Rockwell Automation Samsung NX-CPU700p, User Manual, Page: 112 / 122

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Read the content of the bits (R, L, M, K, F, or TC) assigned to the absolute address.
Can read n consecutive bits (On/Off).
Query (Q) frame
Response (R) frame
DA SA $21 $03
BAS
L H
N
CRC
L H
DA SA $A1 N
Base + 0
bit value
Base + 1
bit value
-
Base + N-1
bit value
CRC
L H
Length of information (byte)
Peripheral device ID (PC ID)
Bits that are On are represented by the one byte value $FF.
Bits that are Off have a value of $00.
Absolute bit address (address of
first bit to read)
Refer to 3.3 Absolute Addressing
Ex) K127.12 (address K127’s 12
th
bit)
Absolute bit address = $1BFC
BASE L=$FC, H=$1B
Number of bits to be read
Length of information (number of bytes): from the length to the next CRC.
Response code where $80 is added to the R (Response) Q to its 2-step
communication function code
PLD ID (CPU ID)
Peripheral device ID (PC ID)
For the response, the PLC is the sender and
the PLC the receiver, so the DA and SA are
reversed from the Q message.
PLD ID (PC ID)
Read bits
Function code
(2-step communication)