NIBA-01 Installation and Start-up Guide
6-1
Chapter 6 – Communication
Overview
This chapter describes the messaging used in InterBus-S
communication. Further information is available from the host controller
documentation, Phoenix Contact (http://www.phoenixcontact.com),
and the INTERBUS Club (http://www.interbusclub.com).
Interbus-S
Message Frame
The Interbus-S system employs so-called summation frames. The host
controller cyclically sends a message frame that includes the process
data for every module on the bus. The frame is constructed by the host
controller using the configuration data entered previously for each
module on the bus.
As the message frame is relayed through the system, each device on
the bus stores the information addressed to it in a buffer and responds
by writing a response message into the same position in the frame. As
the message frame returns to the host controller, it is checked against
the original message.
Figure 6-1 InterBus-S message frame.
LOOP
CHECK
PROCESS
DATA
MODULE 1
MODULE 2
MODULE 3
MODULE n-1
MODULE n
FRAME
PROCESS
DATA
PARAM-
ETER
HEADER
SERVICE
INDEX
VALUE
CONTROL
PARAM-
ETER
HEADER
SERVICE
INDEX
VALUE
PROCESS
DATA
PROCESS
DATA
2nd CYCLE
3rd CYCLE
4th CYCLE
5th CYCLE
IN
OUT
BYTE 8
BYTE 7
BYTE 6
BYTE 5
BYTE 4
BYTE 3
BYTE 2
BYTE 1
PCP CHANNEL*
PCP CHANNEL*
DATA SET 1 DATA WORD 2 (DW 1.2)
REFERENCE 1 (REF1)
DATA SET 1 DATA WORD 1 (DW 1.1)
CONTROL WORD (CW)
DATA SET 1 DATA WORD 3 (DW 1.3)
REFERENCE 2 (REF2)
DATA SET 2 DATA WORD 1 (DW 2.1)
STATUS WORD (SW)
DATA SET 2 DATA WORD 2 (DW 2.2)
ACTUAL VALUE 1 (ACT1)
DATA SET 2 DATA WORD 3 (DW 2.3)
ACTUAL VALUE 2 (ACT2)
2 BYTES
2 BYTES
4 BYTES
4 BYTES
8 BYTES
2 BYTES
2 BYTES
2 BYTES
CHECK
SEQUENCE
PROCESS
DATA
*USED IN PCP MODE ONLY.
SEE PCP SERVICES
SUPPORTED BY NIBA-01
BELOW.
