Written by Mike Lepkowski & Ray Hyder
Option controls – Customizing OpenECU hardware for specific system requirements
Most systems require specific interfaces between controllers and sensors or actuators. While OpenECU has been designed to support a variety of sensors and actuators it can support an even larger variety of sensors through small changes to hardware in the ECU itself. Pi Innovo calls this modification an option control which uses one of our off-the-shelf OpenECU modules.
Option controls are best for customers developing prototype and low volume production systems where an existing OpenECU product meets most system needs but details of the interface between OpenECU and sensors/actuators require hardware changes. The most common option controls are changes to analog input circuits which allow OpenECU to exactly match the sensor interface as the sensor’s manufacturer requires.
Pi Innovo will work with you to define your requirements and come up with the best modifications to suit your application.
Which option control is needed for your application
Pi Innovo will work with you using our “Options and Variants” document that describes the default population of each pin on the module and the range of configurability that is available with an option control. Pi Innovo engineers will assess the compatibility of the customer’s I/O requirements with the default population of OpenECU and identify any areas where the default hardware configuration isn’t quite right for the system. Once those gaps are identified, Pi Innovo creates a custom option control which will configure OpenECU to be a perfect fit for the customer’s system needs/interfaces. Some examples of common changes in option controls:
- Changing analog input pull resistance
- Add/remove CAN termination
- Change the low pass filter frequency of a digital input
- Add/remove a freewheeling diode on a low side output
- Change the pull-up source voltage on analog and/or digital inputs
More advanced option controls
For customers with more specific needs, Pi Innovo may be able to add totally new functionality to an existing OpenECU. Some examples of specific functions added for past option controls:
- Piezoelectric pressure sensors were added to M670
- BLDC motor control was added to M250
- A 6-axis IMU was added to M670
- Current measurement was added to low side outputs on M220
- 4x H-bridge outputs were added to M670
Option control example
Recently on the M560, Pi Innovo worked with a customer to define their needs. The identified change was fairly small and made all the difference in making the M560 a perfect fit for the customer’s application. A digital input that was ranged for battery level 0-16V needed to be used as a 0-5V input. A change to the filter frequency was also identified as necessary to be compatible with the expected frequency of the sensor. Originally, the input had scaling for battery level inputs and was filtered for low-frequency inputs (25Hz). The scaling was changed to work with 0-5V PWM input and the filter frequency modified to work with 500Hz. This option control is now purchasable by the customer as the M560-00F.
What are you working on?
If you are not able to find an off-the-self controller solution to meet all your system’s needs Pi Innovo may be able to help with an option control for OpenECU.