AbhilekhCold rooms & large sites · 2–8 °C · −20 °CCold room and walk-in chamber monitoring
A walk-in cold room has a warm corner near the evaporator return, a cold spot under the fan, and a door that someone props open on a busy dispatch day. One sensor in the middle of the room proves none of that.
Cold rooms concentrate risk: high inventory value in a single controlled volume, a defrost cycle that deliberately warms part of that volume on a timer, and human traffic through a door that is the single biggest source of thermal load. The mapped extremes are usually the air return, the zone directly in the fan stream, the floor-level corner furthest from the evaporator, and the doorway.
The monitoring design follows the mapping. Each of those positions needs its own measuring point at product height, sampled fast enough to resolve a defrost cycle, and correlated with door and power events so that a warm half-hour has an explanation attached to it rather than a question mark.
One ABH-300 industrial unit carries four Class-A PT100 channels plus on-board temperature, humidity and barometric pressure, which means a mapped cold room is often one instrument and four probes instead of four instruments — fewer calibration certificates to manage and one clock for every channel.
The expectations behind the record
What an inspector or auditor looks for in this use case, and the framework each expectation comes from.
Initial mapping, then re-mapping on a risk basis
Temperature distribution is established before use under representative load, and repeated at defined intervals and after any change to the refrigeration plant, racking or airflow. Permanent sensor positions are justified from that study.
Qualification as DQ, IQ, OQ and PQ
Design qualification defines the user requirement, installation qualification proves the room was built to it, operational qualification demonstrates empty mapping and alarm function, and performance qualification runs loaded over a representative period including door openings and a simulated power failure.
Alarms that are tested, documented and routed
Alarm set points, delays, escalation paths and the evidence that each was challenged during OQ belong in the qualification package — an untested alarm is not a control.
Channel-level calibration traceability
Every measuring channel carries its own traceable certificate and due date. In a multi-channel instrument that means per-probe records, not one certificate for the box.
The failure modes nobody budgets for
Every one of these is a real reason monitoring programmes lose their audit trail — or lose the trust of the people who work with them.
Defrost cycles that look like failures
Scheduled defrost warms the evaporator zone by design. Without event context, every cycle generates an excursion that QA has to close out manually — until someone widens the limits and hides a real fault.
Radio that will not leave a metal box
An insulated panel cold room is close to a Faraday cage. A monitor mounted inside with an internal antenna is a support ticket waiting to happen.
Four instruments, four clocks, four certificates
Single-channel loggers at four mapped positions mean four calibration cycles, four battery schedules, and timestamps that drift apart just enough to make correlation awkward.
Power failure evidence nobody captured
The question after an outage is always the same: how warm did it get, for how long, and was the product affected. That answer has to survive the outage that caused it.
Engineered for this, specifically
Each point below maps to a documented platform behaviour — not a marketing promise.
Four mapped positions, one instrument, one clock
ABH-300 takes four Class-A PT100 channels (±0.15 °C at 0 °C) plus on-board T/RH and barometric pressure, so the mapped extremes share a single timebase and a single audit record.
The antenna leaves the room, the probes stay in
ABH-200-LR accepts an external SMA dipole so the radio has line of sight outside the panel while the sensing element stays at product height inside. Where the site has no Wi-Fi at all, ABH-200-C connects over LTE.
Defrost and door events as first-class data
Stateful rules evaluate duration and area-under-curve, so a predictable defrost window is characterised rather than alarmed, while an unexpected warm period of the same magnitude escalates.
Outage evidence written before the outage ends
Logging continues into on-device flash — up to 409,600 readings, CRC-checked, plus a never-erased audit region — and backfills into the SHA-256 chain when power and network return, with the gap itself recorded as an event.
Mapping studies with the same instruments you monitor with
The ABH-300 units used for a mapping study are the same platform that stays behind for routine monitoring, so the study and the ongoing record share a data model and a reporting format.
The ABH loggers for this job
Abhilekh runs its own logger line end to end — one manufacturer owns the chain from probe accuracy to the signed record.
- ▸PRB-PT100-3W — Class-A immersion probe, 3 m / 5 m / 10 m cable options
The ABH line is at the design-frozen, pre-production stage. Every battery-life, drop, thermal and IP figure is a calculated or simulated design estimate, and the regulatory marks referenced on this site are a certification roadmap — not held certificates.
Questions, answered
Other environments we monitor
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