SST SST-ASI-SLC, User Manual

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SST-ASI-SLC User’s Guide
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4.1 The AS-Interface
The AS-Interface (AS-i) is a master-slave network that offers reliable,
inexpensive digital communications for low level automation such as sensors
and actuators.
The network supports up to 31 slaves and a maximum cable length of 100 m.
With repeaters (2 maximum), the length can reach a maximum of 300 m. The
AS-i cabling contains data and power on a single cable, making setup
extremely easy.
4.2 Scanner Overview
Scanner block diagram
The scanner firmware is stored in flash memory on the scanner. The
EEPROM for each channel contains the network configuration. You can store
a network configuration in the EEPROM in one of two ways:
• Connect to the serial port, select a channel and save.
• Set the G bit in the G file, create a configuration in the G file and
download the program to the SLC. When you put the SLC in run
mode, it writes the configuration in the G file to the EEPROM.
In either case, the SLC compares the contents of the EEPROM with the
network and, if they match, it starts updating I/O. If they don't match, it
generates a fault.
SLC Scan
Shared
Memory
CPU
ASi
Network
Dual Port
Memory
Scan
Dual Port
Memory
Network
Controller
Network
Controller
EEPROM
EEPROM
Network
Interface
Network
Interface
ASi
Network
Scan