Teledyne API – Model T300/T300M CO Analyzer
Theory of Operation
299
12.4.4.5.
STATUS LEDS
Eight LEDs are located on the analyzer’s relay board to show the current status on the
various control functions performed by the relay board. They are listed on Table 12-4.
Table 12-4: Relay Board Status LEDs
LED
COLOR
FUNCTION
STATUS WHEN LIT
STATUS WHEN UNLIT
D1
RED
Watch Dog Circuit
Cycles On/Off every 3 seconds under direct control of the analyzer’s
CPU.
D2
YELLOW
Wheel Heater
HEATING
NOT HEATING
D3
YELLOW
Bench Heater
HEATING
NOT HEATING
D4
YELLOW
Spare
N/A
N/A
D5
GREEN
Sample/Cal Gas Valve
Option
Valve Open to CAL GAS FLOW
Valve Open to SAMPLE Gas Flow
D6
GREEN
Zero/Span Gas Valve Option
Valve Open to SPAN GAS FLOW
Valve Open to ZERO GAS FLOW
D7
GREEN
Shutoff Valve Option
Valve Open to CAL GAS FLOW
Valve CLOSED to CAL GAS
FLOW
D8
GREEN
IR SOURCE
Source ON
Source OFF
Figure 12-15: Location of relay board Status LEDs
12.4.4.6.
I2C WATCH DOG CIRCUITRY
Special circuitry on the relay board monitors the activity on the I
2
C bus and drives LED
D1. Should this LED ever stay ON or OFF for 30 seconds, the watch dog circuit will
automatically shut off all valves as well as turn off the IR Source and all heaters. The
GFC Wheel motor will still be running as will the Sample Pump, which is not controlled
by the relay board.
06864D DCN7562
Summary of Contents for T300
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