationProcess automation

7 116,12 kr per stk. · mengderabatt fra 10 stk.

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CL-202-E CR CL-202-E CO2/Temperature/Humidity Data Logger, RS-485 and Ethernet PoE

CL-202-E CR is a data logger module for monitoring indoor air quality and climate conditions. It measures CO2 with a non-dispersive infrared (NDIR) sensor, alongside temperature, relative humidity and dew point, and records the results with date and time stamps for later analysis.The module offers an RS-485 port and an Ethernet port with PoE support, so it can be integrated into existing HMI or SCADA systems over DCON, Modbus RTU, Modbus TCP or MQTT. Real-time readings can be viewed from the iAir Utility, the iOS or Android apps, or a web browser, provided the logger is on the same local network. Logged data can be exported to CSV for analysis in standard spreadsheet or industry software.Relay output for alarm signalling or control of IAQ equipmentCeiling or wall mounting, IP20 housing, Ø 150 x 53 mmOperating temperature 0 ~ 50°C, non-condensing humidity range 10 ~ 90% RHApplicationsTransportation of food or pharmaceuticalsFood and beverage industry (HACCP)Blood stations and pharmaciesBuilding and energy managementWarehouse managementMuseums, archives and galleriesIndoor or underground parking lot air quality monitoring

4 124,23 kr per stk. · mengderabatt fra 10 stk.

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