All three versions share the same hardware and optical chain. The difference is in the level of metrological preparation before shipment: 
• Standard: Factory-calibrated under reference conditions (Arizona test dust). Ready for integration, good general accuracy. 
• Verified: Individual units selected and verified against a reference instrument. Deviation < 20% on PM2.5. Includes a numbered certificate of accuracy per serial number. Required for institutional deployments, public tenders, or applications needing formal traceability. 
• Adjusted: Each unit individually calibrated at 3 PM concentration levels. Deviation < 10% on PM2.5. Includes an individual calibration certificate. Recommended for R&D, multi-sensor comparisons, or environments where particle composition differs significantly from Arizona dust (coastal, industrial, underground).

💡 Certificates are shared by TERA via a dedicated drive per customer after delivery.

NextPM uses an internal fan for air sampling and is optimised for concentrations up to ~1,000 µg/m³. NextPM Advanced uses an external pump instead of a fan, which provides two advantages: it supports concentrations up to 10,000 µg/m³, and it handles pressure constraints that would prevent an internal fan from working correctly — for example, pressurised ducts or sealed enclosures. The internal measurement chain is identical in both versions. NextPM Advanced is recognisable by its visible inlet tube on the top of the unit.

💡 For environments where PM10 regularly exceeds 500 µg/m³ (mining, heavy industry, certain manufacturing lines), NextPM Advanced prevents saturation and preserves automation logic integrity.

Yes. Thanks to dual-angle photodetection and the 5-bin granulometric signature, NextPM can distinguish vaping aerosol from other particle sources based on particle size distribution. TERA provides the detection algorithms — no additional R&D is required from the integrator. This capability is used in school restrooms, public buildings, and workplace air quality systems where discreet, embedded detection is preferred over dedicated vaping sensors.

There is no native PM4 output, but it can be calculated. Retrieve the raw particle count for the 2.5–5 µm bin via Modbus (1-minute average registers), then apply TERA’s official mass conversion coefficient (0.0113097) and add the result to the PM2.5 µg/m³ value. This calculation can be performed directly in the integrator’s MCU. If raw bin counts have been logged historically, PM4/PM5 can be recalculated retroactively without redeployment.

The mean time to failure (MTTF) is approximately 15,000 hours of continuous operation (roughly 2 years), primarily limited by the laser diode. Very high dust concentrations accelerate drift. Sequential use (sleep mode between measurement cycles) significantly extends lifespan. The anti-clogging inlet design is a key differentiator — NextPM is the only PM sensor with a patented inlet geometry specifically designed to limit fouling over time.

💡 Monitor the clogging PM10 register (cumulative particle load since commissioning) to anticipate end of life and schedule proactive replacements.

NextPM requires +5 VDC. The practical minimum is 4.8V — below this, measurement artifacts may appear, especially in outdoor deployments. Do not power NextPM from a depleted LiPo battery (4.2V) in critical applications. Note that despite the 5V supply, all communication signals are 3.3V TTL logic.

NextPM uses a Molex PicoBlade 6-pin connector (Molex ref. 15134-0600, available from Mouser, DigiKey, RS Components). For direct UART integration, use a cable with PicoBlade on one side and flying leads on the other. Pin mapping: Pin 1 = GND, Pin 2 = +5V, Pin 3 = TX (sensor output → MCU RX), Pin 4 = RX (sensor input → MCU TX), Pin 5 = CS. Note that TX/RX are crossed — sensor TX connects to host RX.

💡 If the fan does not start on power-up, the most common cause is incorrect Molex connector orientation, not a software issue.

The inertial inlet filter requires correct orientation with respect to gravity to function as designed. Particles heavier than 10 µm must be able to impact the filter wall naturally. Incorrect orientation can compromise PM10 filtering. Refer to the integration guide in the TERA GitBook (tera-sensor.gitbook.io/tera-sensor/sensors/nextpm) for the recommended mounting diagram. Always ensure that inlet and outlet are at equal pressure — pressure imbalance prevents the internal fan from maintaining correct airflow.

Use antistatic tubing to prevent electrostatic particle deposition before the measurement zone. Straight runs are preferred — a 1-metre straight tube causes approximately 20–30% losses on PM10 (less on PM2.5, negligible on PM1). If a 90° bend is unavoidable, keep it short and smooth. Test with and without the bend on two units in parallel to quantify real losses. For the protective inlet grille, use ~1mm mesh in stainless steel for outdoor deployments.

TERA commonly uses the DSD Tech SH-U12 (MAX13487 chip), available on Amazon. It is simple to use and compatible with NextPM in half-duplex mode. Note that the PCB is not conformal coated — avoid using it in high-humidity or outdoor environments without additional protection. For production deployments, the recommended approach is to integrate the RS485 transceiver directly on the integrator’s PCB rather than using an external module.

On firmware 0x1042 and earlier, sleep mode is triggered via the simplified (non-Modbus) protocol using a toggle command. The same command alternates between sleep and wake states. After waking, wait 15 seconds before reading measurements (fan restart and optical path stabilisation). Modbus-native sleep control will be available from firmware 0x1048 onwards. Always read the status register before sending a sleep command to confirm the current state and avoid inadvertently waking a sleeping sensor.

💡 Sleep mode is the most effective way to extend NextPM lifespan in deployments where continuous measurement is not required — for example, 5-minute measurement windows every hour

Apply a multiplier of 10⁻³ to convert raw register values to µg/m³ (for mass fractions) or counts/litre (for particle count bins). This coefficient is identical across all PM registers. If PM1 appears higher than PM2.5 in your readings, this is almost always a register addressing or byte-order (MSB/LSB) error in the integration, not a sensor hardware fault. Verify with the TERA Windows GUI software connected via FTDI cable to isolate the issue.

Less than most OEM sensors at this price point, thanks to the built-in inlet heater. The heater activates automatically when relative humidity exceeds 65%, shifting from 0% to 100% duty cycle progressively. At RH > 90%, some overestimation may still appear on PM2.5, though the effect is significantly smaller than on sensors without humidity compensation. PM10 is less affected. For critical applications in consistently high-humidity environments, applying a correction slope via the dedicated Modbus calibration registers is recommended.

NextPM uses generic mass conversion factors calibrated on Arizona test dust. Real-world particle composition varies by environment: urban, coastal, desert, industrial, and underground environments all have different particle densities and refractive indices, which affect the optical-to-mass conversion. This is not a sensor defect — it applies to all optical PM sensors, including expensive reference instruments. The solution is to co-locate NextPM with a reference instrument for a calibration period and apply a slope correction via the Modbus coefficient registers.

At concentrations approaching the upper measurement limit, coincidence effects occur: multiple particles cross the laser beam simultaneously and are counted as a single event, causing underestimation. For the standard NextPM, this effect becomes significant above ~1,000 µg/m³. For consistently high-concentration environments (mining, foundries, certain battery manufacturing processes), NextPM Advanced with its extended 10,000 µg/m³ range is the appropriate choice.

NextPM carries CE and RoHS certifications. TERA has also conducted third-party testing against CEN/TS 17660-2, achieving Class 1 for PM2.5 and Class 2 for PM10 (results are non-public but available upon request under NDA). SafyrOPC is certified to ISO 21501-4. TERA has not pursued MCERTS certification as the standard is evolving towards CEN/TS 17660-2, and certification in this category applies to the final integrated product rather than the sensor component alone.

Sensor SafyrOPC is a true Optical Particle Counter (OPC) measuring particle count in 5 channels: > 0.3 µm, > 0.5 µm, > 1.0 µm, > 2.5 µm, > 5.0 µm — all expressed in particles per cubic metre (pcs/m³). It also measures temperature and humidity. Flow rate is 2.83 L/min. Three averaging periods are available: 10 seconds, 1 minute, and 15 minutes. Unlike NextPM which expresses outputs in mass concentration (µg/m³), Sensor SafyrOPC outputs particle count — the standard unit for cleanroom classification.

Yes. Sensor SafyrOPC is calibrated against ISO 21501-4 standards using monodisperse latex spheres (NIST-traceable). Each unit includes an individual factory calibration certificate valid for 1 year. The calibration bench used for ISO 21501-4 compliance is the standard for optical particle counters used in cleanroom classification and monitoring.

💡 Annual renewal is done by sensor replacement, not recalibration. TERA supplies a new factory-calibrated unit with a fresh ISO 21501-4 certificate — faster than a recalibration, no equipment downtime, no return logistics, and you always get the latest sensor version. Contact your TERA distributor to set up an annual replacement schedule.

Sensor SafyrOPC is designed for continuous real-time monitoring in ISO 5–8 cleanrooms and GMP Grade B, C, and D environments (pharmaceutical, biotechnology, medtech, hospital, microelectronics, aerospace). For GMP Grade A — the highest cleanliness class requiring transient event capture as specified in GMP Annex 1 — a certified reference counter with a higher flow rate is the appropriate tool. SafyrOPC is not excluded from Grade A environments for supplemental monitoring, but it cannot serve as the primary Annex 1 compliance instrument.

Sensor SafyrOPC communicates via RS485 Modbus RTU through a 6-pin connector. Pin 1 = GND, Pin 2 = DE/RE (direction enable for RS485 transceiver), Pin 3 = Rx (input), Pin 4 = Tx (output), Pin 5 = +5V, Pin 6 = GND. Power supply is +5 VDC, < 70 mA average. It can be integrated into any Modbus-compatible cleanroom monitoring platform, SCADA, or EMS. Multiple Sensor SafyrOPC units can be networked on a single RS485 bus.

Sensor SafyrOPC measures up to 3.3 × 10⁹ particles/m³ (channel 1, > 0.3 µm). Above this threshold, coincidence effects lead to loss of linearity — multiple particles crossing the laser simultaneously are undercounted. In practice, this limit is well above the particle concentrations typically found in ISO 5–8 cleanrooms. The high-efficiency discharge filtration (patented) prevents contamination of the optical chamber from the exhaust.

MTTF is 10,000 hours. In a cleanroom environment with continuous operation, this corresponds to approximately 14 months. In deployments using normal measurement mode (one measurement every 15 minutes), lifespan is significantly extended. TERA recommends annual calibration coincide with a lifespan check. The sensor unit within the SafyrOPC instrument system is designed to be replaced annually.

Yes. Semiconductor fabrication facilities require particle monitoring at ISO 5 and below (equivalent to Class 100 or better). Sensor SafyrOPC’s 0.3 µm detection threshold makes it appropriate for environments where sub-micron particle contamination is critical — for example, wafer handling, lithography areas, and thin film deposition zones. The Modbus RS485 output integrates with fab-level monitoring systems and equipment interfaces.

No. The smallest detectable particle diameter is 0.3 µm. Particles below this threshold (nanoparticles, ultrafine particles < 0.1 µm) are not detected by Sensor SafyrOPC or any standard OPC. For environments requiring sub-0.3 µm monitoring (advanced semiconductor nodes, specific pharmaceutical applications), dedicated condensation particle counters (CPCs) or differential mobility analysers (DMAs) are the appropriate instruments.

No — and this is a critical regulatory distinction. Periodic audits with reference instruments are mandatory for ISO 14644 classification and GMP Annex 1 compliance certification. SafyrOPC continuous monitoring serves a different and complementary purpose: it detects contamination events between those scheduled audits. Regulatory audits cover only a fraction of actual production time. The majority of contamination events occur between audits and go undetected until the next certification visit — potentially after product has already been manufactured and released. Continuous monitoring provides the operational visibility that periodic certification cannot.

💡 The contamination timing argument is the central case for SafyrOPC in GMP environments: audits certify the room at a moment in time, but they do not protect the process during the weeks or months between audits.

SafyrOPC supports two wireless modes:

LoRa (Long Range): communicates with the SafyrOPC Receiver hub via a proprietary TERA protocol. LoRa is designed for large facilities — it penetrates walls and floors where Bluetooth or WiFi would fail. The Receiver provides a Modbus RTU output (M12 connector) for integration with BMS, SCADA, or centralised monitoring platforms. Multiple SafyrOPC sensors can be networked through a single Receiver.

Bluetooth Low Energy (BLE): enables direct connection to a smartphone or tablet for local real-time readout, and to a remote display for on-site visualisation of particle counts. Useful for spot checks, commissioning, or areas where a fixed monitoring infrastructure is not yet deployed.

Most competing in-duct sensors use a passive fan that is essentially driven by duct airflow. At high duct velocities, the fan overspeeds; at low velocities, it underspeeds — in both cases, particle collection efficiency degrades and PM10 data is unreliable. PMDuct uses an active internal pump that maintains a stable internal flow rate (1.2 L/min) regardless of duct air speed. This makes PM10 measurements representative across the full 1–5 m/s operating range tested in laboratory conditions on an AHU.

💡 Beyond 5 m/s duct velocity, contact TERA for a specific evaluation.

PMDuct measures PM1, PM2.5, and PM10 from 0 to 10,000 µg/m³. As with NextPM Advanced at its core, PM10 is derived from actual particle count data across 5 bins (0.3–10 µm) — not estimated from PM2.5 as most competing sensors do. This matters significantly in environments where coarse particle distribution is irregular, such as post-filter failure events in HVAC systems.

Yes. PMDuct communicates natively via Modbus RTU over an M12 connector — the industrial standard for PLC integration. Unlike sensors offering only analogue outputs (4–20mA or 0–10V), PMDuct’s digital Modbus bus provides the full granulometric dataset (PM1, PM2.5, PM10, particle counts by bin) directly to the automation system without signal conditioning. Compatibility with the majority of industrial PLCs (Siemens, Schneider, Allen-Bradley, etc.) and SCADA platforms is straightforward via standard Modbus drivers.

PMDuct is installed by inserting the probe through the duct wall at any accessible point in the air handling unit — typically downstream of filters to monitor filtration performance, or in the supply/return air stream. The M12 connector allows clean cabling through the duct wall. No cutting of the duct is required beyond a standard port hole. Measurement frequency in normal mode is one measurement every 15 minutes; forced continuous mode is available where process monitoring requires it.

NextPM is an OEM sensor module designed for integration into larger IoT systems. Its Modbus RS485 protocol is compatible with standard industrial communication architectures. Multiple NextPM units can be networked on a single RS485 bus across large production floors, with data aggregated centrally. The 5-bin granulometric data per sensor enables distributed particle size mapping — a capability beyond simple PM2.5/PM10 monitoring — allowing process engineers to identify contamination sources by particle signature rather than just concentration.

For lithium-ion manufacturing, the most critical particles are typically in the 1–10 µm range (electrode coating defects, metal debris from calendering rolls) and the 0.3–1 µm range (aerosol contamination in dry rooms and electrolyte filling). NextPM’s 5 bins cover this full range. For separator integrity, particles above 5 µm are of particular concern. TERA can advise on sensor placement and bin-level alerting thresholds based on your specific process chemistry and cell format.

No. NextPM does not have a user-accessible bootloader (memory constraint). Firmware updates must be performed by TERA. Return the sensor or contact TERA support to arrange an update. TERA will advise whether an update is warranted based on your application and current firmware version.

Yes. TERA provides a free Windows GUI application that reads all registers in real time via a USB FTDI cable. The software and FTDI driver download links are available at tera-sensor.gitbook.io/tera-sensor/sensors/nextpm/software. If the download link is temporarily unavailable, contact TERA to receive the file directly. If the software displays ‘access denied’, verify the correct COM port is selected in Windows Device Manager.

TERA Sensor works with a network of regional distributors: ION Sense (United Kingdom), Tecnosens (Italy), Svan (India), and Xuzhou ZhiDing (China). NextPM is also available globally through DigiKey (ref: 004-BU-OEM-Next-PM) and RS Components (ref: 1953770) for direct order by integrators and developers.

There is no strict minimum order quantity for evaluation purposes. Volume pricing tiers start at 1–99 units, 100–499, 500–999, and 1,000+ units. For R&D or pilot integrations, single units are available. For OEM integration projects at volume, contact TERA to discuss pricing, delivery, and technical support arrangements tailored to your project timeline.

Standard NextPM units are generally available from stock or with short lead times. NextPM Verified and Adjusted require additional preparation time due to the individual calibration process. For volume OEM orders, lead times are project-dependent. Contact TERA at sales@groupe-tera.com for current availability and a formal quote.

Yes. TERA offers calibration services at the time of manufacture (Standard, Verified, Adjusted tiers) and can perform recalibration on returned units. For units deployed in environments that differ significantly from Arizona test dust conditions (coastal, industrial, underground), TERA can advise on field correction procedures using the built-in slope/offset Modbus registers, which can be adjusted by the integrator after co-location with a reference instrument.

Email: sales@groupe-tera.com | Phone: +33 6 43 11 36 52 | Web: tera-sensor.com | Technical documentation: tera-sensor.gitbook.io/tera-sensor. For integration-specific questions, TERA’s technical team can arrange a 15-minute video call to review your project requirements and confirm which product configuration is appropriate.