Principles of Operation Teledyne API T802 Paramagnetic O2 Analyzer Operation Manual
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12.5.6.6. EXTERNAL DIGITAL I/O
This External Digital I/O performs status outputs and control inputs.
STATUS OUTPUTS
Logic-Level voltages are output through an optically isolated 8-pin connector
located on the rear panel of the analyzer. These outputs convey good/bad and
on/off information about certain analyzer conditions. They can be used to
interface with certain types of programmable devices (See Section 3.3.1.5).
CONTROL INPUTS
By applying +5VDC power supplied from an external source such as a PLC or
Data logger (See Section 3.3.1.6), Zero and Span calibrations can be initiated by
contact closures on the rear panel.
12.5.6.7. I2C DATA BUS
I2C is a two-wire, clocked, digital serial I/O bus that is used widely in commercial
and consumer electronic systems. A transceiver on the motherboard converts
data and control signals from the PC-104 bus to I2C. The data is then fed to the
keyboard/display interface and finally onto the relay board.
12.5.6.8. POWER UP CIRCUIT
This circuit monitors the +5V power supply during start-up and sets the Analog
outputs, external digital I/O ports, and I2C circuitry to specific values until the
CPU boots and the instrument software can establish control.
12.5.6.9. POWER SUPPLY / CIRCUIT BREAKER
The analyzer operates on 100 VAC, 115 VAC or 230 VAC power at either 50Hz
or 60Hz. Individual units are set up at the factory to accept any combination of
these five attributes. As illustrated in Figure 12-13, power enters the analyzer
through a standard IEC 320 power receptacle located on the rear panel of the
instrument. From there it is routed through the On/Off switch located in the
lower right corner of the Front Panel. A 6.75 Amp circuit breaker is built into the
ON/OFF Switch.
AC power is distributed directly to the sample gas pump.
AC Line power is stepped down and converted to DC power by two DC power
supplies. One supplies +12 VDC, while a second supply provides +5 VDC and
±15 VDC for logic and analog circuitry. All DC voltages are distributed via the
relay board.
CAUTION
GENERAL SAFETY HAZARD
Should the AC power circuit breaker trip, investigate and correct the condition causing
this situation before turning the analyzer back on.
07275B DCN6418