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Design and Functions
9.5.4.1.8
Floor Information
In order for LIMAX44 RED to operate the door zone indication, the evaluation unit has to transmit the floor in-
formation to the sensor. In the interval between two telegrams the evaluation unit has time for this. (
9.5.4.1.10 Bus Timing). LIMAX44 RED assigns the received information in relation to the message counter (
9.5.4.1.3) of the message that was just sent.
Table 7: Floor information as a function of the value of message counter
Counter
reading
Content
0
Number of floors
1
Size of door zone (0 … 1020 mm; 1 LSB
≙
4 mm)
2
LSB of the flush position first floor (1 LSB
≙
16 mm)
3
MSB of the flush position first floor (1 LSB
≙
16 mm)
…
…
255
MSB of the flush position 127
th
floor (1 LSB
≙
16 mm)
This data is for the transmission of the floor image, so that LIMAX44 RED can generate the door zone signal as
return motion information. For this purpose, the resolution of 16
mm is sufficient.
If necessary, LIMAX44 RED will update the stored floor image based on the received data. In order to avoid
non-recurring transmission errors having an influence on the floor image, the floor table is only changed when
the information is transmitted a second time, i.e. is confirmed. Depending on the value of the message counter,
it therefore can take up to two seconds before LIMAX44 RED takes over the new floor information and safes it
permanently.
Flush positions of floors with a floor number higher than the number of floors are ignored.
LIMAX44 RED only evaluates the floor information in dual-channel operation (
9.2.1) since a valid test drive
requires that both channels are activated anyway.
9.5.4.1.9
Request for Transition into Safe State
If one of the two channels detects that something is out of order by comparing the position with the other chan-
nel or during the periodic self-diagnostics, a request for transition into safe state is transmitted to the evaluation
unit.
Both channels can request the safe state of the evaluation unit independently of one another. Channel A does
this by setting the position in Segment C to 0. Channel B does this by inverting the CRC check sum.
The frequency of the request for safe state depends on how long the error has been present. There is a distinc-
tion between short-term and long-term interference.
In case of temporary or short-term interference (
12.2.1), the request for transition into safe state is transmitted
with every fourth message (Fig. 26, top). In between the requests, the position is still transmitted to the evalua-
tion unit.
In certain cases it is possible that channel B detects interference while channel A is already sending. In this case,
channel B sends the request for safe state one transmission period earlier than channel A (Fig. 26, bottom). This
can lead to two requests in a row for safe state. The evaluation unit has to tolerate this effect.
In case of long-term interference (
12.2.2), the request for transition into safe state is transmitted with every
message (Fig. 26, centre). A criterion for permanent deactivation is met when the request for transition into safe
state is sent three times in a row.
In case of interference in the position determination (
12.1), the status of short-term interference is not appli-
cable. With these errors, position 0 or the inverted CRC check sum respectively are sent with every message.
