Teledyne operating instructions Operational Theory 3000ZA-3X

Page 22

Operational Theory	3000ZA-3X

System power is supplied from a universal power supply module designed to be compatible with any international power source. Figure 2-3 shows the location of the power supply and the main electronic PC boards.

The signal processing electronics including the microprocessor, analog to digital, and digital to analog converters are located on the motherboard at the bottom of the case. The preamplifier board is mounted on top of the motherboard as shown in the figure. These boards are accessible after removing the back panel. Figure 2-4 is a block diagram of the analyzer electronics.

In the presence of oxygen the zirconia sensor generates a current. A current to voltage amplifier converts this current to a voltage, which is amplified in the second stage amplifier. The output from the second stage amplifier is sent to an 18 bit analog to digital converter controlled by the microprocessor. In the block diagram only one sensor is shown, but in reality there are three separate amplifier circuits for each sensor. The output of each sensor is then multiplexed to the analog to digital converter.

The high operating temperature of the ZrO2 sensor is required for proper operation of the sensor. The amplifier PCB contains a circuit that drives the heater embedded in the sensor. The voltage across the heater rises slowly to avoid damaging the heater/sensor assembly. After a few minutes, the sensor will be at the proper operating temperature.

The digital concentration signal along with input from the control panel is processed by the microprocessor, and appropriate control signals are directed to the display, alarms and communications port. The same digital information is also sent to a 12 bit digital to analog converter that produces the 4-20 mA dc and the 0-1 VDC analog concentration signal outputs, and the analog range ID outputs.

Signals from the power supply are also monitored, and through the microprocessor, the system failure alarm is activated if a malfunction is detected.

Teledyne Analytical Instruments

10

Image 22

Contents Model 3000ZA-3X 3000ZA-3X Specific Model Information Important Notice Safety Messages 3000ZA-3X Vii Table of Contents Testing the System Maintenance AppendixModel 3000ZA Front Panel Model 3000ZA Rear PanelList of Tables XiiOverview Main Features of the AnalyzerIntroduction Typical ApplicationsModel Designations Introduction 3000ZA-3XFront Panel Operator Interface Model 3000ZA Front PanelDigital Meter Display Function KeysData Entry Keys Alphanumeric Interface ScreenRear Panel Equipment Interface Access DoorStandby Button ∙ 50-Pin Equipment Interface Port Optional ZrO2 Sensor Operational Theory Introduction Principles of OperationSample System Operational Theory 3000ZA-3XElectronics and Signal Processing Zirconium Oxide Sensor Application NotesOperational Theory 3000ZA-3X Component Location Electronic Block Diagram Unpacking the Analyzer InstallationMounting the Analyzer Installation 3000ZA-3X Rear Panel Connections Gas ConnectionsInstallation3000ZA-3X Zero in and Span in Optional Electrical ConnectionsEquipment Interface Connector Pin Arrangement Threshold Alarm Analog Output ConnectionsSystem Alarm Alarm Relay Contact PinsRemote Calibration Connections Range ID Relay Connections Remote Probe Connections FET Series Resistance 2.3 RS-232 PortCommands via RS-232 Input Installing the Zirconium Oxide Sensors Testing the SystemOperation Style Conventions Using the Data Entry and Function ButtonsKeys Description Enter EscapeAnalyze Screen Menu/Screen StructureSystem Menu Hierarchy of Available Functions Change Password Password routineEnter Password T a Enter New Password T aLogout Routine Model RoutineSelf-Test Routine Analog-Out Adjust RoutineFilter Routine 20mA Gain 20mA Limit False Track in Cal Yes Span Menu Auto-Calibration TimerChange Stream Span Sensor Span TimerSpan Value Span Begin Span FinishSpan Auto Finish Span Begin Begin Span?Zero Finish Zero MenuZero Value Zero Begin Zero TimerZero Timer 7 min Zero Begin Begin Zero?Alarm Polarity Alarms MenuAlarm Active AL-1 NON-LATCHING AL-1 20.00 ppm AL-2 ActiveAlarm Setpoint Alarm FailsafeAlarm Latching AL-1 80.00 ppmRange Select Range MenuRange Select Auto Manual Range Select Range SetpointsSensor Replacement MaintenanceRoutine Maintenance Removing the SensorMaintenance 3000ZA-3X Fuse Replacement Sensor Block with Middle Sensor InstalledSystem Self Diagnostic Test Self-Test Result DisplayMajor Internal Components Rear Panel Removal Remove only those screws marked with anCleaning TroubleshootingTrace Oxygen Analyzer Maintenance Maintenance 3000ZA-3X Teledyne Analytical Instruments Specifications AppendixOperating Temperature 5-35 C Recommended 2-Year Spare Parts List Qty Part Number DescriptionDrawing List 19-inch Relay Rack Panel MountApplication Notes Flow Rate RecommendationsRestriction Devices BY-PASS Conversions