Electronic Throttle typically uses the Accelerator Position Sensor (APS) to determine the drivers requested throttle opening. However, the actual target throttle position can come from a variety of sources depending on what is used on the axis of the EThrottle Target Table. It is most common to have APS (Main) as one axis on the target table.
APS (Main) provides the actual drivers request. APS (Sub) is used as redundancy to verify the validity of APS (Main). APS (Main) and APS (Sub) can be driven either from an external pair of sensors on the drivers throttle control (pedal or lever etc) or can be driven over CAN from an external device. In either case both signals must be correct and calibrated for error checking to work correctly.
Further information regarding fault detection of these signals can be found in the safety section.
Once wired, view the voltage reading of each channel using PCLink and confirm a voltage is present. Move the accelerator pedal to confirm the voltage output is changing during movement.
If using CAN Analog inputs to drive APS (Main) and APS (Sub) both the ECU and external device must have their CAN bus drivers configured correctly. It is beyond the scope of this help to cover CAN configuration of external devices. Contact your Link dealer for further information on configuring the ECUs CAN bus for APS signals.
Note: When using CAN Analog or Math Block inputs the value is taken directly and so must always be in the 0 to 100 range. If a resolution of 0.1% increments is desired over CAN then transmit the signal with a 0-1000 range and use a divider value of 10 when setting up the CAN stream. No extra calibration is required when driving APS signals from CAN or Math Block.
APS Settings:
Allows the user to select the main accelerator position signal source, this includes CAN Analog options.
Most dual APS sensors will have an output voltage that spans the full working range of throttle plate or pedal movement.However, on some applications one sensor will span the full working plate range while the other will ONLY read up to about 70%. APS(Main) MUST be assigned to the signal that changes over the full working range and the other signal assigned to APS (Sub). Under no conditions should the orientation and these two signals be swapped.
Allows the user to select the secondary accelerator position signal source, this includes CAN Analog options.
After correctly setting up analog inputs they must be calibrated such that 0% is no driver demand and 100% is full power demand.
This can be done in one of two ways:
·Automated calibration - EThrottle 1 Mode must be in 'Setup Mode', go to Electronic Throttle->Accelerator Position Sensor, select APS Calibration and follow the on screen instructions.
·Manual calibration - Manually enter the open and closed sensor signal voltages for the APS (Main) Closed, APS (Main) Open, APS (Sub) Closed and APS (Sub) Open settings. APS (Sub) 100% also needs to be set appropriately.
The sensor pin voltages can be seen in the Analog Inputs tab of the Runtime Values Window (press F12).
Some Accelerator Position sensors have one signal that stops changing before full travel is reached, these sensors are most often found on Toyota and Lexus engines. For non linear sensors the APS (sub) 100% value must be set to the APS (Main) value at which the APS (Sub) number stops increasing at (typically around 60-70%).
For linear sensors, which the majority of Accelerator Position Sensors are, this number must be set to 100%.
APS (Main) Closed, APS (Main) Open, APS (Sub) Closed & APS (Sub) Open
These settings have no effect if APS (Main) Source is set to a CAN Analog or Math Block.
These values are automatically set when using the APS Calibration function.
·APS (Main) Closed - The voltage of the APS (Main) input when the throttle pedal has no force on it.
·APS (Main) Open - The voltage of the APS (Main) input when the throttle pedal is in it's maximum throttle position.
·APS (Sub) Closed - The voltage of the APS (Sub) input when the throttle pedal has no force on it.
·APS (Sub) Open - The voltage of the APS (Sub) input when the throttle pedal is in it's maximum throttle position.
Analog Input Fault Settings
Note this only applies to analog inputs (not CAN Analog or Math Block inputs), CAN Analogs will fault if the CAN string containing the CAN analog hasn't been received for a certain amount of time.
After APS (Main) and APS (Sub) inputs have been wired and tested on their respective analog input channels, fault values must be setup for these channels. A low voltage and high voltage fault setting is provided for each channel, these settings specify the voltage ranges used to determine a possible fault condition on the analog channel. Typical values for these settings are:
·Analog X Error Low = 0.1 V
·Analog X Error High = 4.9 V
Note that these settings can have values closer to the working range of the position sensor if required. E.g. if the sensor outputs 1.0 to 4.2 V, Error Low could be up to 0.8V and Error High could be down to 4.4 V.