Rs 485 Data Interface - Leuze lumiflex Scan Connecting And Operating Instructions

3.5

RS 485 Data Interface

The signal statuses of the individual light axes ("light path unobstructed" or "light path
interrupted") are transmitted as a serial data stream over the RS 485 interface. The
transmission takes place in half duplex mode at 19.200 baud in the Leuze lumiflex-
specific protocol described below.
The data packet cyclically transmitted by the receiver is configured as follows:
Start identifier
Length of the entire packet
Status
Beam number
Usable data (light path unobstructed)
CRC (8 Bit)
Description:
STK:
LDP:
LDP =
Example:
STA:
8
start identifier constant 0BH
dependent on the beam number (min.9 , max.35)
1 byte(STK) + 1 byte (LDP) + 1 byte (STA) + 1 byte (STZ)
+ x byte (NDT) + 1 byte (CRC)
where: x [NDT] = (STZ/8) rounded up to the next full byte.
STZ = 35:
--> x [NDT] = (35/8) = 4,375 --> x [NDT] = 5 --> LDP = 5 + 5 = 10
STZ = 162:
--> x [NDT] = (162/8) = 20,25 --> x [NDT] = 21 --> LDP = 5 + 21 = 26
STZ = 240:
--> x [NDT] = (240/8) = 30,0 --> x [NDT] = 30 --> LDP = 5 + 30 = 35
Bit 0: 0 = no error , 1 = error/message (in normal operation Bit 0 = 0)
Bit 1: 0 = (internal information)
Bit 2: 1 = (internal information)
Bit 3: 0 = strong receiver signal, 1 = weak receiver signal
Bit 4..5: free
Bit 6: 0 = object in the measurement field,
1 = all light paths unobstructed
Bit 7: 0 = (internal Information)
In case of an error/message (Bit 0 = 1):
Bit 1..5: error number
Bit 6..7: free
(STK) 1 byte
(LDP) 1 byte
(STA) 1 byte
(STZ) 1 byte
(NDT) 1..30 byte
(CRC) 1 byte
SCAN