SafeSense™
The patented SafeSense technology from Gardasoft allows the safe and accurate driving of LED lighting for machine vision applications,this technology enables the performance of LED lighting to be fully optimized whilst ensuring that the lighting can never be overdriven outside of permissible current ratings. Overdriving LEDs allows for more light output to be achieved and SafeSense imposes safe working limits based on the pulse width and duty cycle for LED overdriving, thus providing full protection. In constant mode, the maximum output current allowed would be the maximum rating defined by SafeSense. SafeSense works by using the following techniques:
- Sensing when a light is connected
- Finding the current rating of the light
- Driving the light within safe limits
- Detecting faults
1. Sensing when a light is connected
The operation of the controller is as follows:
- Tries to drive a low current pulse through the light
- Measures the current to see if a light is connected
- If 10 pulses are successful, detection is complete
2. Finding the current rating of a light
Current rated lights
The current rating is entered by the user. This can be done using the front panel, webpages, configuration program or application program.
Voltage rated lights
If the voltage rating of a light is known, this is simply entered into the configurator and the current rating can be automatically measured. In some configurations, the voltage rating can be determined by the type of connector on the light (12-36V), and the current again will be automatically calculated
2. Finding the current rating of a light
SafeSense™ – vital when overdriving LEDs
The controller will limit the parameters based on the limits in the table below. Customer specified limits can be installed into the controllers at the factory.
| Overdriving | Allowed pulse width | Allowed Duty Cycle |
| Up to 100% | 1S | 100% |
| Up to 200% | 30mS | 15% |
| Up to 300% | 10mS | 10% |
| Up to 500% | 2mS | 5% |
| Up to 1000% | 1mS | 2% |
4. Detecting faults
The current and voltage to the light is continuously monitored, the faults detected are:
| Open circuit | - The light is disconnected |
| Short circuit | - The light has a wiring fault |
| Voltage high | - An LED or wiring failure in the light |
| Current low% | - Too much voltage is required to drive the requested current |
APP936
