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Thermo Electron 48C Instruction Manual

Gas filter correlation co analyzer
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MODEL 48C
GAS FILTER CORRELATION CO ANALYZER
INSTRUCTION MANUAL
P/N 42P255
THERMO ELECTRON CORPORATION
ENVIRONMENTAL INSTRUMENTS
27 FORGE PARKWAY FRANKLIN MASSACHUSETTS 02038
(866) 282-0430 Toll Free
(508) 520-0430 International
(508) 520-1460 Fax
www.thermo.com/eid
3Mar2004
The 220V option complies with 89/336/EEC directive for electromagnetic compatibility.

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  • Page 1 MODEL 48C GAS FILTER CORRELATION CO ANALYZER INSTRUCTION MANUAL P/N 42P255 THERMO ELECTRON CORPORATION ENVIRONMENTAL INSTRUMENTS 27 FORGE PARKWAY FRANKLIN MASSACHUSETTS 02038 (866) 282-0430 Toll Free (508) 520-0430 International (508) 520-1460 Fax www.thermo.com/eid 3Mar2004 The 220V option complies with 89/336/EEC directive for electromagnetic compatibility.
  • Page 2 © 2003 Thermo Electron Corporation. All rights reserved. Thermo Electron Corporation, question everything, and Analyze. Detect. Measure. Control are trademarks of Thermo Electron Corporation. All other product names and logos are the property of their respective owner. Specifications, terms and pricing are subject to change. Not all products are available in all countries.
  • Page 3 REFERENCE METHOD DESIGNATION The Thermo Environmental Instruments, Inc. Model 48C is designated by the United States Environmental Protection Agency (USEPA) as a Reference Method for the measurement of ambient concentrations of Carbon Monoxide pursuant with the requirements defined in the Code of Federal Regulations, Title 40, Part 53.

  • Page 5: Table Of Contents

    TABLE OF CONTENTS CHAPTER 1 INTRODUCTION .................1-1 Principle of Operation...................... 1-1 Specifications........................1-3 CHAPTER 2 INSTALLATION................2-1 Lifting..........................2-1 Unpacking ........................2-1 Setup Procedure ....................... 2-2 Analog Output Cover Installation ................ 2-4 Startup ..........................2-6 CHAPTER 3 OPERATION ................3-1 Display ..........................3-1 Pushbuttons ........................
  • Page 6 Calibration Menu ......................3-21 Calibrate Zero ....................3-22 Calibrate Span....................3-23 Instrument Controls Menu ..................... 3-24 Temperature Correction ..................3-25 Pressure Correction .................... 3-26 Baud Rate......................3-27 Instrument ID ..................... 3-28 Screen Brightness....................3-29 Service Mode ..................... 3-30 Time ........................3-31 Date ........................
  • Page 7 Service Mode Menu ....................... 3-63 Pressure ......................3-64 Flow ........................3-65 Intensity Check....................3-66 A/D Frequency....................3-67 Temperature Compensation Coefficient ............3-69 Initial S/R Ratio ....................3-70 Hi or Lo Multi-Point Calibration ............... 3-71 Default Coefficients .................. 3-73 Relay Logic ......................3-74 Set Test Display ....................
  • Page 8 CHAPTER 5 PREVENTIVE MAINTENANCE...........5-1 Spare Parts ........................5-1 Cleaning the Optics......................5-1 IR Source Replacement....................5-2 System Leaks and Pump Check Out ................5-2 External Leaks...................... 5-3 Leaks Across the Optional Zero/Span Solenoid Valves ........5-3 CHAPTER 6 TROUBLESHOOTING ..............6-1 Troubleshooting Guide ....................
  • Page 9 CHAPTER 8 THEORY OF OPERATION............8-1 Electronics........................8-1 DC Power Supply....................8-1 Bias Power Supply....................8-1 Detector and Preamplifier ..................8-2 Input Signal Conditioning Board ................. 8-2 Temperature Control Board ................. 8-3 The Microprocessor System................. 8-3 Display Module..................8-3 Processor Board ..................8-3 Analog to Digital Board................
  • Page 10 APPENDIX C SCHEMATICS ................C-1 Motherboard........................C-2 Pushbutton Board 1......................C-3 Pushbutton Board 2......................C-3 Processor Board .......................C-4 Analog/Digital Board.......................C-5 Digital/Analog Board.......................C-6 Power Supply Board ......................C-7 Preamplifier........................C-8 Input Board ........................C-9 Bias Power Supply Board ....................C-10 Temperature Control Board ...................C-11 C-Link Board .........................C-12 4-20 mA Outputs (optional)...................C-13 Input/Output Board (optional) ..................C-14 Rear Connector Interface Board..................C-15 APPENDIX D PUMP MAINTENANCE.............
  • Page 11 LIST OF ILLUSTRATIONS FIGURE PAGE Model 48C Flow Schematic................. 1-2 Model 48C Rear Panel ..................2-3 Atmospheric Dump Bypass plumbing ..............2-3 Shielded Cable with Shielding Pulled Back ............2-4 Exploded View of Analog Output Cover Installation.......... 2-5 Properly Installed Shield Cable................2-6 Model 48C Front Panel..................
  • Page 13 LIST OF TABLES TABLE PAGE Available Operating Ranges ................3-12 A/D Converters ....................3-67 Option Switch Functions..................3-77 Operating Mode Truth Table ................3-78 Scrubbing Materials ..................... 4-2 Recommended Spare Parts .................. 5-1 Replacement Parts....................7-2 Instrument Status Output Truth Table ..............9-9 Current Output Channel with Corresponding Concentration ......

  • Page 15: Chapter 1 Introduction

    The Model 48C uses an exact calibration curve to accurately linearize the instrument output over any range up to a concentration of 10,000 ppm.
  • Page 16 Thus the GFC system responds specifically to CO. The Model 48C outputs the CO concentration to the front panel display and the analog outputs.

  • Page 17: Specifications

    Chapter 1 Introduction SPECIFICATIONS Preset ranges 0-1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000, 10000 ppm 0-1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000, 10000 mg/m Custom ranges 0-1 to 10000 ppm 0-1 to 10000 mg/m Zero noise 0.02 ppm RMS (30 second time setting)

  • Page 19: Chapter 2 Installation

    UNPACKING The Model 48C is shipped complete in one container. If, upon receipt of the analyzer, there is obvious damage to the shipping container, notify the carrier immediately and hold for inspection.
  • Page 20 Modes” in Chapter 3 for the pin-out of the rear panel terminals in each operating mode. 4. Plug the instrument into an outlet of the appropriate voltage and frequency. CAUTION: The Model 48C is supplied with a three-wire grounding cord. Under no circumstances should this grounding system be defeated.
  • Page 21 Chapter 2 Installation Figure 2-1. Model 48C Rear Panel 42P730 Figure 2-2. Atmospheric Dump Bypass Plumbing 57P7100...

  • Page 22: Analog Output Cover Installation

    Chapter 2 Installation Analog Output Cover Installation This analog output cover must be mounted over the analog outputs to comply with 89/336/EEC Directive. This procedure describes how to install the user-supplied analog output cable in the instrument’s analog output cover. The following shielded cables or their equivalent are recommended: Cable Gauge...
  • Page 23 Chapter 2 Installation Follow the procedure below to prepare the shielded cable: 1. Remove about 1.8 cm of insulation from the cable. 2. Fold back the shielding. 3. Use electrical tape or shrink tubing to hold the shielding in place. Be sure at least 1.5 cm of shielding is exposed.

  • Page 24: Startup

    Chapter 2 Installation Figure 2-5. Properly Installed Shield Cable 1. Install cable clamp into shield cover and secure. Be sure there is good electrical conductivity between clamp and shield cover. The following is a parts list of components in the analog output cover assembly: Part No.

  • Page 25: Chapter 3 Operation

    Run screen. The Run screen displays the CO concentration. In addition, the pushbutton is used to switch the optional zero/span and sample solenoid valves. For more information about the optional solenoid valves, see Chapter 9, “Optional Equipment.” Figure 3-1. Model 48C Front Panel 42P730...

  • Page 26: Menu Pushbutton

    ) move the cursor up, down, right, and left. SOFTWARE OVERVIEW The Model 48C is based on menu-driven software as illustrated by the flowchart in Figure 3-2. The Power-Up and Self Test screens, shown at the top of the flowchart, are displayed each time the instrument is turned on.
  • Page 27 Chapter 3 Operation...

  • Page 28: Power-Up Screen

    Chapter 3 Operation Power-Up Screen The Power-Up screen, as shown below, is displayed on power up of the Model 48C. THERMO ENVIRONMENTAL INSTRUMENTS MODEL 48C Power-Up Screen Self Test Screen The Self Test Screen, as shown below, is displayed while the internal components are warming up and a diagnostic check is performed.

  • Page 29: Run Screen

    Chapter 3 Operation Run Screen The standard Run screen, as shown below, displays the CO concentration. It also displays time and the status of the RS-232 interface and optional zero/span and sample solenoid valves, if installed. The word “Sample” on the bottom left of the display indicates the analyzer has the span/zero valve option and is in “SAMPLE”...

  • Page 30: Range Menu

    Chapter 3 Operation RANGE MENU The Range menu contains the gas units, CO ranges, and the custom ranges. In the upper right-hand corner of the display, the word single, dual, or auto is displayed to indicate the active mode. The Range menu in the dual and autorange modes appear the same except for the word dual or auto, displayed in the upper right-hand corner.

  • Page 31: Single Range Mode

    Chapter 3 Operation Single Range Mode In single range mode, there is one range, one averaging time, and one span coefficient. The two CO analog outputs are arranged on the rear panel terminal strip as shown in Figure 3-3. To use the single range mode, set option switches 4 and 5 off. For more information about setting the internal option switches, see “Internal Option Switches,”...

  • Page 32: Autorange Mode

    Chapter 3 Operation There are two ranges, high CO range and low CO range, that correspond to the high CO and low CO analog outputs, respectively. There are two span coefficients so that each range can be calibrated separately. This may be necessary if the two ranges are not close to one another.
  • Page 33 Chapter 3 Operation To use the autorange mode, option switches 4 and 5 must be on. For more information about setting the internal option switches, see “Internal Option Switches,” later in this chapter When the high CO range is active, the concentration must drop to 95% of the low CO range for the low CO range to become active.

  • Page 34: Gas Units

    Chapter 3 Operation Gas Units The Gas Units screen, shown below, defines how the CO concentration reading is expressed. Gas Units of parts per million (ppm) and milligrams per cubic meter (mg/m are available. The mg/m gas concentration mode is calculated using a factory standard pressure of 760 mm Hg and a factory standard temperature of 20 °...

  • Page 35: Co Range

    Chapter 3 Operation CO Range The CO range defines the concentration range of the analog outputs. For example, a CO range of 0-50 ppm restricts the analog output to concentrations between 0 and 50 ppm. The second line of the display shows the current CO range. The third line of the display is used to change the range.
  • Page 36 Chapter 3 Operation mg/m 1,000 1,000 2,000 2,000 5,000 5,000 10,000 10,000 Table 3-1. Available Operating Ranges C1, C2, and C3 are custom ranges. For more information about custom ranges, see “Custom Ranges Menu” below. 3-12...

  • Page 37: Custom Ranges Menu

    Chapter 3 Operation Custom Ranges Menu The Custom Ranges Menu, shown below, lists three custom ranges: C1, C2, and C3. Custom ranges are user-defined ranges. In the ppm mode, any value between 1 and 10,000 ppm can be specified as a range. In the mg/m mode, any value between 1 and 10,000 mg/m can be specified.

  • Page 38: Custom Range Screen

    Chapter 3 Operation Custom Range Screen. The Custom Range screen, shown below, is used to define the custom range. The first line of the display shows the current custom range. The second line of the display is used to set the range. To use the custom fullscale range, be sure to select C1, C2, or C3 in the CO Range screen.

  • Page 39: Averaging Time

    Chapter 3 Operation AVERAGING TIME The averaging time defines a time period (1 to 300 seconds) during which CO measurements are taken. The average concentration of the readings are calculated for that time period. The front panel display and analog outputs are updated every 10 seconds for averaging times between 10 and 300 seconds.

  • Page 40: Calibration Factors Menu

    Chapter 3 Operation CALIBRATION FACTORS MENU Calibration factors are determined during automatic and manual calibration and are used to correct the CO concentration readings. The Calibration Factors menu displays the calibration factors as shown below. Normally the instrument is calibrated automatically, that is, introduce the span gas and use the Calibration Screen.

  • Page 41: Co Background Correction

    Chapter 3 Operation CO Background Correction The CO background correction is determined during zero calibration. The CO background is the amount of signal read by the analyzer while sampling zero air. The background signal is electrical noise. Before the analyzer sets the CO reading to zero, it stores the value as the CO background correction.

  • Page 42: Co Background

    Chapter 3 Operation CO Background To display the CO Background screen: From the Main Menu choose Calibration Factors From the Calibration Factors menu choose CO Background To use the CO Background screen: Use the ↑ and ↓ pushbuttons to increment/decrement the CO background Press to accept a change in the background ENTER...

  • Page 43: Co Span Gas

    Chapter 3 Operation CO Span Gas The CO span gas is set prior to calibration. The span gas is used to calibrate the CO level. To display the CO Span Gas screen: From the Main Menu choose Calibration Factors From the Calibration Factors menu choose Span Gas To use the CO Span Gas screen: Use the ↑...

  • Page 44: Co Span Coefficient

    Chapter 3 Operation CO Span Coefficient The CO span coefficient is calculated during calibration. The span coefficient is used to correct the CO readings and normally has a value near 1.000. The CO Span Coefficient screen enables the CO span coefficient to be manually changed while sampling span gas of known concentration.

  • Page 45: Calibration Menu

    Chapter 3 Operation CALIBRATION MENU The Calibration menu is used to calibrate zero and span. The calibration menu is similar for the single, dual, and autorange mode as shown below. The dual and autorange modes have two CO span factors (hi and lo). This allows each range to be calibrated separately. This may be necessary if the two ranges used are not close to one another, for example a low CO range of 50 ppm and a high CO range of 1000 ppm.

  • Page 46: Calibrate Zero

    Chapter 3 Operation Calibrate Zero The Calibrate Zero screen, shown below, is used to perform a zero calibration. Be sure the analyzer samples zero air until stable readings are obtained. The first line of the display shows the current CO reading. For more information about the CO background, see “CO Background Correction,”...
  • Page 47 Chapter 3 Operation Calibrate CO The Calibrate CO screen is used to adjust the CO span concentration while sampling span gas of known concentration. The first line of the display shows the current CO concentration reading. The second line of the display shows the current CO range.

  • Page 48: Instrument Controls Menu

    Chapter 3 Operation INSTRUMENT CONTROLS MENU The Instrument Controls menu is shown below. This menu contains items that control general instrument operations. To display the Instrument Controls Menu: From the Main Menu choose Instrument Controls To use the Instrument Controls Menu: Use the ↑...

  • Page 49: Temperature Correction

    Chapter 3 Operation Temperature Correction Temperature correction provides compensation for any changes to the instrument's output signal due to internal instrument temperature variations. The effects of internal instrument temperature changes on the analyzer's subsystems and output have been empirically determined. Changes in temperature are corrected by this empirical data.

  • Page 50: Pressure Correction

    Chapter 3 Operation Pressure Correction Pressure correction provides compensation for any changes to the instrument's output signal due to optical chamber pressure variations. The effects of chamber pressure variations on the analyzer's subsystems and output has been empirically determined. Changes in optical chamber pressure are corrected by this empirical data.

  • Page 51: Baud Rate

    Chapter 3 Operation Baud Rate The Baud Rate screen, shown below, is used to set the RS-232 interface baud rate. Baud rates of 1200, 2400, 4800, and 9600 are available. To display the Baud Rate screen: From the Main Menu choose Instrument Controls From the Instrument Controls menu choose Baud Rate To use the Baud Rate screen: Use the ↑...

  • Page 52: Instrument Id

    This is useful if two or more of the same instrument are connected to one computer. Valid Instrument ID numbers are from 0 to 99. The Model 48C has a default Instrument ID of 48. For more information about the Instrument ID, see Appendix B, “RS-232 Commands.”...

  • Page 53: Screen Brightness

    Chapter 3 Operation Screen Brightness The Screen Brightness screen, shown below, is used to change the screen brightness. Intensities of 25%, 50%, 75%, and 100% are available. Changing the screen brightness to a lower intensity will extend the life of the display. To display the Screen Brightness screen: From the Main Menu choose Instrument Controls From the Instrument Controls menu choose Screen Brightness...

  • Page 54: Service Mode

    The Service Mode screen, shown below, is used to turn the service mode on and off. The service mode includes parameters and functions that are useful when making adjustments or diagnosing the Model 48C. For more information about the service mode, see “Service Mode Menu,” later in this chapter.

  • Page 55: Time

    Chapter 3 Operation Time The internal clock is set by the Time screen as shown below. The first line of the display shows the current time (military). The second line of the display is used to change the time. The internal clock is powered by its own battery when instrument power is off.

  • Page 56: Date

    Chapter 3 Operation Date The date is set by the Date screen as shown below. The first line of the display shows the current date. The second line of the display is used to change the date. The date is updated by the internal clock. To display the Date screen: From the Main Menu choose Instrument Controls From the Instrument Controls menu choose Date...

  • Page 57: Diagnostics Menu

    Chapter 3 Operation DIAGNOSTICS MENU The Diagnostics menu, shown below, provides access to diagnostic information and functions. This menu is useful when troubleshooting the instrument. To display the Diagnostics menu: From the Main Menu choose Diagnostics To use the Diagnostics menu: Use the ↑...

  • Page 58: Program Number

    Chapter 3 Operation Program Number The Program Number screen, shown below, shows the version numbers of the programs installed. Prior to contacting the factory with any questions regarding the instrument, please note the program numbers. To display the Program Number screen: From the Main Menu choose Diagnostics From the Diagnostics menu choose Program Number To use the Program Number screen:...

  • Page 59: Voltages

    Chapter 3 Operation Voltages The Voltages screen as shown below, displays the current dc power supply voltages. This enables the power supply to be quickly tested for low or fluctuating voltages without having to use a voltage meter. To display the Voltages screen: From the Main Menu choose Diagnostics From the Diagnostics menu choose Voltages To use the Voltages screen:...

  • Page 60: Temperatures

    Chapter 3 Operation Temperatures The Temperatures screen, as shown below, displays the current internal instrument temperature and chamber temperature. To display the Temperatures screen: From the Main Menu choose Diagnostics From the Diagnostics menu choose Temperatures To use the Temperatures screen: This is a view only screen Press to return to the Diagnostics menu...

  • Page 61: Pressure

    Chapter 3 Operation Pressure The Pressure screen, shown below, displays the current optical chamber pressure. The pressure is measured by an internal pressure transducer. To display the Pressure screen: From the Main Menu choose Diagnostics From the Diagnostics menu choose Pressure To use the Pressure screen: This is a view only screen Press...

  • Page 62: Flow

    Chapter 3 Operation Flow The Flow screen, shown below, displays the current sample flow rate. The flow is measured by an internal flow sensor. To display the Flow Screen: From the Main Menu choose Diagnostics From the Diagnostics menu choose Flow To use the Flow screen: This is a view only screen Press...

  • Page 63: Sample/Reference Ratio

    Chapter 3 Operation Sample/Reference Ratio The Sample/Reference Ratio screen, shown below, displays the ratio of the intensities of the light source through the sample (CO) side and reference (N side of the correlation wheel. Normally, when zero air is being sampled, the sample/reference ratio is between 1.14 and 1.18.

  • Page 64: Agc Intensity

    The AGC Intensity screen, shown below, displays the intensity (in Hertz) of the reference channel Automatic Gain Control (AGC) circuit. The AGC circuit optimizes the noise and resolution levels of the Model 48C. The AGC intensity reading should be about 250,000 Hertz.

  • Page 65: Motor Speed

    Chapter 3 Operation Motor Speed The Motor Speed screen, shown below, displays the status of the chopper motor. A reading of 100.0% means that the motor speed is correct. A reading other than 100.0% indicates that there is a problem with the chopper motor or power supply. To display the Motor Speed screen: From the Main Menu choose Diagnostics From the Diagnostics menu choose Motor Speed...

  • Page 66: Test Analog Outputs

    Chapter 3 Operation Test Analog Outputs The Test Analog Outputs menu contains three choices as shown below. These functions enable the analog outputs to be set to zero and fullscale in order to adjust the analog outputs to agree with the front panel display. In addition, a digital to analog (DAC) ramp can be generated to fully test the analog outputs.

  • Page 67: Zero

    Chapter 3 Operation Zero. The Zero screen, as shown below, sets the analog outputs to zero volts. Use the ↑ and ↓ pushbuttons to increment/decrement the output level. For example, to set the analog outputs to 5%, use the ↑ pushbutton to increment the 0.0 to 5.0%.

  • Page 68: Fullscale

    Chapter 3 Operation Fullscale. The Fullscale screen, as shown below, sets the analog outputs to fullscale. Use the ↑ and ↓ pushbuttons to increment/decrement the output level. For example, to set the analog outputs to 95%, use the ↓ pushbutton to decrement the 100.0 to 95.0%.

  • Page 69: Ramp

    Chapter 3 Operation Ramp. The digital to analog (DAC) ramp is used to fully test the analog outputs. The analog outputs start at -2.3% and then increments by 0.1% every second until it reaches 100.0%. A linear output indicates that the analog outputs are operating correctly.

  • Page 70: Option Switches

    Chapter 3 Operation Option Switches The Option Switches screen, shown below, enables the settings of the internal option switches to be viewed. Use the ↑ and ↓ pushbuttons to view entire list. Option switch settings can not be changed through the software. For more information about the internal option switches, see “Internal Option Switches”...

  • Page 71: Alarms

    Chapter 3 Operation ALARMS The Alarms menu, shown below, displays a list of items that are monitored by the analyzer. If the item being monitored goes outside the lower or upper limit, the status of that item will go from OK to either LOW or HIGH, respectively. The number in the upper right-hand corner of the display indicates how many alarms have occurred.

  • Page 72: Internal Temperature

    Chapter 3 Operation Internal Temperature The Internal Temperature screen, shown below, displays the current internal temperature and factory-set min and max limits. The min and max alarm limits can be changed when the instrument is in the service mode. Acceptable alarm limits range from 8 to 47 C.

  • Page 73: Min And Max Internal Temperature Limits

    Chapter 3 Operation Min and Max Internal Temperature Limits. The Min Internal Temperature limit screen, shown below, is accessible only when the instrument is in the service mode. It is used to change the min internal temperature alarm limit. The min and max Internal Temperature screens function the same way.

  • Page 74: Chamber Temperature

    Chapter 3 Operation Chamber Temperature The Chamber Temperature screen, shown below, displays the current chamber temperature and the factory-set min and max alarm limits. The min and max alarm limits can be changed when the instrument is in the service mode. Acceptable alarm limits range from 40 to 52 C.

  • Page 75: Min And Max Chamber Temperature Limits

    Chapter 3 Operation Min and Max Chamber Temperature Limits. The Min Chamber Temperature limit screen, shown below, is accessible only when the instrument is in the service mode. It is used to change the min chamber temperature alarm limit. The min and max Chamber Temperature screens function the same way.

  • Page 76: Pressure

    Chapter 3 Operation Pressure The Pressure screen, shown below, displays the current optical chamber pressure reading and the factory-set min and max alarm limits. The min and max alarm limits can be changed when the instrument is in the service mode. Acceptable alarm limits range from 250 to 1,000 mm Hg.

  • Page 77: Min And Max Pressure Limits

    Chapter 3 Operation Min and Max Pressure Limits. The Min Pressure limit screen, shown below, is accessible only when the instrument is in the service mode. It is used to change the min pressure alarm limit. The min and max Pressure screens function the same way. To display the Min or Max Pressure limit screen (service mode on): From the Main Menu choose Alarm From the Alarm menu choose Pressure...

  • Page 78: Flow

    Chapter 3 Operation Flow The Flow screen, shown below, displays the current sample flow reading and the factory- set min and max alarm limits. The min and max alarm limits can be changed when the instrument is in the service mode. Acceptable alarm limits range from 0 to 1 LPM. If the flow reading goes beyond either the min or max alarm limit, an alarm is activated.

  • Page 79: Min And Max Flow Limits

    Chapter 3 Operation Min and Max Flow Limits. The Min Flow limit screen, shown below, is accessible only when the instrument is in the service mode. It is used to change the min flow alarm limit. The min and max Flow screens function the same way. To display the Min or Max Flow limit screen (service mode on): From the Main Menu choose Alarm From the Alarm menu choose Sample Flow...

  • Page 80: Bias Voltage

    Chapter 3 Operation Bias Voltage The Bias Voltage screen, shown below, displays the current bias voltage and the factory- set min and max alarm limits. The min and max alarm limits can be changed when the instrument is in the service mode. Acceptable limits range from -130 to -100 volts. If the bias voltage reading goes beyond either the min or max alarm limit, an alarm is activated.

  • Page 81: Min And Max Bias Voltage Limits

    Chapter 3 Operation Min and Max Bias Voltage Limits. The Min Bias Voltage limit screen, shown below, is accessible only when the instrument is in the service mode. It is used to change the min bias voltage alarm limit. The min and max Bias Voltage screens function the same way.

  • Page 82: Agc Intensity

    Chapter 3 Operation AGC Intensity The AGC Intensity screen, shown below, displays the current AGC Intensity reading and the factory-set min and max alarm limits. The min and max alarm limits can be changed when the instrument is in the service mode. Acceptable alarm limits range from 150,000 to 300,000 Hertz.

  • Page 83: Min And Max Agc Intensity Limits

    Chapter 3 Operation Min and Max AGC Intensity Limits. The Min AGC Intensity limit screen, shown below, is accessible only when the instrument is in the service mode. It is used to change the min AGC intensity alarm limit. The min and max AGC Intensity screens function the same way.

  • Page 84: Motor Speed

    Chapter 3 Operation Motor Speed The Motor Speed screen, shown below, displays the current motor speed. A reading other 100.0% indicates a problem with either the motor or the power supply board. To display the Motor Speed screen: From the Main Menu choose Alarm From the Alarm menu choose Motor Speed To use the Motor Speed screen: Use the ↑...

  • Page 85: Co Concentration

    Chapter 3 Operation CO Concentration The CO Concentration screen, shown below, displays the current CO concentration and the factory-set max alarm limit. The max alarm limit can be changed when the instrument is in the service mode. Acceptable alarm limits range from 0 to 10,000 ppm. If the CO concentration in single mode or low CO concentration in dual or auto range mode exceeds the max alarm limit, an alarm is activated.
  • Page 86 Chapter 3 Operation Max CO Concentration Limits. The Max CO Concentration limit screen, shown below, is accessible only when the instrument is in the service mode. It is used to change the maximum CO concentration alarm limit. Setting the maximum alarm level to 00000.0 disables the alarm.

  • Page 87: Service Mode Menu

    Chapter 3 Operation SERVICE MODE MENU The Service Mode menu, shown below, appears only when the instrument is in the service mode. To put the instrument into the service mode, select Instrument Controls from the Main Menu, from the Instrument Controls menu select Service Mode. When the instrument is in the service mode, the Main Menu extends to include the Service Mode menu.

  • Page 88: Pressure

    Chapter 3 Operation Pressure The Pressure screen, shown below, shows the fluorescence chamber pressure. The fluorescence chamber pressure is updated every second. This screen is used while adjusting the pressure transducer potentiometers. CAUTION: Some internal components can be damaged by small amounts of static electricity.

  • Page 89: Flow

    Chapter 3 Operation Flow The Flow screen, shown below, shows the flow reading. The flow reading is updated every second. This screen is used while the flow sensor potentiometers are adjusted. The potentiometer closest to the floor plate is the zero adjust potentiometer and the potentiometer farthest from the floor plate is the span potentiometer.

  • Page 90: Intensity Check

    Chapter 3 Operation Intensity Check The Intensity Check screen, shown below, is used to turn the automatic gain control (AGC) circuit on and off. To display the Intensity Check screen: From the Main Menu choose Service Mode From the Service Mode menu choose Intensity Check To use the Intensity Check screen: Press to turn the AGC circuit on and off...

  • Page 91: A/D Frequency

    Chapter 3 Operation A/D Frequency The A/D Frequency screen, shown below, displays the frequency of each of the 12 analog to digital (A/D) converters located on the A/D Board. Each A/D has a frequency range between 0 and 100,000 Hertz. This frequency range corresponds to a voltage range of 0 to -10 volts dc.
  • Page 92 Chapter 3 Operation To display the A/D Frequency screen: From the Main Menu choose Service Mode From the Service Mode menu choose A/D Frequency To use the A/D Frequency screen: Use the ↑ and ↓ pushbuttons to increment/decrement the A to D number Press to return to the Service Mode menu MENU...

  • Page 93: Temperature Compensation Coefficient

    Chapter 3 Operation Temperature Compensation Coefficient The Temperature Compensation Coefficient is used to compensate for the effects of ambient temperatures on the zero stream. The temperature compensation coefficient can be set by to different means, “Auto Set” which, is automatically calculated based on a span gas reading at a previously stored temperature and the current temperature, and “Adjust”...

  • Page 94: Initial S/R Ratio

    Chapter 3 Operation Initial S/R Ratio The Initial S/R Ratio screen, shown below, displays both the initial S/R ratio and the current S/R ratio. The initial S/R ratio is determined at the factory, and is used to correct for the slight variations found from one correlation wheel to another. The only time the initial S/R ratio should be changed is when the correlation wheel is replaced or after factory consultation.

  • Page 95: Hi Or Lo Multi-Point Calibration

    Chapter 3 Operation Hi or Lo Multi-Point Calibration Up to three gas concentrations (cal-points) for each range may be calibrated to using the following steps. Three cal-points will give the most accurate readings over the entire range. The Calibration process is sequential and will only work properly if all steps are followed in order.
  • Page 96 Chapter 3 Operation To use the Hi or Lo Multi-Point Cal Screen. NOTE: If only using one span gas, simply skip setting Cal points 2 and 3 below. Select Cal point 1 While running span gas 1 (typically 80% of the range) through the instrument, use the ←...
  • Page 97 Chapter 3 Operation Default Coefficients The Default Coefficient Screen is used prior to a calibration when there has been a bad calibration or new ranges have been set up. To view the Default Coef Screen From the Main Menu Select Service Mode From the Service Mode Menu select Hi or Lo Multi Point Cal From Hi or Lo Multi-Point Cal select Default Coef COEF 0...

  • Page 98: Relay Logic

    Chapter 3 Operation Relay Logic The Relay Logic Screen allows the user to change the I/O relays to either normally open or normally closed. To view the Rely Logic Screen: From the Main Menu select Service Mode From the Service Mode select Relay Logic RELAY LOGIC NORMALLY OPEN...

  • Page 99: Set Test Display

    Chapter 3 Operation Set Test Display The Set Test Display screen, shown below, displays the contents of a given memory location. This screen is useful to TEI service personnel only. To display the Set Test Display screen: From the Main Menu choose Service Mode From the Service Mode menu choose Set Test Display To use the Set Test Display screen: Use the ↑...

  • Page 100: Internal Option Switches

    Chapter 3 Operation INTERNAL OPTION SWITCHES The internal option switches are located on the motherboard (near front panel), as shown in Figure 3-7 below. The function of each option switch is given in Table 3-3. These switches are used to activate hardware and software options. CAUTION: Some internal components can be damaged by small amounts of static electricity.

  • Page 101: Remote

    Chapter 3 Operation Option Switch Function Remote RS-232 Zero/Span and Sample Solenoid Valves Double Range Autorange Lock Spare Factory Set Table 3-3. Option Switch Functions Remote Option switch 1 is on when a remote interface is installed, such as RS-232 or I/O activation.

  • Page 102: Double Range And Autorange

    Chapter 3 Operation Double Range and Autorange The double range (option switch 4) and autorange (option switch 5) switches are used to activate the dual and autorange modes. Table 3-3 shows how each mode is activated. For more information about the single, dual, and autorange modes, see “Operating Modes,”...

  • Page 103: Chapter 4 Calibration

    CO concentrations in the 0.1 - 0.3 ppm range. Thus cylinder zero air should be scrubbed of the residual CO prior to its use in the Model 48C as a dilution gas or a zero standard. Room air which has been scrubbed of CO can be used as the zero air source. It is not...

  • Page 104: Flow Meter(S) And Controller(S)

    Chapter 4 Calibration Compression. The zero air source should be at an elevated pressure to allow accurate and reproducible flow control and to aid in subsequent operations such as drying, oxidation, and scrubbing. An air compressor that gives an output of 10 psig is usually sufficient for most applications.

  • Page 105: Pressure Regulator For Co Standard Cylinder

    PRE-CALIBRATION Prior to calibration, be sure the Model 48C is operating properly. The Model 48C's internal diagnostics makes this a quick and simple process. Turn on the instrument and allow it to stabilize for one hour.

  • Page 106: Zero Adjust

    Since not all flow controllers have a positive shut off, it might be necessary to disconnect the CO input line and cap it. Allow the Model 48C to sample zero air until a stable reading is obtained. From the Main Menu choose Calibration.
  • Page 107 = flow rate of CO standard corrected to 25 ° C and 760 mm Hg, LPM = flow rate of dilution air corrected to 25 ° C and 750 mm Hg, LPM Allow the Model 48C to sample this CO concentration standard until a stable response is obtained.

  • Page 108: Additional Concentration Standards

    These checks can be performed by: 1. Periodically challenging the Model 48C with zero air. The output of the zero air supply should be greater than the flow demand of the Model 48C. In addition, an atmospheric dump bypass should be utilized to ensure that the zero air gas flow is being delivered at atmospheric pressure.

  • Page 109: References

    Chapter 4 Calibration 2. Periodically challenging the Model 48C with a CO level of approximately 80% of the URL. The 80% URL level may be obtained by dilution of a higher level of CO using a system similar to that of Figure 4-1, or by using a low level cylinder of CO containing CO in air at a concentration of approximately 80% of the URL.

  • Page 110: Hi And Lo Multi-Point Calibration

    Chapter 4 Calibration HI AND LO MULTI-POINT CALIBRATION The Model 48C CO Analyzer can be calibrated using a dual three-point calibration. The calibration points are divided into a “low” range and a “high” range consisting of three points each Cal Point 1, Cal Point 2, and Cal Point 3. The customer decides the ranges and TEI recommends calibrations points of 80% (Cal Point 1), 50% (Cal Point 2), and 20% (Cal Point 3) of the range selected.
  • Page 111 = flow rate of CO standard corrected to 25 ° C and 760 mm Hg, LPM = flow rate of dilution air corrected to 25 ° C and 750 mm Hg, LPM Allow the Model 48C to sample this CO concentration standard until a stable response is obtained.

  • Page 113: Chapter 5 Preventive Maintenance

    PREVENTIVE MAINTENANCE This chapter describes the periodic maintenance procedures that should be performed on the Model 48C to ensure proper, uninterrupted operation. Certain components such as the sample pump, solenoid valves, and IR source have a limited life and should be checked on a regular calendar basis and replaced if necessary.

  • Page 114: Ir Source Replacement

    After cleaning the optics, the IR light intensities remain below 100,000 Hz. Since the Model 48C is a ratio instrument, and since replacing the IR source does not affect the calibration, it is not necessary to recalibrate the Model 48C after replacing the IR source.

  • Page 115: External Leaks

    Chapter 5 Preventive Maintenance External leaks To test for the presence of leaks around the fittings, disconnect the sample input line and plug the fitting. The flow as read in the Flow screen (Diagnostics menu) should SAMPLE slowly decrease to zero. The pressure as read in the Pressure screen (Diagnostics menu) should drop to below 250 mm Hg.

  • Page 117: Chapter 6 Troubleshooting

    CHAPTER 6 TROUBLESHOOTING The Model 48C has been designed to achieve a high level of reliability. Only premium components are used, thus complete failure is rare. In the event of problems or failure, the troubleshooting guidelines presented in this chapter should be helpful in isolating the fault(s).
  • Page 118 Run output noisy Recorder noise Replace or repair recorder Sample CO concentration Run Model 48C on a span CO varying source - if quiet, there is no malfunction Foreign material in Clean optical bench...
  • Page 119 Chapter 6 Troubleshooting MALFUNCTION POSSIBLE CAUSE ACTION Analog test ramp Faulty recorder Replace recorder D/A calibration off Recalibrate the D/A with a DMV known to be in calibration Digital electronics Replace one board at a time defective with a spare board to isolate the defective board...

  • Page 121: Chapter 7 Servicing

    CHAPTER 7 SERVICING This chapter explains how to replace the Model 48C subassemblies. Fault location is accomplished in the preceding chapters of “Preventive Maintenance” and “Troubleshooting.” This chapter assumes that a subassembly has been identified as defective and needs to be replaced. For additional service assistance, see “Servicing Locations”...

  • Page 122: Replacement Parts List

    Chapter 7 Servicing REPLACEMENT PARTS LIST Table 7-1 lists the part numbers of the major subassemblies in the Model 48C. Refer to Figure 7-2 to identify their location. Part Number Description 9831 Motherboard 9837 Processor Board 9849 Analog/Digital Board 9839...
  • Page 123 Chapter 7 Servicing...

  • Page 124: Ir Source Replacement

    7. Re-install the instrument cover. 8. Let the Model 48C sample zero air for about 90 minutes. 9. From the Service Mode menu, select Initial S/R Ratio, which should be between 1.14 and 1.18.
  • Page 125 Chapter 7 Servicing...

  • Page 126: Chopper Motor Replacement

    Chapter 7 Servicing Figure 7-4. Optical Bench 48OPT CHOPPER MOTOR REPLACEMENT Equipment required: New Chopper Motor (Part No. 4735) Allen Wrenches - 5/32" and 5/64" Screwdriver 1. Wear an antistatic wrist strap, see “Safety Precautions,” earlier in this chapter for more information.

  • Page 127: Optical Switch Replacement

    Chapter 7 Servicing 2. Disconnect power and remove cover. 3. Disconnect all connections between the optical bench and the electronics. 4. Remove the four screws holding the optical bench to the shock mounts and carefully remove the optical bench. 5. Replace the optical bench by following the above directions in reverse. 6.

  • Page 128: Preamplifier/Detector Assembly Replacement

    Chapter 7 Servicing PREAMPLIFIER/DETECTOR ASSEMBLY REPLACEMENT Equipment required: Detector Assembly (Part No. 8938), (Preamplifier Board - Part No. 7363) Screwdriver 1. Wear an antistatic wrist strap, see “Safety Precautions,” earlier in this chapter for more information. 2. Disconnect power and remove cover. 3.

  • Page 129: Pump Replacement

    Chapter 7 Servicing Figure 7-5. Pump Assembly Diagram 93P737 PUMP REPLACEMENT Equipment required: Pump (Part No. 8550 (110V) or 8551 (220V)) Nut Driver Screwdriver 1. Wear an antistatic wrist strap, see “Safety Precautions,” earlier in this chapter for more information. 2.

  • Page 130: Pressure Transducer Replacement

    Chapter 7 Servicing 7. Install the new pump by following the above procedure in reverse. 8. Re-install the instrument cover. 9. Perform a leak test as described in Chapter 5, “Preventive Maintenance.” PRESSURE TRANSDUCER REPLACEMENT Equipment required: Pressure Transducer (Part No. 9877) Nut Driver 1.

  • Page 131: Input Signal Conditioning Board Replacement

    Chapter 7 Servicing INPUT SIGNAL CONDITIONING BOARD REPLACEMENT Equipment required: Nut Driver Input Signal Conditioning Board (Part No. 9989) 1. Wear an antistatic wrist strap, see “Safety Precautions,” earlier in this chapter for more information. 2. Disconnect power and remove cover. 3.

  • Page 132: Capillary Removal

    Chapter 7 Servicing CAPILLARY REMOVAL Equipment required: Capillary (Part No 7336) Wire to clean old capillary 1. Wear an antistatic wrist strap, see “Safety Precautions,” earlier in this chapter for more information. 2. Disconnect power and remove cover. 3. Remove the capillary from the inlet elbow fitting on the pump head. 4.
  • Page 133 Chapter 7 Servicing 3. From the Run screen, press the pushbutton to display the Main Menu. Use the MENU ↓ pushbutton to move the cursor to Diagnostics, and press to display the ENTER Diagnostics menu. Use the ↓ pushbutton to move the cursor to Test Analog Outputs, and press .

  • Page 134: Pressure Transducer Adjustment

    Chapter 7 Servicing Fullscale Analog Outputs Screen 6. Repeat the above steps to ensure the adjustments are accurate. 7. Re-install the instrument cover. PRESSURE TRANSDUCER ADJUSTMENT This procedure should only be performed by an instrument service technician. Equipment Required: Vacuum Pump Screwdriver CAUTION: Some internal components can be damaged by small amounts of static electricity.

  • Page 135: Temperature Sensor Adjustment

    Since the thermistors used in the Model 48C are interchangeable to an accuracy of ± 0.2 ° C, and have a value of 10K ohms at 25 ° C, an alternate procedure is to connect an accurately known 10K resistor to the thermistor input on the Motherboard, and potentiometer for an internal temperature reading of 25 °...

  • Page 136: Fuse Replacement

    Chapter 7 Servicing FUSE REPLACEMENT Equipment Required: 115V T, 3A, 250V (Part No. 4510) 220V T, 1.25A, 250V (Part No. 14009) 1. Disconnect power to instrument. 2. Remove fuse drawer, located on the AC power connector. 3. Replace both fuses, if either is blown. 4.
  • Page 137 Chapter 7 Servicing SERVICE LOCATIONS For additional assistance, Environmental Instruments Division has service available from exclusive distributors worldwide. Contact one of the phone numbers below for product support and technical information. 866-282-0430 Toll Free 508-520-0430 International 7-17...

  • Page 139: Chapter 8 Theory Of Operation

    CHAPTER 8 THEORY OF OPERATION In order to fully understand the operation of the Model 48C, a general knowledge of the electronics, software, and subassemblies is necessary. ELECTRONICS The electronics can be broken down into the following subassemblies: DC Power Supply...

  • Page 140: Detector And Preamplifier

    Chapter 8 Theory of Operation Detector and Preamplifier The detector used on the Model 48C is a Photo Conductive, Lead-Selenide (PbSe) device, with an internal thermoelectric cooler. The PbSe detector operates through use of the internal photoelectric effect. That is, its conductivity is proportional to the high intensity hitting it. One characteristic of this device is that it has a high conductivity even with no light.

  • Page 141: Temperature Control Board

    Chapter 8 Theory of Operation Temperature Control Board Two 50 watt 100 ohm resistors (400 ohm for 220 V) mounted on the optical bench are used to heat the optical bench above the dew point, to avoid moisture condensation on the mirrors.

  • Page 142: Software

    It is important to understand this for troubleshooting. Ten pulses equal one second. The Model 48C operates on a ten second cycle. Thus 100 reset pulses corresponds to one full cycle. Every five seconds a signal is sent to the input signal conditioning board changing which V-F receives the sample signal and which one the reference signal.

  • Page 143: Subassemblies

    Chapter 8 Theory of Operation If a time constant other than 10 seconds is set, the program takes the average over the proper number of values. Thus if a time constant of 60 seconds is set, the program will retrieve the past six measurements, take the average, and output this information to the display and analog outputs.

  • Page 144: Flow Components

    Chapter 8 Theory of Operation Flow Components The Model 48C operates at normal atmospheric pressure. Figure 1-1 summarizes the flow schematic. A downstream pump and capillary control the sample flow through the optical bench, which is monitored by a flow sensor. The nominal flow is 1 liter per minute, with values between 1/2 - 2 liters per minute acceptable.

  • Page 145: Chapter 9 Optional Equipment

    CHAPTER 9 OPTIONAL EQUIPMENT This chapter describes the Model 48C optional equipment. RACK MOUNTS WITH SLIDES Rack mounts with slides for standard 19-inch relay racks are available. Figure 9-1 illustrates the installation of the rack mount option. The mounting hardware is installed on the analyzer at the factory.
  • Page 146 Chapter 9 Optional Equipment...

  • Page 147: Internal Zero/Span And Sample Solenoid Valves

    Chapter 9 Optional Equipment INTERNAL ZERO/SPAN AND SAMPLE VALVES With the zero/span and sample valve option, a source of span gas is connected to the port and a source of zero air is connected to the port (see Figure 2-1). Zero SPAN ZERO and span gas should be supplied at atmospheric pressure.
  • Page 148 Chapter 9 Optional Equipment Zero/Span Check Menu To set zero/span check, follow the procedure below: 1. Set the date of the first zero/span check. The Next Date screen, shown below, is used to set the initial or start date of the zero/span check. Once the initial zero/span check is performed, the date of the next zero/span check is calculated and displayed.
  • Page 149 Chapter 9 Optional Equipment Next Time Screen 3. Set the period between zero/span checks. The Period screen, shown below, defines the period or interval between zero/span checks. Periods between 2 and 1,000 hours are acceptable. To turn the zero/span check off, set the period to 0. Period Screen Set the zero check and the span check duration.

  • Page 150: Remote Activation Of Zero/Span And Sample Valves

    Chapter 9 Optional Equipment REMOTE ACTIVATION OF ZERO/SPAN AND SAMPLE VALVES The rear panel I/O (DB25) connector, shown in Figure 9-3, enables the zero/span and sample valves to be remotely controlled via contact closure. In addition, the connector has several instrument status outputs. Option switch 1 must be on and option switch 2 off in order to enable the remote I/O connector.

  • Page 151: Input Pins

    Chapter 9 Optional Equipment Input Pins To activate the zero gas mode, connect pin 1, 6, 14, or 19 (ground) to pin 5 (zero gas mode), as shown in Figure 9-4. To deactivate the zero gas mode, disconnect ground from the zero gas mode input.

  • Page 152: Instrument Status Outputs

    Chapter 9 Optional Equipment Instrument Status Outputs Several instrument status outputs are available on the rear panel I/O connector via reed relays on the I/O Board. The reed relays are arranged as shown in Figure 9-6. In the instrument status output truth table, each pin is referred to as open or closed (based on the physical position of the corresponding relay).

  • Page 153: 4-20 Ma Isolated Current Output

    Chapter 9 Optional Equipment The following table is for when the relays are set to normally open. Status Relay Closed Relay Open Concentration Alarm Alarm No Alarm Local or Remote Mode Local or Service Mode Remote Mode MG/M or PPM Mode mg/m mode ppm mode...

  • Page 154: Teflon Particulate Filter

    Chapter 9 Optional Equipment TEFLON PARTICULATE FILTER A 5-10 micron pore size, 2 inch diameter Teflon → element is available for the Model 43C. This filter should be installed just prior to the bulkhead. When using a SAMPLE filter, all calibrations and span checks must be performed through the filter. PURGE HOUSING This housing is attached between the optical bench and Bodine8 motor faceplate (Figure 9-8).
  • Page 155 Chapter 9 Optional Equipment 9-11...

  • Page 156: Instrument Handle

    Chapter 9 Optional Equipment INSTRUMENT HANDLE An instrument handle is available to aid in carrying the instrument. It also enables the instrument to be slightly elevated, while resting on a table or bench, to increase visibility of the display. Figure 9-9 shows the installation of the instrument handle. Figure 9-9.

  • Page 157: Appendix Awarranty

    APPENDIX A WARRANTY Seller warrants that the Products will operate substantially in conformance with Seller's published specifications, when subjected to normal, proper and intended usage by properly trained personnel, for 13 months from date of installation or 12 months from date of shipment, whichever is less (the "Warranty Period").
  • Page 159 APPENDIX B RS-232/485 COMMANDS RS-232/485 COMMANDS The RS-232/485 interface enables the analyzer to be remotely controlled by a host remote device such as, a PC, PLC, datalogger, etc. On the rear panel of the analyzer there are two male DB9 connectors. Both connectors are identical, so either can be connected to the remote device.

  • Page 160: Appendix B Rs-232 Commands

    The analyzer must be in the remote mode in order to change instrument parameters via RS-232. However, the command "set mode remote" can be sent to the Model 48C to put it in the remote mode. Report commands can be issued either in the remote or local mode.
  • Page 161 Appendix B RS-232 Commands set zero This command sets the optional valves to the zero mode. The example sets the instrument in the zero mode, that is, the instrument is sampling zero air. Send: "set zero" Receive: "set zero ok" set span This command sets the optional valves to the span mode.
  • Page 162 Appendix B RS-232 Commands co bkg This command reports the current CO background. The example below reports that the CO background is 1.4 ppm. Send: "co bkg" Receive: "co bkg 1.400 ppm" set co bkg dd.ddd This command is used to set the CO background to a user-defined value. The example below sets the CO background to 1.4 ppb.
  • Page 163 Appendix B RS-232 Commands set co coef d.ddd set low co coef d.ddd The “set co coef” command sets the CO coefficient to a user-defined value in the single range and sets the high coefficient in the dual or auto range. The “set low co coefficient” sets the low coefficient in the dual or auto range.
  • Page 164 Appendix B RS-232 Commands relay status The “relay status” command reports the relay status (normally open or normally closed) of the input/output relays. Send: "relay status" Receive: "relay status open" set relay open The “set relay (open or closed)” command sets the logic state of the output relays to open or closed.
  • Page 165 Appendix B RS-232 Commands gas unit This reports the current gas units (ppm or mg/m ). The example reports that the gas unit is set to ppm. Send: "gas unit" Receive: "gas unit ppm" set gas unit unit unit = | ppm | mg/m3 | This command sets the gas units to ppm or mg/m .
  • Page 166 Appendix B RS-232 Commands set range d set low range d d = Code in table below The “set range” command selects the CO fullscale range according to the table below for single mode and sets the high range for dual and auto range. The “set low range” command sets the low range in dual or auto range.
  • Page 167 Appendix B RS-232 Commands custom d d = | 1 | 2 | 3 | This reports the user-defined value of custom range 1, 2, or 3. The example below reports that custom range 1 is defined to 55.0 ppm. Send: "custom 1"...
  • Page 168 Appendix B RS-232 Commands set avg time d set low avg time d d = Code in table below The “set avg time” command sets the averaging time according to the Table below for single mode and sets the high averaging time in dual or auto mode. The “set low avg time”...
  • Page 169 Appendix B RS-232 Commands internal temp This reports the current internal instrument temperature. The first temperature reading is the temperature being used in instrument calculations. The second temperature is the actual temperature being measured. If temperature compensation is on, then both temperature readings are the same.
  • Page 170 Appendix B RS-232 Commands pres This reports the current reaction chamber pressure. The first pressure reading is the pressure reading being used in instrument calculations. The second pressure is the actual pressure reading being measured. If pressure compensation is on, then both pressure readings are the same.
  • Page 171 Appendix B RS-232 Commands set time hh:mm:ss hh = hours mm = minutes ss = seconds Sets the internal clock (military time). The example below sets the internal time to 2:15 pm. Note that if seconds are omitted, the seconds default to 00. Send: "set time 14:15"...
  • Page 172 Appendix B RS-232 Commands ratio The “ratio” command reports the current sample/reference ratio. When operating in dual or auto range this command reports the sample/reference ratio calculated using the high averaging time. The example below shows that the current ratio is 1.16110. Send: "ratio"...
  • Page 173 Appendix B RS-232 Commands flow This reports the current sample flow. The example below reports that the current sample flow is 1.108 liters/minute. Send: "flow" Receive: "flow 1.108 l/m" dtoa d d = DTOA in table below This reports the outputs of the 7 Digital to Analog converters (0000 = 0.0% FS, 1000 = 100.0% fullscale).
  • Page 174 Appendix B RS-232 Commands program no This reports the analyzer's program number and the Link (communications) program number. The example below shows that the installed processor program is 48 00000100 and the installed communication program (link) is 48L 00000100. Send: "program no"...
  • Page 175 = | run | menu | enter | help | up | down | left | right | This command is used to simulate pressing the Model 48C front panel pushbuttons. In the example below, the push command is used in conjunction with the screen command to view the Main Menu.
  • Page 176 Appendix B RS-232 Commands set bright d This command sets the display’s brightness level. d= 0, 1, 2, or 3. 0 = 25% 1 = 50% 2 = 75% 3 = 100% The example below sets the display’s level of brightness to 50% Send: "set bright 2"...
  • Page 177 Appendix B RS-232 Commands format This command reports the current reply termination format as shown below: Send: "format" Receive: "format 00" Code Reply Termination <CR> 0x80 xxxx <CR> where xxxx = the sum of all characters in the message set format dd dd = | 00 | 01 | This command sets the reply termination format.
  • Page 178 Appendix B RS-232 Commands B-20...
  • Page 179 Appendix B RS-232 Commands Records There are two types of records that can be stored: long records (lrec) and short (srec) records. In addition, there is dynamic data (erec) that is constantly updated during the operation of the instrument. Both long and short records contain the time, date, flags, and concentrations; long records also contain internal temperature, chamber temperature, pressure, sample flow, motor speed, bias voltage, and agc intensity.
  • Page 180 Appendix B RS-232 Commands srec mem size This command reports the maximum number of short records that can be stored with the current settings and the number of blocks reserved for short records. The example below is for a short record. Send: "srec mem size"...
  • Page 181 Appendix B RS-232 Commands set srec per dd dd =  1  5  15  30  60  This command sets the srec logging period to every dd minutes. Send: "set srec per 15" Receive: "set srec per 15 ok" lrec per This command reports the lrec logging period.
  • Page 182 Appendix B RS-232 Commands Record Formats Long and short records, and dynamic data can be output in various formats such as ASCII without text, ASCII with text, or binary (see Table B-1 for codes). The following commands report and set the current output format for long (lrec) and short records (srec), and dynamic data (erec).
  • Page 183 Appendix B RS-232 Commands lrxy, srxy, erxy These commands report the last long or short record stored, or the current dynamic data record. The x can be a 0 or 1, 0=no check sum returned, 1= check sum returned. The y is the format code, which can be 1, 2, or 3 their functions are located in Table B-1 “Format Codes”.
  • Page 185 SCHEMATICS This appendix contains the schematics for the standard and optional printed circuit boards contained in the Model 48C. Always turn off the instrument and unplug the power cord before removing any printed circuit board. For more information about appropriate safety precautions, see Chapter 7, “Servicing.” A description of each board can be found in Chapter 8, “Theory of Operation.”...
  • Page 194 C-10...
  • Page 195 C-11...
  • Page 196 C-12...
  • Page 197 C-13...
  • Page 198 C-14...
  • Page 199 C-15...
  • Page 201 APPENDIX D PUMP MAINTENANCE...

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