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Serial Interface RS422
optoNCDT 1402
Data Protocol ILD14028.3
Setup of the Commands8.3.1
The commands for the sensors are comprised of command data which are transmitted in full duplex mode.
Each command packet is comprised of a whole number multiple of 32 bit words (see Fig. 20).
31 24 23 16 15 8 7 0 Contents
1 Header Start word
Command header (2 words)
2 ID
Sensor identifier,
e.g. “ILD1“
3 Command (16 Bit) Package length (16 Bit) Command code Data word quantity n+2
4 Data 1 1
st
Dats worf (4 Bytes)
5 ... ...
6 Data (n) n
th
Data word (4 Bytes)
Structure of a command packet Fig. 20:
Since most serial interfaces use an 8 bit data format, 4 consecutive bytes are combined into a 32 bit word.
Each command packet has a header consisting of two 32 bit words followed by the command and, if re-
quired, other data as well. The top two bits (No. 31 and 30) are always “0“ in the transmitted command.
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