Rs422 Adressable Version (Option A20) - ELGO Electronic EMAX2 Series Operation Manual

6.3.2

RS422 Adressable Version (Option A20)

Protocol of an addressable EMAX2 version 1.4
The device address can be adjusted by a decoding switch which is located behind
a protection cap on the top of the sensor housing:
General format of a message to the EMAX:
0x02 Byte1 Byte2
STX
0x02 (STX) starts a message
0x03 (ETX) close the message
Byte3 (check) is the arithmetic sum of 0x02(STX), Byte1 and Byte2.
ETX is not included in the checksum
General format of a message from the EMAX:
0x02 Byte1 Byte2
STX
Position-request from the EMAX with address i:
Message to the EMAX
0x02 0x04 i check
STX check
0x04 characterizes the message as position-request
i is the address of the requested EMAX2 (i = 0x0b... 0x7f).
Answer of the requested EMAX:
0x02 PosHigh
The position value consists of 3 byte:
PosLow (bit 0... bit 7), PosMid (bit 8... bit15), PosHigh (bit16...bit23).
Bit 0 has the value10 μm. Position-values are always smaller than 0xffff00.
Please note: The last byte is no ETX, like in all the other messages, but the EMAX2 address.
LED Terminating
impedance
Byte3 0x03
check ETX
Byte3 Byte4
0x03
ETX
PosMid PosLow
Address Baud rate
EMAX-Address
15
Installation / Commissioning
Position Address
0 0B
1 0C
2 0D
3 0E
4 0F
5 10
6 11
7 12
8 13
9 14
A 15
B 16
C 17
D 18
E 19
F 1A