Ultrasonic Obstacle Detection
FAQs, Tech Tips and Diagnostic Workflows
FAQ’s
What is the black wire for on the BS-4000W and FS-4000W?
The black wire is a trigger output which activates when the system detects an object. For example, to activate a warning alarm. The output is a switched ground with a limit of 250mA and must be connected via a diode protected relay to prevent irreversible damage to the system.
Why is the system permanently detecting?
The first thing to do is to cover the face of the sensor with light pressure (using a finger or thumb) if the detection stops it implies the sensor is detecting an object.
- Check that the sensor is mounted the correct way around, each sensor is marked on the top with the word “UP” it is important the sensor is not mounted upside down.
- Check the sensor is mounted at the correct angle there is a Tech Tips here to assist with this. If the sensor is mounted too low or the mounting sleeve angle is too small the system can suffer from detecting the ground. Try to use a larger angled sleeve or mount the sensor up higher.
- If there is a fixed object being detected for example a tow ball, try to initialise Environmental Learning Mode (ELM) see FAQ below and by checking out the corresponding Tech Tips here.
How can the system ignore fixed objects, like a tow ball, from being detecting?
It is always best practice to mount sensors where they will not detect parts of the vehicle but if this is unavoidable then the system has a feature called Environmental learning mode (ELM). ELM can be used to ignore limited objects that do not move relative to the sensors.
To activate ELM the system power needs to be turned on/off/on 4 times, please allow the system to power up and detect before switching the power back off each time (about 6 seconds between cycles). When the system is switched back on for the 5th time it should not detect the object.
Please be sure to test the detection performance of the system after applying ELM.
Why does the system beep when it is switched on?
All UDS systems have a self-diagnostic feature that checks for faulty sensors when the system powers up. The system will give a single beep for each sensor that is not working. So, one beep identifies one faulty sensor, two beeps identify two faulty sensors, etc…
When do I need to install a Relay to the trigger (switch to ground) wire on my ECU and if so, how?
A diode protected relay is a requirement when using the (SWITCHED GROUND) trigger wire from the ECU.
This is an Optional connection used to operate auxiliary devices such as beacons or external alarms through a relay by providing a switched ground.
- When is a diode protected relay needed?
- Why is a diode protected relay needed?
- How to wire a diode protected relay correctly in your system?
