The T4000 multi electronic safety interlock system from Sick offers users a host of features that make it suitable for a wide range of sensing applications. With its EN954-1 Category 4 certification, it is particularly suitable for high-hazard environments.
Features offered by the T4000 include a long switching distances (15mm maximum), up to four RFID (radio frequency identification) sensors can be connected to a single evaluation unit, and high immunity to impacts and vibrations.
Applications include the protection of access doors to robot cells, or for protective barriers alongside production lines. Movable covers on machines, such as protective hoods, can also be monitored to prevent unsafe access.
The T4000 multi now has separate door signalling outputs so that each connected sensor can be assigned to a particular door.
The reading head of the T4000 multi is mounted to the fixed part of a guard assembly and connected to the evaluation unit by a cable that is available in two versions for the simultaneous connection of two or four sensors. The reading head uses induction to generate the energy required for the transmission of the transponder code.
The actuator (transponder) is mounted on the moveable part of the assembly, such as an access door, so it is located a safe switching distance from the reading head during machine operation.
While the machine is operating – with the safety device closed – the bit pattern of the code is continuously compared with the stored code. If the codes match, the safe relay outputs and the separate semiconductor outputs for each door are released and the machinery can start. If the safety device is opened, this is detected by the interruption of the data communication, and machine operation is immediately halted. The same occurs if the power supply to the T4000 is interrupted or if the actuator is damaged.
In the case of damage, there is no need to replace the entire system (as is the case for mechanical interlocks), just the actuator, because the evaluation device can learn any number of codes.
The sensor’s large response range offsets tolerances between the door and the protective barrier – thereby reliably preventing false alarms.
In harsh environments the switches are characterised by their robustness and their insensitivity to dirt and contamination.
The same applies for food processing plants that are not only highly contaminating during operation, but also require regular intensive cleaning.
For more information, visit www.sick.de
