YOKOGAWA F3LA01-0N, User Manual

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3-1
IM 34M6H33-01E 1st Edition : July 1.2004-00
3. Functional Overview
3.1 Functions
The ASi Master Module is compliant to AS-interface V2.1 (including V2.0). It allows the
use of V2.1 functions shown in Table 3.1, provided the connected slaves are AS-
interface V2.1-compliant and support the respective functions. If V2.0-compliant slaves
are connected, only V2.0 functions are available.
The following table shows the differences between AS-interface V2.0 and V2.1.
Intermixing of V2.0-compliant and V2.1-compliant slaves will be discussed later in this
chapter.
Table 3.1 Differences Between ASi V2.0 and V2.1
Address Expansion Function
Maximum
No. of Slaves
Contact Inputs
per Slave
Contact
Outputs per
Slave
Analog
Input/Output
Function
Peripheral Fault Messaging
Function
–
V2.0
31 4 4
– –
V2.1
62 4 3
Contact Input/Output Access Function
Contact inputs of slaves are read into registers of the ASi Master Module, and can then
be read from the Contact Input Data area using a user program.
Contact outputs of slaves can be set by writing to the Contact Output Data area using a
user program. Details of registers are described in the next chapter.
Analog Input/output Access Function
(for V2.1 only)
AS-interface V2.1 allows analog input/output slaves to be connected. Analog data can
then be received and transmitted using commands.
Peripheral Fault Messaging Function
(for V2.1 only)
AS-interface V2.1 supports detection of slave peripheral faults (such as slave auxiliary
power failure, overloading, etc.) by the ASi master. This function allows better system
safety design. The ASi Master Module indicates peripheral faults in its LPF (List of
Peripheral Faults).
I/O Code
Each ASi slave has an I/O code that represents its I/O configuration. A list of available
I/O codes is given in the table below. AS-interface V2.1 allows the maximum allowable
number of connected slaves to be doubled through address extension. To achieve this,
each slave with ID code $A represents a pair of slaves: slave A and slave B. A V2.1
slave with ID code $A uses one output bit (D3) as the selector bit for slave A or slave B.
Hence, no such slave can have input/output or output on bit D3 ($2, $A, and the shaded
area shown below). For details, see the table below.