In many applications the cable run between a remote sensing- or safety-switch can be vulnerable to damage or vandalism. Typical of these applications is the connection to an anti-trap safety sensor (such as a sensing edge) on the leading end of a sliding gate. When the gate is fully open, the distance from the sensing edge to the gate controller may only be a couple of meters but when the gate is fully closed, that distance may have increased to 30 meters or more. Using coiled cable or employing cable-tensioning systems to cater for this varying length of cable run can still leave the cable vulnerable. Equally it could simply be more convenient to have a wireless connection between a switching device and a control system. For example, the installation could be short-term and does not warrant full-scale permanent installation of the cables.
Up to 6 transmitters can each monitor the state of a different fail-safe switch and pass that information wirelessly to the receiver to give a pass/fail output for the system. Each transmitter monitors an end-of-line resistor in the switch and the receiver can present either a closed contact or an end-of-line resistor as a pass output.
The range of the system is specified as 10 meters but dependent on the surroundings (high buildings, metal walls, etc) a range of over 40m is typical. Performance is better when the transmitters and receivers are mounted vertically and high on the installation.
- Leading edge protection