UEGO (Universal Exhaust Gas Oxygen) Sensor

The UEGO Sensor I/O task is a uego sensor simulator by Concurrent, applicable to the CP-UEGO-4 card. The card has 4 channels. You can also simulate applying faults to the UN, VM, IP, and IA/RL lines.

I/O Card Model Numbers

CP-UEGO-4

I/O Driver Model Number

WC-UEGO

I/O Module License

ICS-SWB-1283

Channel Mapping

For each channel, you can map:

Lambda - Calculated stoichiometric ratio of the air / fuel mixture in the exhaust gases.
Cell Temp (°C) - Calculated cell temperature of the probe, specified in degree Celsius.
Heater Input - Duty cycle of the power applied to the heater, specified in the [0 100] range.
Faults - You can apply the following faults to the UN (Nernst cell voltage), VM (virtual ground), IP (primary pumping current), and IA/RL (trim resistor) lines. Only one fault can be active at a given frame.
- Open: When the associated DO variable is high, the relevant line is open.
- Ground: When the associated DO variable is high, the relevant line is grounded.
- Vbat: When the associated DO variable is high, the relevant line is connected to Vbat.

Probe Properties:

The Probe Properties pane allows you to configure each channel of the UEGO sensor.

Channel: Select the channel to configure.
Narrow band: Specify whether the card should be used in:
- Wide band mode - Cell voltage is equal to the product of cell resistance and Ip, expressed in mA. The following curve definitions are required in this mode:
  - Cell λ/Ip
    - Curve definition: Specify mechanism used to define the λ/Ip curve in the editor below.
      - Table - Enter the (λ, Ip) value pairs, one per line, using a space delimiter.
      - Polynomials - Enter the curve polynomials, one per line, using the following convention (polynomial order must be four or less):
        
        [λ_min λ_max] a₀ a₁ a₂ a₃ a₄
        
        Such that the curve is represented by: a₄λ⁴ + a₃λ³ +a₂λ² +a₁λ¹ +a₀
        
        For a piecewise function, enter one line per polynomial. For example, suppose the function is represented by c₁ and c₂. You must enter:
        
        [λ_min,c₁ λ_max,c₁] a_0,c₁ a_1,c₁ a_2,c₁ a_3,c₁ a_4,c₁
        
        [λ_min,c₂ λ_max,c₂] a_0,c₂ a_1,c₂ a_2,c₂ a_3,c₂ a_4,c₂
        
        To ensure contiguity, λ_max,c₁ must equal λ_min,c₂.
    - Offset voltage: Voltage offset. This is the default cell voltage when λ == 1.
    - Cell resistance: Cell resistance used to calculate cell voltage.
  - Cell °C/R
    This curve defines the relationship between the probe resistance and its temperature. To define this curve, use the curve definition mechanism described for the Cell λ/Ip curve.
- Narrow band mode - Specify the voltages for rich,normal and lean mixtures.
  - Rich : if λ <= 0.99
  - Lean : if λ >= 1.01
  - Normal : otherwise

Checking Output Values

This I/O task uses λ and cell temperature to calculate the Ip, cell voltage, and cell resistance values on a per-channel basis. These values are written to the UEGO card. To validate these calculated outputs via the driver interface:

Set Debug to 255 for uegoin and uegoout in the I/O Tasks tab in the Control Centre.
Examine and run the uego test in the Hardware-Tests/UEGO project.
While the test is running, for a given channel, set the λ and cell temperature values using the Real-Time Viewer.
Use the Cell λ/Ip curve to determine the expected Ip value for the specified λ value. Similarly, use the Cell °/R curve to determine the cell resistance value for the specified cell temperature. Use the mouse to hover over the graph in each of the curve tabs to see the expected value for the given X axis quantity.
1. Cell resistance: At a terminal on the real-time host, execute
```
/usr/local/CCRT/drivers/ccuruego/test/lib/ccuruego_tst_lib
         
```
  A menu with many options appears. Select option 33 (DIGITAL POTENTIOMETER MENU). A submenu appears. Select 3 (Digital Potentiometer Get Resistance). The output displays the resistance on a per-channel basis in the Ohms column.
2. Cell voltage: At a terminal on the real-time host, execute
```
/usr/local/CCRT/drivers/ccuruego/test/lib/ccuruego_tst_lib
         
```
  A menu with many options appears. Select option 32 (DAC CONTROL MENU). A submenu appears. Select 3 (DAC Read Channels). The output displays the DAC Offset and the DAC Reference values on a per-channel basis.
3. Ip: Divide the cell voltage (DAC Reference value) by the cell resistance to obtain the primary pumping current. This value can also be confirmed in the debug output of the I/O task in the cfgsrv.log tab of the Control Center.

Note: There may be quantization errors that lead to some negligible variance between the values displayed in the Control Center I/O mappings pane and/or cfgsrv.log tab and what the driver returns.

Synchronous I/O Tasks