Relay Board - Teledyne 300E Instruction Manual

Model 300E Carbon Monoxide Analyzer
Instruction Manual
Electric Test Switch
When active this circuit generates a specific waveform intended to simulate the
function of the IR Photo-Detector but with a known set of value which is substituted
for the detector's actual signal via the Dark Switch. It may also be initiated by the
user (see Section 6.6.4 for more details).

10.3.5. Relay Board

By actuating various switches and relays located on this board, the CPU controls the
status of other key components. The Relay Board receives instructions in the form
of digital signals over the I
its various switches and relays appropriately.
Heater Control
The two heaters attached to the Sample Chamber housing and the GFC Wheel
Motor are controlled by solid state relays located on the Relay Board.
The GFC Wheel Heater is simply turned on or off, however control of the Bench
Heater also includes circuitry that selects which one of its two separate heating
elements is activated depending on whether the instrument is running on 100 VAC,
115 VAC or 230 VAC line power.
GFC Wheel Motor Control:
The GFC Wheel operates from a AC voltage supplied by a multi-input transformer
located on the Relay Board. The step-down ratio of this transformer is controlled by
factory-installed jumpers to adjust for 100 VAC, 115 VAC or 230 VAC line power.
Other circuitry slightly alters the phase of the AC power supplied to the motor
during start up based on whether line power is 50Hz or 60 Hz.
Normally, the GFC Wheel Motor is always turning while the analyzer is on. A
physical switch located on the Relay Board can be used to turn the motor off for
certain diagnostic procedures.
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.
IR Source
The Relay board supplies a constant 11.5VDC to the IR Source. Under normal
operation the IR Source is always on.
P/N 04288 Rev: A
2
C bus, interprets these digital instructions and activates
THEORY OF OPERATION
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