Internal Data Structures
Section 4-2
27
4-2 Internal Data Structures
An AS-Interface master uses several lists to keep track of the
communication between the master and the slaves and to exchange data
with the PLC CPU. Data that is used to describe the desired configuration
of the AS-I system is stored in non-volatile memory.
The figure below shows an overview of the master’s lists, and shows how
data is transferred between the CQM1 CPU, these lists, and the slaves.
For normal operation of the CQM1-ARM21, knowledge of its internal data
structures is not essential, but it may help to better understand specific
functions.
Thin lines indicate that data of one particular slave is transferred.
Thick lines indicate all data is transferred at once.
ODI
Output Data Image.
This array contains the data to be transmitted to the active slaves
at the next data exchange.
IDI
Input Data Image.
This array contains the latest actual copies of the received data
from the inputs of all active slaves. Input data of inactive slaves is
set to zero (0).
LDS
List of Detected Slaves.
In this list one bit is set for each slave (0...31) that is detected by
the master (through the start-up operation or inclusion phase).
LAS
List of Activated Slaves.
In this list one bit is set for each slave (1...31) that has been acti-
vated during start-up operation or inclusion phase.
LPS
List of Projected Slaves.
This list contains all slaves (1...31) expected in the AS-Interface
system. The list is created either by local configuration of the
master using Set_Permanent_Configuration commands, or copied
CQM1 CPU
A
S
-I
n
te
rf
a
c
e
T
ra
n
s
m
is
s
io
n
C
o
n
tr
o
l
ODI
IDI
Flags
PP
PI
LPS
LAS
LDS
PCD
CDI
Change_Slave_Address
Write_Parameter
Read_Actual_Configuration
Read_Parameter
Set_Permanent_Parameter
Get_Permanent_Parameter
Set_Permanent_Configuration
Get_Permanent_Configuration
SET switch OFF
→
ON
SET switch OFF
→
ON
At initialisation
At slave activation
At slave detection
SET switch OFF
→
ON
At slave
detection
At slave
activation
IR out
IR in
Control Bits
Status Flags
Each I/O refresh
All active slaves
Continuous checking
Setup Mode Commands
Summary of Contents for CQM1-ARM21
Page 1: ...CQM1 ARM21 AS Interface Master Unit OPERATION MANUAL Cat No W357 E1 1...
Page 2: ......
Page 3: ...CQM1 ARM21 AS Interface Master Unit Operation Manual Produced April 1999...
Page 4: ...iv...
Page 6: ...vi...
Page 8: ...viii...
Page 10: ...x...
Page 30: ...AS Interface Network Installation Section 2 3 16...
Page 38: ...Performance Section 3 3 24...
Page 62: ...Setup Mode Section 4 5 48...
Page 76: ...62...
Page 80: ...66...
Page 84: ......