Locating a defective sensor in system concepts with conventional wiring is quite difficult. Machines usually have to be shut down for long periods while the cause of the fault is located.
In a modern system concept such as the AS-Interface, special integrated circuits lend the sensors a certain degree of “intelligence” and extend their range of functions. These inductive sensors are able to monitor both themselves and their supply cables and exchange data with a higher-level unit such as a PLC.
In practice, inductive sensors are positioned so that the distance between the actuating element and the active surface is about 50 % of the rated operating distance sn. The switch is guaranteed to function correctly within the assured operating distance sa = (0 to 0.81) • sn. If the actuating element is located between sa and the actual operating distance sr, a failure warning display bit (data bit 1) is set so that maladjustments can be detected early before a detection error occurs.
The default value of data bit 1 is “1”, which means “normal state”. If the failure warning display is set, the value of this data bit is “0”. This value remains the same until the inductive sensor is fully damped or the target has approached to a point closer than sa and is then removed again, i.e. sr + hysteresis.
We offer inductive AS-Interface sensors with the following designs:
Cylindrical
Cuboid
Position sensors