Product category:
Safety relays, interlocks, control systems, electrical components
News Release from: SICK (UK) | Subject: Multi electronic safety interlock system
Edited by the Manufacturingtalk Editorial
Team on 07 November 2005
Multi RFID safety system copes with
hazards
Multi electronic safety interlock system features long switching distances (up to 15mm), up to four RFID sensors and high immunity to impacts and vibrations.
Multi electronic safety interlock system features long switching distances (up to 15mm), up to four RFID sensors and high immunity to impacts and vibrations The T 4000 multi electronic safety interlock system from SICK (UK offers users a host of features that make it suitable for a multitude of different sensing applications
This article was originally published on Manufacturingtalk on 12 Sep 2008 at 8.00am (UK)
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With its EN 954-1 Category 4 certification, it is particularly suitable for extremely hazardous environments.
Features on offer from the T 4000 include a long switching distances (up to 15mm), up to four RFID sensors connectable to a single evaluation unit and high immunity to impacts and vibrations.
While the applications include the protection of access doors to robot cells or for protective barriers along production and assembly lines, such as those seen in the automotive industry.
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One customer request that is now available from the T 4000 multi is separate door signalling outputs so that each connected sensor can be individually assigned to a particular door and evaluated on this basis.
The reading head of the T 4000 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 actuator - a transponder - is mounted on the moveable part of the assembly, such as an access door, in such a way that it is located at a safe switching distance of 15mm from the reading head during machine operation.
The reading head using induction to generate the energy required for the transmission of the transponder code.
The entire monitoring process takes place via radio frequency identification (RFID).
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 semi-conductor 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 outcome occurs if the power supply to the T 4000 is interrupted or if the actuator is damaged.
In the case of equipment damage, there is no need to replace the entire system (as is the case for mechanical interlocks), only the actuator, because the evaluation device can learn any number of codes.
As only the last code that was learnt is valid, and multiple teach-in of the same actuator to the same evaluation device is impossible, the system is highly tamperproof.
The sensor's large response range offsets tolerances between the door and the protective barrier - reliably preventing false alarms.
Its immunity to impact and vibration is particularly important when safeguarding elevators, palletisers and depalletisers, or machines for securing loads.
Movable covers on machines, such as protective hoods, can also be monitored to prevent unsafe access.
In harsh environments, such as those seen in paper mills, 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.
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