Teledyne GFC 7001EM operation manual Power SUPPLY/ Circuit Breaker, Power UP Circuit

Theory of Operation Model GFC7001E Carbon Dioxide Analyzer

11.5.7.I2C DATA BUS

An I2C data bus is used to communicate data and commands between the CPU and the keyboard/display interface and the relay board. 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.

Interface circuits on the keyboard/display interface and relay boards convert the I2C data to parallel inputs and outputs. An additional, interrupt line from the keyboard to the motherboard allows the CPU to recognize and service key presses on the keyboard.

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.

11.5.8.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 11-13, 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. The bench and GFC Wheel heaters as well as the GFC Wheel receive AC power via the relay board.

AC Line power is converted stepped down and converted to DC power by two DC power supplies. One supplies +12 VDC, for valves and the IR source, 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.

Teledyne Analytical Instruments 249