Thursday, 23 January 2020
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Lift light grid made in Germany

DUOmetric AG has developed an affordable LT40 light grid for use in lifts, especially to meet the requirements of the EN81-20 and 81-70 standards.

(Photo: © auris -

"Like all of our light grids, the LT40 is also completely ‘Made in Germany’," emphasised the company, which has been specialised in light grid systems for all kinds of applications for 20 years.

To guarantee secure recognition of objects greater than 50 mm, the door area is monitored with parallel beams every 46 mm. As a result, this requirement from EN81-20 is met continuously up to 1,600 mm in the entire closing area without having to pay attention to the distance of the transmitter from the receiver strip. DUOmetric dispensed with the lower cost diagonal beams in order to simplify lift planning.

Closing cycle with reduced force

The LT40 is intended to provide all options for the control device. Permanently-interrupted individual beams are faded out by the system; this is indicated in the warning output. A closing cycle is possible immediately with reduced force, since the "monitoring area free" information of the remaining beams is preserved.

As a result, the timeout period at the floor is not extended to the timeout of the control mechanism and convenient recognition of obstacles in the closing area is preserved. For this purpose, only the warning output in the combinatorial analysis of the control system has to be considered. In the range beyond 1,600 mm, the warning output only reacts in the event of defects to ensure that availability is not reduced unnecessarily.

Shut down by means of an input signal

The transmitter strip can be shut down by means of an input signal. The control mechanism can trigger a switching process in a controlled manner in this way and for example realise a start-up test or simply help to save electricity.

For easy installation, the tried-and-tested lift mechanism with catches at the bottom and threaded stud bolts at the top is used. This ensures backward compatibility with previous models and replacement or upgrades are consequently possible at any time without any problems.

Two push-pull switching outputs

The LT40 is delivered ex works fully-configured. No manual adjustment to the operating range is necessary at start-up, since the sensitivity of the light grid is adjusted automatically.

The LT40 has two push-pull switching outputs. Apart from the warning output (active if the functions are in order), there is the signal output that can be converted by polarity reversal of the power supply at the receiver between light- and dark-switching.

According to DUOmetric, the LT40 is an efficient, affordable solution for all standard car sizes, which can also be individually customised and thus provides maximum flexibility.

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