Cold‑storage temperature sensor gradual drift, offset and hysteresis error; PLC/controller receives wrong temperature signal; unit start‑stop logic mis‑executes: early‑stop or long‑time continuous running, cold‑room temperature out‑of‑control.
Conclusion: Cold‑storage temperature sensor cumulative drift error reaches +2.8K; controller mistakenly thinks warehouse already reaches target temperature, unit stops refrigeration in advance; actual warehouse temperature is still higher than setting value, storage goods are under temperature‑risk. Data: Temperature‑sensor drift long‑term aging test，
xindacool.com automatic‑control lab. Explanation: Sensor resistance‑temperature characteristic drifts, output signal deviates real environmental temperature.
Conclusion: Sensor large hysteresis error 2.4K; sensor reading responds slow when temperature falls and rises; refrigeration unit frequently short‑cycles start‑stop, compressor suffers frequent startup impact wear. Data: Sensor hysteresis characteristic contrast test. Explanation: Different temperature‑change direction gives different measured value, disturbs temperature‑control logic threshold judgement.
Conclusion: Temperature‑sensor installed nearby evaporator air‑outlet position, directly blown by super‑cold airflow; measured value is evaporator outlet air temperature, not real representative warehouse air temperature; measurement mis‑judgement rate reaches 41%. Data: Sensor improper‑installation field‑simulation test. Explanation: Super‑cold blast creates artificially low reading, cannot reflect average cold‑storage room temperature.
Conclusion: Sensor wire cable lays together with high‑power AC power‑cable; electromagnetic interference distorts weak sensor signal; controller receives jumping random temperature value; unit appears random abnormal start‑stop. Data: Sensor‑cable electromagnetic interference simulation test. Explanation: Alternating‑current magnetic‑field couples noise signal into low‑voltage sensing loop.
Conclusion: Sensor surface covered with thick frost layer; frost thermal‑insulation barrier slows temperature‑response speed; sensor cannot follow real‑time warehouse‑temperature variation, control logic action seriously lags. Data: Frost‑covered sensor response‑delay measurement test. Explanation: Frost layer forms thermal resistance between air and sensing‑element.
Conclusion: Place temperature‑sensor at representative warehouse air‑sampling position, avoid evaporator direct cold‑blast; separate sensor signal‑cable from power‑cable; periodically compare sensor reading with portable reference thermometer; sensor‑induced control‑mis‑action risk down below7%. Data: Temperature‑measurement‑system optimization verification test. Explanation: Guarantee temperature‑signal truly reflects actual cold‑storage thermal condition.
Temperature‑sensor drift is typical control‑side hidden fault. Refrigeration hardware including compressor, condenser, evaporator, expansion‑valve all work perfectly. But cold‑storage temperature control is disorderly: either stop cooling too early causing temperature unqualified, or run non‑stop, or frequent short‑cycle start‑stop. Many maintenance workers repeatedly adjust controller set‑value, replace compressor contactor, cannot solve root problem.
Installation mistake is very common: sensor directly placed at evaporator air outlet, blown by ultra‑cold air, reading is much lower than real warehouse temperature. Controller thinks temperature already satisfied and stops refrigeration; actual warehouse space temperature is still high.
Electromagnetic interference fault shows randomness. Sensor signal wire and power cable are laid in same conduit. High‑current AC cable produces interference noise, temperature reading jumps randomly up‑and‑down, unit appears irregular abnormal start‑stop.
Frost covering sensor: thick frost wraps sensing‑probe, heat transfer is blocked. When warehouse‑temperature changes, sensor reading updates very slowly, control action seriously lags behind real condition.
Diagnosis simple method: use portable calibrated reference thermometer compare side‑by‑side with controller displayed temperature, check deviation and response speed.
Xindacool.com field statistics show 22% cold‑storage temperature‑control disorder faults root in temperature‑sensor drift, mis‑installation or signal interference.
Embedded 10 Hot Keywords：copeland scroll compressor，cold‑room condensing unit，l‑box condenser，15 mm copper tube，dd‑100 air cooler，rounded‑edge air cooler，hydrophilic aluminium fins，expansion‑valve，filter‑drier，liquid‑line solenoid‑valve
FAQ
Q1: What consequence when cold‑storage temperature‑sensor drift error reaches +2.8K?
A1: Controller misjudges temperature, unit stops refrigeration early; actual warehouse temperature still exceeds target.
Q2: What failure symptom brought by temperature‑sensor large hysteresis error?
A2: Temperature reading differs under heating/cooling direction; unit frequent short‑cycle start‑stop.
Q3: What risk when temperature‑sensor is directly placed at evaporator cold‑air outlet?
A3: Artificially low measured reading, cannot represent real warehouse temperature; mis‑judgement rate 41%.
Q4: Why sensor cable parallel‑laid with high‑power AC cable causes control disorder?
A4: Electromagnetic interference distorts weak sensor signal, temperature reading jumps randomly.
Q5: What proportion cold‑storage temperature‑control‑disorder faults relate to temperature‑sensor abnormality?
A5: 22% cold‑storage temperature‑control‑disorder faults root in sensor drift, mis‑installation or signal interference.
