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14.8.2023
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LAMBDA controller
type LCP90
designed for LAMBDA sensor
LSU4.9 & LSU4.2
1/12
© IMFsoft, ltd.
www.imfsoft.com
Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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Brief description
The product LAMBDA controller type LCP90 works with a wideband Lambda sensor type
LSU 4.9 and LSU 4.2 (replacement LSM 11) with extended function for PID mixture regulation
using a Stepper motor control. The product is suitable for measuring and regulation the
lambda value, the ratio of AFR and O2 in combustion engine cogeneration units, boilers
burning gas or biomass or other applications.
LAMBDA controller is based on circuit BOSCH CJ125 which serves basic function of
oxygen sensor along with supporting microprocessor for filtering and control. Microprocessor
also provides PID lambda regulation by Stepper motor control, Analog output – AO,
diagnostic interface USB and CANbus in protocol SAE J1939 or CANopen.
Lambda heater is controlled by PID regulator and the resistance of measuring cell (Nerns
Cell) with auto-off option according to engine speed received from CANbus / J1939.
LAMBDA controller processes and visualizes data about Lambda mixture – , Oxygen –
O2, Ratio – A/F, Sensor temperature – T [°C], Supply voltage – U[V], Analog output – AO
[V/mA] Actual step of stepper motor [-] and Engine speed – RPM (from CANbus / J1939).
Main Features
Supply voltage range 7 to 36 V (12V/24V)
Consumption 15 W (Lambda heater and Stepper motor)
Operation temperature -40 to 85 °C
Support for Lambda sensor type: LSU 4.9 and LSU 4.2 (replacement LSM 11)
Used BOSCH CJ125 circuit and microprocessor support
Visualization: Lambda – .......................... 0.7 to 12.5 (± 0.1 %)
Oxygen – O2 ...................... -7.5 to 20% (± 0.1 %)
Ratio – A/F .......................... Gasoline, Diesel, Methanol, Ethanol
E85, LPG, CNG, Hydrogen
Temperature – T [°C] …....... -40 to 1050°C (± 3°C)
Supply voltage – U [V] …...... 7 to 50V (± 0.5V)
Analog output – AO [V/mA] .. 0 – 5 V, 0 – 10 V (± 0.1 %)
0 – 20 mA, 4 – 20 mA (± 0.1 %)
Digital Input DI1/DI2 ............. 0 or 12/24 V
Engine hours ........................ [h:m:s]
Actual step ............................ 0 to 65000 steps
PID mixture regulation by Stepper motor control (microstep 1/2, 1/8 or 1/32)
Power source 11V inside for LAMBDA heating and Stepper motor supply
CANbus support at protocol SAE J1939 or CANopen (250kbps)
Supported connection or integration with ECU MASTER
Galvanically isolated USB – USB protection against earth fault and EMC disturbances
PC application – configuration and visualization measured values
Measuring the supply voltage
No Calibration required
Installation standard – DIN rail 35mm
Protection class – IP20
Dimensions 118x101x23mm
2/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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LAMBDA controller – signal description
MARKING MEANING RANGE, ACTIVE LEVEL
+V Power supply 7 to 36 V (12V/24V)
G Ground supply 0V
AOUT+ Stepper motor – Signal A+ Power 11V / 1A, µ-step 1/2, 1/8 or 1/32
AOUT- Stepper motor – Signal A- Power 11V / 1A, µ-step 1/2, 1/8 or 1/32
BOUT+ Stepper motor – Signal B+ Power 11V / 1A, µ-step 1/2, 1/8 or 1/32
BOUT- Stepper motor – Signal B- Power 11V / 1A, µ-step 1/2, 1/8 or 1/32
DI1
Digital input signal 0 or 12/24 V (need active signal)
DI2
AO Analog Output 0–5 V, 0–10V, 0–20 mA, 4–20 mA
CAN H SAE J1939 / CANopen
CAN bus
CAN L 250kbps
LSU 4.9 (LSU 4.2)
IP (red) Lambda LSU - pin 1 (6*) IP/APE - pump current shunt input
VM (yellow) Lambda LSU - pin 2 (5*) VM/IPN - virtual ground output
HEAT- (white) Lambda LSU - pin 3 (4*) Uh-/H- - heating +
HEAT+ (grey) Lambda LSU - pin 4 (3*) Uh+/H - heating +
IA (green) Lambda LSU - pin 5 (2*) IA/RT - pump current control output
UN (black) Lambda LSU - pin 6 (1*) UN/RE - inverting input of pump
* Index of pins depends on Lambda sensor type
LED SIGNAL MODE DESCRIPTION
Run Measuring and heating function of the probe is in operation
Sleep Operation stopped - Heating switched off (CAN-BUS only)
Fault LAMBDA probe failure (Worn out - must be replaced) 3/12
www.imfsoft.com
Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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LAMBDA controller – wiring scheme
4/12
www.imfsoft.com
Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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Application LAMBDA control – visualization software
Visualization is done from application LAMBDA control run on your PC. The application works
under Windows XP, WIN7, WIN10 or other. Installation requires 4MB of free space at your
hard disc.
To connect lambda to PC is used USB interface. Driver for USB is included on the installation
CD.
Visualized information
Lambda –
Oxygen – O2
Ratio – A/F
Temperature – T [°C]
Supply voltage – U [V]
Analog output – AO [V]
Engine hours [h:m:s]
Revolutions [RPM]
Actual stepper motor possition [-]
Run the visualization
5/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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LAMBDA control application – personalization
The visualization application allows you to import a LOGO.BMP image with dimensions of
375x310 (WxH) pixels, which will replace the speed indicator. The appearance of the
application will thus approach the solution of your technology.
6/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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Table – AFR – Fuels
Gasoline, Diesel, Methanol, Ethanol, E85, Propane (LPG), Methane (CNG), Hydrogen
7/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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Table – Engine AFR – Power / Emissions / Economy
Table – Boilers O2 – Power / Emissions / Efficiency
8/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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LAMBDA – Analog Output – AO
LAMBDA controller is able to generate an analogue output depending on measurement of the
immediate LAMBDA values. Output curve can be adjusted to five different waveforms, any
further are possible to add upon your special requirement. The exact value of each voltage
curves are displayed in a separate file LAMBDA_AnalogOUT (1002-0022-14).
LAMBDA sensor LSU 4.9 – BOSCH 0 281 004 148 or BOSCH 0 258 017 025
9/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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Assembly drawings
10/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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Frequently Asked Questions - FAQ
How to connect to LAMBDA controller via USB?
The LAMBDA controller can be connected to a PC via a USB cable, where a virtual
serial port is created in the PC after connection, where information about port creation
and port number can be found in the device manager.
There may also be a problem with the USB driver, where the current version can be
downloaded here: https://ftdichip.com/drivers/vcp-drivers/
Why measurement of LAMBDA show incorrect value?
1) Is this a new application or has it already been used?
The oxygen sensor life-time is limited to 8,000 hours, so it may be worn.
Did you tried to replace the LAMBDA probe with a new one?
It can be damaged earlier due to dirt, corrosion or moisture
The red LED on the controller lights up if detect fault.
2) Is the cable for connecting the LAMBDA probe fine ?
Did you use our LEC 1.5m, 3.0m or 5.0m extension cable?
You have checked the correct wiring and they are not too long?
The maximum extension cable length is 5 m.
3) Do you have the LAMBDA probe installed in the correct position?
It should be installed at an angle upside down so that water and moisture
can flow out of it. Please look at the picture from the previous page
4) Didn't you cut the connector on the LAMBDA probe?
The connector at the LAMBDA probe that contains the calibration resistor.
After cutting, 6th wire will be missing and LAMBDA measurement will
show incorrect values.
5) Do you have a strong power supply with + 12V or 24V supply voltage?
The consumption of the lambda probe is 10W, so the source with a reserve
should be at least 20W.
The level of supply voltage is displayed in the LAMBDA control application.
6) Did you configure the LAMBDA controller?
It is necessary to set the controller and write it in the memory for the
required function eg curve type O2 4.0 and output 4-20mA.
How to protect LAMBDA signal against interference?
We recommend the use of Twisted pair wires for connecting the LAMBDA probe
to the Controller, for power supply and output signal or CAN-BUS.
It is necessary to count 10W for the power supply conductor, therefore the conductors
should have a cross-section of at least about 0.75 to 1.5 mm2 with respect to the
distance.
11/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
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How to set stepper motor mixture control ?
The setting is individual, but the main key is to know and set the number of
steps for full opening and to start the engine.
12/12
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Document: 1002-0028-15 LAMBDA controller - LCP90 info@imfsoft.com
