ADS Environmental Services Model 3600 530002 A2 - Manual (Page 19)

2-4 ADS 3600 Flow Monitor O&M Manual
Side View of Flow Monitor Chassis and Assembly
The board allocates portions of memory to firmware (permanently stored software),
data storage, and program manipulation and calculations. A light-emitting diode
(LED) is located on the processor board and indicates the monitor's communication
status. When the processor board is involved in external communications, the LED is
ON. A second LED is used to indicate the current activity level of the processor
board: the brighter the light, the more work the processor board is doing. Discrete
input and output ports, a monitor clock, and a memory battery are also located on the
board.