State Industries GFK-0827 manual Memor y Protect Keyswitch, CPU Status LEDs, Battery Connectors

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Memor y Protect Keyswitch

The Memory Protect keyswitch is located at the top of the module and has two positions: ON and OFF. This keyswitch is used to manually lock program and configuration data. When the key is in the ºprotectedº (ON) position, program and configuration data can only be changed by a programmer connected for parallel communications with the CPU 780 (that is, to the Bus Transmitter Module).

CPU Status LEDs

There are four LEDs mounted at the top of the CPU board which indicate the current state of the CPU. The normal state of these LEDs when the CPU is running is ON. They are OFF or flashing to indicate special or failure conditions.

OK

The top LED, labeled OK is an indicator of the health of the CPU. It is ON when the CPU is functioning properly. The LED blinks when the CPU executes the power-up diagnostics, when the system has failed, and when the remote unit is powered-up. However, when in this state, the CPU can still communicate with the programmer (the CPU cannot communicate with the programmer during power-up diagnostics) . The LED is OFF when the system has failed and the CPU cannot communicate with the programmer.

RUN

The middle LED, labeled RUN is an indicator of the RUN/STOP status of the CPU. It is ON when the CPU is in the RUN/ENABLE or RUN/DISABLE mode. When the CPU is in the STOP mode, the LED is OFF.

ENABLED

The bottom LED, labeled ENABLED indicates the state of the outputs. This LED is ON when the outputs are enabled, and OFF when the outputs are disabled.

MEM PROTECT

This LED indicates the status of the memory protect keyswitch. When the keyswitch is in the OFF position the LED is OFF, and the CPU can be programmed (if connected for parallel communications, the CPU can be programmed regardless of the keyswitch position). After the program has been verified, the toggle switch for mode selection can be moved to the appropriate mode position. When the memory protect keyswitch is in the ON position, the LED will be ON.

Battery Connectors

Directly below the mode switch are two identical battery connectors. The connector wired to the lithium backup battery cable plugs into one of these connectors to connect the battery to the CMOS memory devices. Two connectors are provided for use when the battery requires replacement. The battery currently installed can remain connected until the new battery is connected, thus minimizing the possibility of losing data.

GFK-0827 Chapter 2 System Components 17