Measuring current in a fully-built vehicle – either as part of the vehicle design program or as an after-market operation – can be difficult. There are some good reasons for doing so, however. Here are some answers to frequently-asked questions about in-vehicle current measurements.
Why is vehicle current measurement important?
Measuring the current to one or a small number of ECUs is a useful technique that you can use to identify system issues. ECUs can fail for a number of reasons such as software glitches, hardware failures, load variations, cold weather conditions and mechanical wear, and currents that are much higher or lower than normal can help you troubleshoot and isolate the problem.
What current levels do I need to measure?
There is a very wide range of currents in a modern vehicle, ranging from microamps to hundreds of amps. The instruments you use to make in-vehicle current measurements should cover as much of this range as possible.
How can I measure current without cutting wires?
Cutting cables to make in-vehicle current measurements can be expensive and is likely to introduce reliability issues, a system that allows you to avoid cable modification is the best solution. We offer a current-measurement solution that we call “in-fuse measurement.”
What is “in-fuse measurement?”
In-fuse measurement is a hardware solution that replaces a vehicle fuse, such as a mini-fuse, ATO or MAXI fuse, with a device that can make accurate measurements in the space normally taken by the fuse. Images of several in-fuse measurement devices are shown below.
These devices plug into a fuse box in place of a fuse and communicate current and voltage values via the CAN bus. In-fuse measurement devices offer the following advantages and benefits:
- Measures the entire current flowing in a fuse branch, from microamps to more than 100 A.
- Fits in standard fuse holder, eliminating the need to modify cable harnesses.
- Is equipped with replaceable fuse that provides circuit protection.
- Allows users to correlate current measurements with system events.
- Can be programmed using Simulink/Stateflow, allowing them to be part of an automatic test system.
- Allows users to develop better use case scenarios for more effective system/regression tests using hardware-in-the-loop (HIL) test systems.
- Reduces test time and cost.
- Helps improve ECU and network reliability reducing the number of costly recalls.
For more information on our in-fuse current measurement solutions, please contact us by emailing info@spesdev.com or phone 734-646-3580.
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