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Theory of Operation Teledyne API – Model T300/T300M CO Analyzer
Teledyne
Analytical
Instruments
292
13.4.4.3.
ZERO/SPAN VALVE OPTIONS
Any zero/span/shutoff valve options installed in the analyzer are controlled by a set of
electronic switches located on the relay board. These switches, under CPU control,
supply the +12VDC needed to activate each valve’s solenoid.
13.4.4.4.
IR SOURCE
The relay board supplies a constant 11.5VDC to the IR Source. Under normal operation
the IR source is always on.
13.4.4.5.
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 13-4.
Table 13-4: 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