Alert Alphabot, User Manual

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Alphabot User Manual
Safety
1000004-MN-01 - Rev C Page 38 of 77
2.2.6 Description of the Alphabot System E-Stop Circuitry
The Alphabot System uses a certified safety-programmable logic controller (“Master
SPLC”) located in the main electrical enclosure. The main architecture includes
conventional Safety I/O modules, and the Actuator Sensor interface (ASi) technology for
safe & common connections to devices such as the emergency stop devices, safety
interlocks, and conventional proximity sensors.
The emergency stop buttons are located at each operator station, on main enclosures,
and at the rear of the structure, at each level. These "E-Stop" buttons are connected on
the ASi bus within the system, originating from the ASi power supply and associated
safety node in the main enclosures. The Ethernet communication permits the
transmission of safe information throughout the entire system network. Any E-stop
button activated within the system will generate a category 1 stop to the Bots per NFPA
79 and IEC 60204-1, and automatically de-energize the power to the rails.
Each Bot is provided with a certified simplified Bot SPLC to communicate via wireless
Ethernet with the Master SPLC, and with a main CPU, to communicate with the Master
Control Software (MCS) for operational purposes. A category 1 stop provides a Bot
controlled stop with final power removal of drive motor, tote motor, and applied brakes
to drive motors. The Bot SPLC directly removes the power to the redundant contactors,
de-energizing the charging rails in the entire system as a category 0 stop.
A red LED is on at the depressed E-Stop button, as well as the electrical enclosures' tower
lights. Each Bot is safely-stopped, with their red LEDs blinking red as well.
In order to start the system again, the E-Stop button must be unlatched (twist and/or pull
to release) and any reset button must be pressed.
The E-stop circuitry corresponds to a Category 3 PLd per EN ISO 13849-1 and SIL2 per IEC
62061.