Beckhoff KL5121, Документация

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Access from the user program
KL5121 36 Version: 3.1.0
Control byte in the register mode
MSB
REG = 1 W/R A5 A4 A3 A2 A1 A0
REG = 0: Process data exchange
REG = 1: Access to register structure
W/R = 0: Read register
W/R = 1: Write register
A5...A0 = register address
Addresses A5...A0 can be used to address a total of 64 registers
Examples for the register communication
Fig. 15: Register mode control byte
The control or status byte occupies the lowest address of a logical channel. The corresponding register
values are located in the following 2 data bytes. (The BK2000 is an exception: here, an unused data byte is
inserted after the control or status byte, and the register value is therefore placed on a word boundary).
Sample 1
Reading register 8 in the BK2000 with a KL5121 and the end terminal:
If the following bytes are transferred from the controller to the terminal,
Byte Byte 3 Byte 2 Byte 1 Byte 0
Name DataOUT 1, low byte DataOUT 0, high byte Not used Control byte
Value 0xXX 0xXX 0xXX 0x88
The terminal returns the following type identifier (0x1401 corresponds to unsigned integer 5121).
Byte Byte 3 Byte 2 Byte 1 Byte 0
Name DataIN 1, low byte Data IN 0, high byte Not used Status byte
Value 0x01 0x14 0x00 0x88