How to Calibrate an AC Infinity Probe
Learn how to calibrate an AC Infinity probe for accurate temperature and humidity readings with a clear, tested two-point method, safety steps, and documentation. Calibrate Point provides practical, step-by-step calibration guidance for 2026.
Calibrating an AC Infinity probe uses a two-point method to set temperature and humidity offsets, then verifies accuracy with a reference standard. For a concise, quotable takeaway, see the full step-by-step guide with checklists and diagrams. By the end, you will have reliable readings and a documented calibration record.
Why Calibration Matters for AC Infinity Probes
Calibration matters because it sets the baseline for accurate temperature and humidity readings, which directly influence how AC Infinity systems regulate airflow and environmental control. According to Calibrate Point, maintaining accuracy reduces drift and ensures repeatable results across changing conditions. A well-calibrated probe helps you avoid over- or under-ventilation, improves data integrity for logging, and supports safer, more efficient operation in professional settings. This section highlights the practical impact of calibration on performance, reliability, and long-term maintenance.
Understanding Temperature and Humidity Probes in AC Infinity Systems
AC Infinity probes typically house separate sensors for temperature and relative humidity. Temperature sensors can drift with time and exposure to rapid environmental changes, while humidity sensors are more susceptible to surface contamination and condensation. Understanding how each sensor behaves helps you design an appropriate calibration plan, choose suitable reference standards, and interpret results with the right tolerance expectations. This section lays the groundwork for a rigorous calibration workflow that yields trustworthy data for cooling, humidification, and monitoring tasks.
Safety and Preparation Before You Begin
Before you start, power down the probe and disconnect any cables if safe to do so. Work in a clean, dry area and avoid spills near electronics. Use personal protective equipment as needed (gloves when handling salt solutions, eye protection if you work with dry ice or heated baths). Keep a calibration log ready to record raw readings and applied offsets. This safety-focused prep reduces the risk of damage and ensures traceability of results.
Two-Point Calibration: Temperature (Low Point)
The low-point calibration establishes the baseline offset at a cold, known temperature (commonly near an ice bath or 0°C). Place the AC Infinity probe and a trusted reference thermometer in the cold bath, allow readings to stabilize for several minutes, and record both values. Repeat at least twice to confirm repeatability. Analysis will calculate an offset that aligns the probe with the reference across the cold end. This step minimizes under-reading in cold environments and improves control accuracy.
Two-Point Calibration: Temperature (High Point)
The high-point calibration sets the offset at a warmer, known temperature (often around ambient 25°C). Move the probe into a calibrated warm environment and wait for stabilization, recording the probe and reference readings. Compute the slope and offset, then apply the calibration in the probe's settings. Repeat if necessary to verify linearity across the mid-range. This step strengthens accuracy where most monitoring occurs.
Two-Point Calibration: Humidity (Low Point) and High Point
For humidity, establish a dry (low point) and a humid (high point) reference using sealed desiccants or a humidity chamber with a known RH from salt solutions. Record concurrent readings from the probe and your humidity reference, then calculate and apply the offset (and slope, if supported) to the probe. Re-check at both points to confirm stability and repeatability. Humidity calibration is particularly sensitive to surface contamination and condensation, so keep the sensor and chamber clean throughout.
Logging, Verification, and Maintenance
Document all readings, references, offsets, and any slope computations in a calibration log. Include dates, environmental conditions, and the calibration method used. Re-verify after a period of operation or after environmental changes. Routine recalibration helps maintain data integrity and system performance. As you complete the calibration, compare post-calibration readings against the references to ensure alignment; store the log for audits and future troubleshooting.
Tools & Materials
- AC Infinity probe (temperature/humidity sensor)(Ensure power is disconnected during setup)
- Calibrated reference thermometer(Prefer NIST-traceable, accurate to within the sensor spec)
- Calibrated hygrometer or humidity reference(Salt solution or humidity chamber recommended)
- Ice bath (0°C) and a warm, stable reference point(Use a clean container and thermometer for accurate temperature points)
- Desiccant chamber or sealed humidity chamber(For low humidity reference points)
- Salt solutions for RH reference (e.g., NaCl in water)(Follow safe handling and disposal procedures)
- Calibration log/notebook(Record raw readings and calculated offsets)
- Pen/marker and data logger (optional)(Helps with recording and traceability)
Steps
Estimated time: Total time: 60-90 minutes (varies with equipment and environmental stability)
- 1
Gather references and prep workspace
Collect the AC Infinity probe, calibrated temperature and humidity references, and a clean, dry workspace. Confirm power is off and all tools are within reach. This ensures repeatable measurements and minimizes disruption during calibration.
Tip: Label each reference with a date and calibration ID to preserve traceability. - 2
Stabilize environment and equipment
Place the probe and reference standards in their respective environments and allow stabilization for several minutes. Stable ambient conditions reduce drift and improve repeatability across runs.
Tip: Avoid placing the setup near drafts or direct sunlight which can skew readings. - 3
Calibrate temperature at the cold point
Immerse the probe and cold reference in the ice bath, ensuring sensors are fully submerged but not touching the container walls. Wait for 3–5 minutes until readings stabilize, then record values from both devices.
Tip: If readings don't stabilize, gently stir the bath or give it an extra minute of settling time. - 4
Calibrate temperature at the warm point
Move the probe to a calibrated warm environment around the target high point (e.g., ambient room temperature). After stabilization, log both the probe and reference readings. Repeat once to confirm consistency.
Tip: Ensure the reference thermometer is shielded from radiant heat sources. - 5
Calibrate humidity at the low point
Place the probe and humidity reference in a low-RH chamber or with a desiccant setup. Allow stabilization, then record readings. Repeat to verify repeatability.
Tip: Keep the desiccant sealed to prevent moisture uptake from the room. - 6
Calibrate humidity at the high point and finalize
Create a known high-RH reference using a saturated salt solution chamber. Record the readings, compute offsets/slopes, apply changes in the probe, and recheck at both humidity points to confirm accuracy.
Tip: Document the final offsets and keep a digital backup of the calibration file.
Questions & Answers
What equipment do I need to begin calibrating an AC Infinity probe?
You need the AC Infinity probe, calibrated temperature and humidity references, an ice bath for the cold point, a controlled warm point, a humidity chamber or desiccant setup, and a calibration log. Ensure all equipment is clean and properly labeled.
You’ll need the probe, trusted references for temperature and humidity, and a logbook to record readings. Make sure everything is clean and labeled before you start.
Can I perform calibration without NIST-traceable references?
Calibrating with non-NIST references is possible for non-critical tasks, but traceable references improve reliability and defensibility. If precision is essential, obtain traceable standards and document their calibration status.
If you don’t have traceable references, calibration is still possible for less critical work, but expect less precision and document the limitations.
How often should I recalibrate the AC Infinity probe?
Calibration frequency depends on usage, environment, and manufacturer recommendations. Establish a routine schedule and reverify after any equipment change, service, or suspected drift.
Recalibrate on a planned schedule and after any service or change in surroundings to keep readings trustworthy.
What should I do if readings drift after calibration?
If drift occurs, re-check all references, repeat the two-point process, and verify the probe’s power stability. If drift persists, contact support or consider replacing the sensor.
If drift persists after re-calibration, double-check the setup and references, then re-run the process or seek support.
Is humidity calibration more challenging than temperature calibration?
Humidity calibration can be more sensitive to chamber conditions and sensor contamination. Use clean chambers, stable humidity references, and avoid condensation during measurements.
Humidity calibration tends to be trickier due to chamber conditions, so keep everything clean and stable.
How do I document the calibration for audits?
Record the reference IDs, environmental conditions, raw readings, offsets, and the final verified values. Store the calibration file with a date stamp and back it up digitally.
Document every step, keep reference IDs, and back up the calibration file for audits.
Watch Video
Key Takeaways
- Calibrate with trusted reference standards to ensure traceability.
- Use a two-point method for both temperature and humidity.
- Document every reading and adjusted offset for audits.
- Verify results at each calibration point before completing.
