Industrial online near-infrared moisture meter, 4-20mA/RS485 signal interfacing with PLC - AMT/SFY-HW

Industrial online near-infrared moisture meter, 4-20mA/RS485 signal interfacing with PLC

1. Solution Overview

Online near-infrared (NIR) Moisture monitoring system, relying on the selective absorption characteristics of water molecules for specific near-infrared band spectra, using non-contact, non-destructive continuous detection method, real-time collection of material moisture content on the production line, data connected to PLC, central control system, realizing online moisture monitoring, over-limit alarms, and closed-loop regulation of drying process. Replacing traditional manual sampling + Oven testing, solving pain points such as testing lag, missed detection in sampling inspection, and large manual errors, suitable for various continuous solid material production lines such as belt conveying, chutes, screws, pipelines, and silos, helping production quality improvement, energy saving and consumption reduction, and traceable quality data Douyin Baike.

2. Measurement Principle

The near-infrared light source emits infrared light of a specific wavelength to illuminate the material, and water molecules will absorb near-infrared light in a specific band; the detector receives the spectral signal diffusely reflected back from the material, and through the built-in spectral algorithm and temperature compensation model, deducts interference from material color, particle size, and ambient temperature, and converts the material moisture content in real time.

Features: non-contact, no damage to materials, millisecond-level output, no need for sampling and sample preparation, continuous uninterrupted measurement.

Industrial online near-infrared moisture meter, 4-20mA/RS485 signal interfacing with PLC

3. System Composition

The entire online near-infrared moisture monitoring system consists of two major parts: hardware + It is composed of two major parts: software

Near-infrared detection probe: built-in light source, optical filter assembly, photodetector, temperature sensor;IP65 Industrial dustproof and waterproof housing; optional purge dustproof device, suitable for high-dust working conditions; split design, probe separated from controller, remote installation possible in high-temperature sites.

Controller host: touch screen display, real-time display of moisture and temperature; built-in material model library, supports multi-recipe switching; local storage of historical data.

Signal communication module: standard 4-20mA Analog quantity,RS485 Modbus; optional Profinet、TCP/IP Ethernet, connect to DCS/PLC/ Host computer.

Supporting installation components: mounting bracket, adjustable base, light shield, air purge assembly, cables.

Host computer software (optional): data storage, report export, trend curves, alarm records, remote viewing, meeting factory audit quality traceability requirements.

4. Typical Installation Application Scenarios

Belt conveyor: probe installed above the belt, material thickness≥10~15mm, vertically aligned with the material flow; the most commonly used scenario, feed, grain, wood chips, mineral powder.

Chute / Discharge port: installed at the dryer discharge chute, monitors the drying endpoint, and links with the drying heat source for adjustment.

Screw conveyor: pipeline window installation, suitable for enclosed powder conveying (lithium battery powder, chemical powder).

Roller pressing / Roll material production line: paper, non-woven fabric, film, using transmission-type near-infrared probe.

Installation distance: conventional 200–350mm, fine-tuned according to material model; materials cannot have large voids, ensuring continuous and stable material layer.

Industrial online near-infrared moisture meter, 4-20mA/RS485 signal interfacing with PLC

5. Core Technical Parameters (General Version, can be modified as needed)

Measurement Range:0.1%～95%(Customized according to material calibration model)

Measurement accuracy:±0.1%～±0.3%(Depending on material working conditions)

Response speed: millisecond level, real-time update

Probe protection:IP65, dustproof and waterproof

Power supply:DC24V / AC220V Optional

Ambient temperature:0~55℃; air cooling optional for high-temperature working conditions/ Water-cooled probe

Output signal:4-20mA、RS485 Modbus, Ethernet optional

Calibration method: laboratory sample modeling, on-site calibration with a small number of samples, supports multi-material model switching

Functions: upper and lower limit alarms, automatic data recording, temperature compensation, color difference / Particle interference algorithm compensation

6. Core Advantages of the Solution

Real-time online, no lag:7×24 hours of continuous monitoring, no longer waiting for laboratory test results, timely detection of moisture fluctuations.

Non-contact non-destructive testing: the probe does not contact the material, no wear, no contamination of the material, powder, granules, and sheet materials can all be measured.

Reduce production costs: reduce oven testing consumables and testing labor; precisely control drying, avoid excessive drying and waste of heat energy, and reduce batch scrapping due to excessive moisture.

Process closed-loop control: moisture signal connected to PLC, automatically adjust hot air and feed speed, realizing unmanned water control on the production line.

Anti-interference industrial design: built-in temperature compensation algorithm, multi-spectral reference bands, reducing the impact of material color difference and particle size; optional air purge to prevent dust from contaminating the optical window.

Complete and traceable data: automatically records moisture trends and alarm records, exports reports, meeting ISO, factory audit, quality audit requirements.

Friendly to new and old production line renovation: simple installation, small renovation workload, one controller can mount multiple probes, multi-point synchronous monitoring.

7. Applicable Industries and Materials

Feed industry: feed pellets, powder, bran

Grain processing: flour, starch, grains

Paper: pulp, paperboard, base paper

Wood and building materials: wood chips, wood powder, density board

Chemical: plastic pellets, various chemical powders, fertilizer granules

New energy: lithium battery positive and negative electrode powder

Tobacco: cut tobacco, tobacco leaf redrying

Medicine: traditional Chinese medicine granules, medicinal powder

Food: white sugar, milk powder, filling

Coal / Metallurgy: mineral powder, sinter mixture

8. Implementation Process (Project Landing Steps)

On-site working condition assessment: confirm production line type, material type, moisture range, dust / Temperature environment, installation location.

Sample modeling and calibration: collect material samples, establish a moisture prediction model in the laboratory.

Equipment production customization: probe selection, communication protocol confirmation, supporting brackets and purge accessories.

On-site installation and commissioning: fix the probe, optical path calibration, connect to the central control PLC。

On-site calibration verification: on-site sampling and comparison with oven data, optimize the model.

Training delivery: operation training, model backup, maintenance manual delivery.

After-sales operation and maintenance: regular return visits, model maintenance, remote fault support.

9. Operation and Maintenance Instructions

Daily maintenance: regularly purge the optical window, clean accumulated dust; check the fixed bracket and cables.

Model maintenance: when the material formula changes significantly, re-sample and calibrate the model; under normal working conditions, the model remains stable for a long time.

Wear parts: light source checked and replaced regularly, other components require low maintenance.