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Enabling better global research outcomes in soil, plant & environmental monitoring.

ES-642 Remote Dust Monitor

The ES-642 Remote Dust Monitor is an industrial air quality sensor designed to provide real time particle concentration measurements in both indoor and outdoor environments.

The ES-642 has flexible serial ports and analog outputs to support various data collection systems. The serial ports support MODBUS and simple ASCII commands via RS-232 or RS-485. Analog outputs include both 0-10 volts and 4-20 mA.


  • Rugged Weatherproof Enclosure: For reliable continuous outdoor operation
  • Purge Air System: Keeps optical components clean so the ES-642 can operate in adverse environments without performance degradation.
  • Automatic Zero Calibration: Reduces long term measurement drift by automatically adjusting the zero value each hour. The interval is user settable from 1 to 999 minutes.
  • Controlled Inlet Heater: Active inlet humidity control to reduce measurement errors. The ES-642 monitors inlet humidity levels and regulates heater power to maintain lower humidity levels.
  • Front Panel LCD Display: Provides information about particulate concentration, flow rate and instrument status.
  • Flexible Mounting Hardware: Mounting bracket included for wall or 2” vertical mast mounting. Optional hardware available for vertical mast diameters up to 4.7 inches (120 mm).


  • Building Automation
  • Military Applications
  • Environmental Clean-Up Sites
  • Air Pollution Level Monitoring
  • Dust Level Warning Systems

The unit is supplied in a rugged weatherproof enclosure. It includes an LCD display to provide information about particulate concentration, flow rate, instrument status and power. The electronics and optical system are protected from moisture by a built in intake heater that is humidity level controlled. The heater power is regulated to maintain a minimum humidity level. Additional features include a purge air system and an automatic zero calibration routine.

The sensor can be wall mounted or installed on a vertical mast up to 3 inch in diameter. The ES-642 is supplied with a 10 ft cable and connector for power (15 to 40 VDC) and signal output.
The ES-642 measures particulate concentration using a highly sensitive forward scatter laser nephelometer, having a measurement range of 0 to 100 mg/cubic meter or 0 to 100,000 ug/cubic meter. Optional sharp-cut cyclones are used to set the measurement level of the ES-642. As supplied it provides particulate monitoring for TSP, with the addition of the sharp-cut cyclone it can be set for particulate smaller than PM10 or smaller than PM2.5, or PM1. The accuracy of the instrument is ±5% based on a traceable PSL 0.6 micron reference standard.

Measurement Principle: Particulate concentration by forward light scatter laser Nephelometer
Available Cut Points: TSP Inlet Standard. PM10, PM2.5, and PM1 sharp-cut cyclone inlets available.
Measurement Range: 0 to 100 mg/m3 (0 to 100,000 mg/m3)
Measurement Sensitivity: .001 mg/m3.
Nephelometer Accuracy: ± 5% traceable standard with 0.6um PSL.
Particle Size Sensitivity: 0.1 to 100 micron.
Display: 2 X 16 backlit LCD. Provides concentration, flow and status information.
Zero Calibration: Automatic Zero Calibration every hour or as programmed from 1 to 999 minutes.
Flow Rate: 2.0 liters/minute ± 0.1 lpm.
Input Voltage: 11 – 40 VDC
Power Consumption: 12 VDC = 300 mA (heater off), 1.2 A (heater on)
24 VDC = 140 mA (heater off), 0.6 A (heater on)
Analog Output: 4-20 mA and 0 – 10 VDC.
Serial Ports: RS-232 and RS-485
Serial Protocols: ASCII Text data format and MODBUS RTU.
Alarm Output: Normally open and normally closed relay 30 VDC @ 1A maximum.
Operating Temperature: -10 to +50°C. (Ambient Temperature Sensor Range -30 to +50°C).
Barometric Pressure: 600 to 1040 mbar pressure sensor range.
Ambient Humidity Range: 0 to 90% RH, non-condensing.
Intake Moisture Control: Automatic 10 Watt inlet heater module controlled to sample RH set point.
Factory Service Interval: 24 Months typical, under continuous use in normal ambient air.
Mounting Options: Mounting bracket standard (wall or 2” vertical mast). Optional EX-905 tripod.
Unit Weight: 2.7 kg (6.0 lbs.)
Unit Dimensions: 22.9cm high, 17.8cm wide, 10.8cm deep. (9.0” x 7.0” x 4.25”). w/out inlet assy.
48.3cm high, 17.8cm wide, 10.8cm deep. (19.0” x 7.0” x 4.25”). w/ inlet assy.