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Elevator positioning system USP 30 / 100
Other possible causes of failure
a) Distance sender-receiver
(page 62 - Reference E)
If the receiver is installed in the shaft head you may see a red LED in some cases after the initial
power supply if the cabin is in top position.
Background
When you switch on the USP the receiver will identify the position of the sender. The sender will
activate an ultrasonic signal which will be received by the receiver. If you have a short distance
between sender and receiver, the ultrasonic signal will be transmitted by air and by wire. In this
case sender and receiver cannot synchronise themselves. This effect can be influenced by the
environment.
Relieve
To be on the safe side we recommend a minimum distance of 80 cm between receiver and sen-
der. Please apply the advice given on page 39.
Hint:
This is true in the same sense for installations in the shaft pit.
b) Electromagnetic Compatibility (EMC)
(page 62 - Reference B,E)
As long as the car does not move, both LED’s show a green light. As soon as the car moves,
you see a red light.
Background
The USP receiver comes with a completely protected plastic housing. However, it is a complex
electronic device which may be influenced by strong magnetic fields. If any other unit which
may generate strong fields is installed close to the USP system its function may be influenced.
This could be motors, inverters or choppers.
Relieve
You should care for a sufficient distance between lift components like motors, inverters, chop-
pers to the USP receiver. In some cases a metal sheet with a ground connection between the
components may help.
Hint:
If you care for a sufficient distance between the devices during installation this trouble
will not occur. After installation the grounded metal sheet will help.
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