IDEC MicroSmart - Manual (Page 444)

28: AS-I NTERFACE M ASTER C OMMUNICATION
28-4 « FC4A M ICRO S MART U SER ’ S M ANUAL »
Main Features of AS-Interface V2 with Slave Expansion Capability
The AS-Interface is a reliable bus management system in which one master periodically monitors each slave device con-
nected on the AS-Interface bus in sequence. The master manages the I/O data, parameters, and identification codes of each
slave in addition to slave addresses. The management data depends on the type of the slave as follows:
Standard Slaves
• A maximum of four inputs and four outputs for each slave
• Four parameters for setting a slave’s operation mode (P3, P2, P1, P0)
• Four identification codes (ID code, I/O code, ID2 code, and ID1 code)
A/B Slaves
• A maximum of four inputs and three outputs for each slave
• Three parameters for setting a slave’s operation mode (P2, P1, P0)
• Four identification codes (ID code, I/O code, ID2 code, and ID1 code)
Note 1: Parameters P3 through P0 are used to set an operation mode of the slave. For details, see the user’s manual for
the slave.
Note 2: The slaves connected to the AS-Inter face bus are distinguished from each other by the ID code and I/O code con-
tained in each slave. Some slaves have ID2 code and ID1 code to indicate the internal functions of the slave. For example,
analog slaves use the ID2 code to represent the channel number of the slave.
Note 3: The MicroSmar t AS-Inter face master module is also compatible with AS-Inter face ver. 2.1 and earlier slaves.
Slave Addresses
Each standard slave connected to the AS-Interface bus can be allocated an address of 1 through 31. Each A/B slave can be
allocated an address of 1A through 31A or 1B through 31B. All slaves are set to address 0 at factory before shipment. The
address of a slave can be changed using the “addressing tool.” Using
WindLDR , the addresses of slaves connected to the
AS-Interface master module can also be changed (see page 28-31).
When a slave fails during operation and needs to be replaced, if the auto addressing function is enabled on the master mod-
ule, just replace the slave with a new one (with address 0 and the same identification codes). The new slave will automati-
cally be allocated the same address as the slave that was removed, and you do not have to set the address again. For details
of the ASI command to enable auto addressing, see page 28-28.
Slave Identification
Slaves have the following four identification codes. The master checks the identification codes to determine the type and
feature of the slave connected on the AS-Interface bus.
ID Code
The ID code consists of 4 bits to indicate the type of the slave, such as sensor, actuator, standard slave, or A/B slave. For
example, the ID code for a standard remote I/O is 0, and that for an A/B slave is A (hex).
I/O Code
The I/O code consists of 4 bits to indicate the quantity and allocation of I/O points on a slave.
I: input, O: output, B: input and output
ID2 Code
The ID2 code consists of 4 bits to indicate the internal function of the slave.
ID1 Code
The ID1 code consists of 4 bits to indicate additional identification of the slave. Standard slaves can have an ID1 code of
0000 through 1111 (bin). A/B slaves use the MSB to indicate A or B slave, and can have a unique value only for the lower
three bits. The MSB of A slaves is set to 0, and that of B slaves is set to 1.
I/O Code Allocation I/O Code Allocation I/O Code Allocation I/O Code Allocation
0h I, I, I, I 4h I, I, B, B 8h O, O, O, O Ch O, O, B, B
1h I, I, I, O 5h I, O, O, O 9h O, O, O, I Dh O, I, I, I
2h I, I, I, B 6h I, B, B, B Ah O, O, O, B Eh O, B, B, B
3h I, I, O, O 7h B, B, B, B Bh O, O, I, I Fh (reser ved)