Laser Particle Monitor
LPM 1 Series

Stauff_Laser Particle Monitor_LPM1

The STAUFF Laser Particle Monitor System LPM 1 is a laser based 4-channel inline particle monitor designed for the continuous monitoring of particle contamination. The LPM 1 provides cumulative particle concentration information at >4 μm(c), >6 μm(c) and >14 μm(c) sizes applicable to the ISO 4406, ISO 11943 and ISO 11171 requirements for optical particle counters. A >21 μm(c) channel is also provided for larger particle concentration information. Machine operators are alerted to changes in particle contamination levels in a machine's fluid by the indications provided from the LPM 1. The contamination level will be shown on the display or can be transmitted via the RS-232 serial port into a personal computer. With the ModBus-serial port the data can be transferred into a computer network or to an external display. The LPT particle transducer is configured via the IR-port on a Palm or Pocket Computer. The LPM 1 system consists of a Laser Particle Transducer LPT and a Laser Interface Module LIM.

Technical Specification

Channel Sizes 4, 6, 14 and 21 μm(c)
(ISO MTD/ISO 11171)
Connections SAE - 4 (7/16-20 UNF)
Light Source Laser Diode Flow Rate 50 to 500 ml/min through the viewing area. All units offer integrated flow rate monitoring with alarms.
Verification Optional certification available Fluid Compatibility Mineral based hydraulic and lubrication oils. Phosphate Esters optional
Sampling Online continuous monitoring Viscosity 32 SUS (2 cSt) minimum
Reproducibility + 0.5 ISO code (ISO 4406) Operating Pressure 20 to 7,250 PSI (1.4 to 500 bar)
Display Optional local display presents ISO codes and alarms Operation Temperature -4 to 140°F (-20 to 60°C) ambient,
-4 to 185°F (-20 to 85°C) fluid
Power Supply 9 to 36 volts DC IP Rating 67
Output RS-232, RS-485, 0 to 5 volts, Modbus, alarm contacts, local display Accessories Included DDE Software, 20 ft. (6m) fiber optic cable, operators manual
Reports Particles/ml, ISO 4406 codes 4, 6, 14 and additional 21 μm(c) (ISO MTD/ISO 11171)



Stauff_Laser Particle Monitor_LPT

Laser Particle Transducer LPT
The LPT Particle transducer contains the sensing device and electronics for detecting the level of contamination

The laser based sensor uses light blocking technology for particle detection whereby particles passing through an optical flow cell block an amount of laser light proportional to the particle size.

The resultant particle concentration data from the LPT are sent to the LIM interface module via a fiber optic cable. The configuration of the LPT has to be done through the IrDA port of any PDA with IRA capabilities.

The LPT Particle transducers have a flow inhibitor downstream of the sensor that restricts and controls fluid flow from variable pressure sources.

The pressure is reduced to near atmospheric for return to the hydraulic reservoir. The inlet pressure ranges from 1.4 to 500 bar (20 to 7250 PSI) in three models are listed below.

The LPT's are available with or without a LED display. The three digit display shows the selected ISO code value or other function parameters.

Available types of LPT

LPT-1 400 to 7250 PSI (28 to 500 bar), without LED-display
LPT-4 400 to 7250 PSI (28 to 500 bar), with LED-display
LPT-7 50 to 1200 PSI (3.4 to 83 bar), without LED-display
LPT-8 50 to 1200 PSI (3.4 to 83 bar), with LED-display
LPT-9 20 to 200 PSI (1.4 to 13.8 bar), without LED-display
LPT-0 20 to 200 PSI (1.4 to 13.8 bar), with LED-display


Stauff_Laser Particle Monitor_LIM-1



Stauff_Laser Particle Monitor_LIM-3



Stauff_Laser Particle Monitor_LIM-4-5

LIM-4 and LIM-5

Interface Module LIM
The LIM interface module converts the raw count data from the LPT for display or use in acquisition, logging or control systems. A terminal emulation program can be used to read the ASCII data string. The LIM interface modules are available in four types to meet a wide variety of applications. The LPT is connected to the LIM via a fiber optic cable with a length up to 50 meters (175 ft.).

The LIM-1 interface module has a DCE configuration (9-pin female) for attachment directly to a computer's RS-232 serial port. Power for the LIM-1 is supplied by the computer serial port.

The LIM-1 receives the raw serial data from the LPT transducer via a fiber optic cable and transmits them directly to the computer.

The LIM-3 receives raw serial data input from the LPT transducer via a fiber optic cable. This data string is analyzed and converted into 0 to +5 VDC analog output voltages proportional to the ISO codes and also into ModBus ASCII device protocol for interface to a PLC or computer via RS-485 and RS-232 serial port.

Special adaptors also allow the integration into an ethernet-computer network.

All signal outputs, as well as the input supply voltage (9 to 36 VDC), are connected to the LIM-3 through a DB-15 connector.

LIM-4 and LIM-5
The LIM-4 and LIM-5 receive the raw serial data input from the LPT transducer via a fiber optic cable. Results are displayed on the front panel 3-digit LED display.

The ISO 4406 code number displayed is categorized in four size channels (>4, >6, >14 and >21 μm(c) ). The ISO number represents the number of particles counts per ml fluid. The user also can select internal information about the transducer (Temperature C, laser mA, Cal V, Node ID status code).

Alarm levels can be programmed for any of the four particle size channels. When set, an alarm indicator will flash if the alarm level is reached. For the LIM-4 the alarm is activated if the measured ISO numbers exceed the set alarm level and for the LIM-5 the alarm is activated if the ISO number falls below the set level.

Alarms on the LIM-4 and LIM-5 may be deactivated by pressing any button. Supply voltage is external and can be from a 9 to 36 VDC source.