National Oceanic and Atmospheric Administration 

Environmental Protection Agency 

Ultraviolet Radiation and Ozone Monitoring 

Brewer Network 

Brewer Site Operators Handbook 

Prepared by 

NOAA/ESRL/GMD 

Solar Radiation Research Branch 

Boulder, Colorado 

Version 1.0 

June 8, 2006 

Contents 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 i

Document #: TBD

Version 1.0

Table of Contents 

1 Introduction 1-1 

1.1 Brewer MKIV Spectrophotometer 1-1 

1.2 Standard Maintenance Procedures 1-2 

1.3 Precautions 1-2 

1.4 Required Tools and Supplies 1-3 

1.4.1 Tools 1-3 

1.4.2 Supplies 1-3 

2 Site Visit Procedures 2-1 

2.1 Logging Visits and Changes to the System 2-1 

2.1.1 The Log Book 2-1 

2.1.2 Electronic Log Entries 2-1 

2.2 Daily/Weekly Maintenance Procedures 2-1 

2.2.1 Brewer Computer System Checks - Daily 2-2 

2.2.2 Brewer Checks – Daily/Weekly 2-2 

2.2.3 Tracker Checks – Bi-Monthly 2-3 

3 Brewer Control Computer 3-1 

3.1 Hardware Configuration 3-1 

3.2 Windows Software Configuration 3-1 

3.2.1 PC Operating System 3-2 

3.2.2 PC Brewer Software 3-2 

3.2.3 PC Remote Control Software 3-3 

3.2.4 PC Time-Keeping Software 3-3 

3.2.4.1 NIST Time Program 3-3 

3.2.4.2 PC Clock Program 3-4 

3.2.5 PC Automatic Reboot 3-6 

3.2.6 PC System Uptime Monitor 3-7 

3.2.7 PC Scheduling Software 3-7 

3.3 Brewer-to-PC Communications Interface 3-9 

3.3.1 RS-232 3-9 

3.3.2 RS-485 Converters 3-10 

3.3.2.1 ICC-11 RS-232-RS485 Converter 3-10 

3.3.2.2 IC-485s RS-232-RS-485 Converter 3-10 

4 Brewer Spectrophotometer Maintenance 4-1 

4.1 Cleaning External UV Dome and Quartz Window 4-1 

4.2 Enclosure Cover Removal and Maintenance 4-1 

4.3 Checking Humidity Indicators 4-2 

4.3.1 Humidity Monitor Strip 4-2 

4.3.2 Breather Tube Desiccant 4-3 

4.3.3 Spectrometer Humidity Indicator 4-3 

4.4 Desiccants 4-3 
Contents 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 ii

Document #: TBD

Version 1.0

4.4.1 Changing Desiccant Packs 4-3 

4.4.2 Changing Breather Tube Desiccant 4-4 

4.5 Sun Sighting Alignment 4-4 

4.5.1 Procedure 4-4 

4.5.2 Sun Sighting Troubleshooting 4-10 

5 Tracker Maintenance 5-1 

5.1 Tracker Mechanical Inspection 5-1 

5.2 Tracker Azimuth Wheel Maintenance 5-1 

5.3 Tracker Over-Rotation Protection Switch 5-3 

Appendix A Day of Year Calendars A-1 

List of Figures 

Figure 1-1 Complete Brewer Spectrophotometer System 1-1 

Figure 1-2 Top View of Brewer Enclosure 1-2 

Figure 2-1 Brewer Status and Operation Indicators 2-2 

Figure 2-2 Humidity Indicator 2-3 

Figure 3-1 Windows Task Bar on Brewer PC with Internet Connectivity 3-2 

Figure 3-2 Brewer Software Display Information 3-3 

Figure 3-3 NIST Time Client Window 3-4 

Figure 3-4 PC Clock Program Window 3-5 

Figure 3-5 PC Clock Configuration Screen 3-5 

Figure 3-6 WinOFF Reboot Clock 3-6 

Figure 3-7 WinOFF Shut down programming Screen 3-6 

Figure 3-8 WinOFF Options Screen 3-7 

Figure 3-9 System Uptime Monitor Screen 3-8 

Figure 3-10 Macro Scheduler Software 3-8 

Figure 3-11 RS-485 Converter By-Passed in Brewer Chassis 3-9 

Figure 3-12 RS-485 Converter Connected in the Brewer Chassis 3-10 

Figure 3-13 ICC-11 RS-485 Converter Wiring Diagram 3-11 

Figure 3-14 IC-485s RS-485 Converter Wiring Diagram 3-12 

Figure 4-1 Brewer Routine Glass Cleaning 4-1 

Figure 4-2 UV Dome Protector 4-1 

Figure 4-3 Inside Cover Weather-Seal 4-2 

Figure 4-4 Latch Maintenance 4-2 

Figure 4-5 Humidity Indicator Locations 4-2 

Figure 4-6 Humidity Monitor Strip 4-2 

Figure 4-7 Breather Tube Desiccant 4-3 

Figure 4-8 Spectrometer Humidity Indicator 4-3 
Contents 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 iii

Document #: TBD

Version 1.0

Figure 4-9 Desiccant Pack Locations 4-4 

Figure 4-10 Brewer Computer Display 4-5 

Figure 4-11 Brewer SI Command Screen 4-6 

Figure 4-12 Overview of the Brewer Sun Sighting Mechanism 4-6 

Figure 4-13 Visible shadow caused by Brewer's azimuth alignment being rotated too far 

in the clockwise (CW) direction 4-7 

Figure 4-14 Brewer with proper azimuth alignment. No shadow may also indicate 

azimuth is rotated too far in the counter- clockwise (CCW) direction 4-7 

Figure 4-15 Zenith Prism Maximum Rotations 4-8 

Figure 4-16 Looking through sighting tubes without blocking the Quartz Window from 

the Sun 4-9 

Figure 4-17 Locations of Tracker Sighting Adjustment Buttons 4-9 

Figure 4-18 Image of Sun improperly aligned on the on face of the Iris 4-9 

Figure 4-19 Image of Sun properly aligned on the face of the Iris 4-9 

Figure 4-20 Entrance Slit improperly aligned 4-10 

Figure 4-21 Entrance Slit properly aligned 4-10 

Figure 5-1 Brewer Computer Display 5-1 

Figure 5-2 Tracker Cover Plate Captive-Nuts 5-2 

Figure 5-3 Tracker Azimuth Wheel Cleaning 5-2 

Figure 5-4 Tracker Over-Rotation Protection Switch 5-3 
Contents 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 iv

Document #: TBD

Version 1.0

This page intentionally left blank 
Introduction 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 1-1

Document #: TDB

Version 1.0

1 Introduction 

This Brewer Site Operators Handbook contains specific information and procedures 

required to successfully maintain the Brewer MKIV Spectrophotometer. In many 

instances, excerpts from Sci-Tech’sTM Operators Manual are used or referenced in this 

document. 

1.1 Brewer MKIV Spectrophotometer 

The Brewer Spectrophotometer is a scientific instrument which measures Ultra 

Violet, or Visible, radiation in the solar spectrum. By examining the differential 

absorption of select wavelengths in the UVB portion of the spectrum, determinations 

of Total Column Ozone (O3) and Total Column Sulphur Dioxide (SO2) are inferred. The 

MKIV instrument measures intensity of radiation in the visible part of the 

spectrum (430-450nm) and uses differential absorption in this region to infer Total 

Column Nitrogen Dioxide (NO2). 

The Brewer Spectrophotometer is core component of a complete Brewer system which 

includes the following: Spectrophotometer, Azimuth Tracker, Tripod Base, IBM 

compatible PC, and a Tractor-Feed Printer. Figure 1-1 identifies the major parts of the 

Brewer system. Figure 1-2 shows the top view the Brewer cover identifying the controls 

and features used to manipulate and calibrate the instrument. 

Figure 1-1 Complete Brewer Spectrophotometer System 
Introduction 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 1-2

Document #: TDB

Version 1.0

Figure 1-2 Top View of Brewer Enclosure 

1.2 Standard Maintenance Procedures 

In order to ensure proper operation of the Brewer Spectrophotometers, the Standard 

Maintenance Procedures (SMP) outlined in this document should be followed by the 

local site operator. Ideally, the instrument should be visited once per day but, 

realistically, a visit once or twice per week by the site operator should be sufficient in 

most cases to verify and maintain operation. Section 2 provides a condensed version of 

the SMP. Sections 3, 4, and 5 provide detailed information about the various 

procedures. 

1.3 Precautions 

• Never remove the Brewer enclosure cover during high-winds, dusty conditions, 

or when any amount of precipitation is occurring. 

• Never touch, blow-on (or even breath-on) or attempt to clean any of the Brewer’s 

internal optics (lenses, mirrors, or grading). 

• When removing the Brewer enclosures cover is required, always cover the UV 

Dome with the protective shroud provided. 

• Never set the Brewer enclosure cover on the ground or on its side where the 

cover could fall, resulting in UV Dome or Quarts Window damage. 
Introduction 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 1-3

Document #: TDB

Version 1.0

1.4 Required Tools and Supplies 

1.4.1 Tools 

Table 1-1 Required Tools 

Quantity Description Purpose 

1 5/32” x 6” Allen-Head Wrench Attach Brewer to Tracker 

Adjust Tracker Tension 

1 3/16” x 6” Allen-Head Wrench 

(**Right Angle) 

Tracker Cover Remove/Attach 

Tracker Ground Strap Attachment** 

2 9/16” Open-End Wrench Tracker Tripod Assembly/Adjustment 

1 3⁄4” Crescent Wrench General Purpose Use 

1 Medium Size Channel-Lock Pliers Loosen Military-Style Connectors 

1 1⁄4” x 8” Flat-Blade Screwdriver Tracker Leveling 

1 3⁄4” Open-End Wrench Tracker Leveling Adjustment 

1.4.2 Supplies 

Table 1-2 Required Brewer Site Supplies 

Quantity Description Purpose 

1+ Box of KemWipes or Roll of Soft 

Paper Towels 

Clean Brewer UV Dome and Quartz Window. 

Clean the Tracker Wheel and driveshaft. 

1 Bottle of Mild Glass Cleaner Clean Brewer UV Dome and Quartz Window. 

Clean the Tracker Wheel and driveshaft. 

2 Light-Weight Machine Oil Lubricate Brewer Cover Hasps. 

1 Tube of Grease Lubricate and protect Tripod Leveling Feet 

from rust. 

1 High Temperature 

Miller Stephenson 

KRYTOX GPL 200 Grease 

Lubricate the internal Micrometer. 

16 Desiccant Packs (sealed 4oz.) Placed inside Brewer Enclosure 
Introduction 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 1-4

Document #: TDB

Version 1.0

This page intentionally left blank 
Site Visit Procedures 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 2-1 

Document #: TDB

Version 1.0

2 Site Visit Procedures 

2.1 Logging Visits and Changes to the System 

Logging visits to the site and recording any changes made to the Brewer’s operation or 

configuration are extremely important to historical record of each Brewer Instrument. 

Log entries should be made both electronically and also written into the Brewer’s Log 

Book. At a minimum, make sure to log all changes and maintenance events into the 

electronic log (see Section 2.1.2). 

2.1.1 The Log Book 

Each Brewer site has a Log Book to record information about any changes to the 

operation and all maintenance activities performed on the Brewer system. 

2.1.2 Electronic Log Entries 

Electronic Log Entries are made using the Brewer Control Program CO command which 

allows the operator to enter a comment (up to 75 characters). CO comments are 

integrated into the Brewers B-File for the current date. 

1. On the Brewer Control Computer (see Figure 2-1), observe the current mode of 

operation, if the instrument is currently taking HG or UX measurements, do NOT 

interrupt the scan, wait for the scan to complete. Press the HOME key to 

terminate any measurement except HG or UX scans. 

2. Enter CO<CR> from the Brewer Main Menu. 

3. Enter the comment (up to 75 characters). Press Enter to commit the comment. If 

the comment requires more than 75 characters, the operator can issue as many 

CO commands as required to properly document the entry. Each entry is 

automatically time-stamped, so it is not necessary to include timestamp 

information in the comment text. 

4. Restore the Brewer to its automatic continuous schedule by issuing a SKC <CR> 

command. When prompted, enter EPA96D <CR> (the name of the Brewer 

schedule file). 

2.2 Daily/Weekly Maintenance Procedures 

Some of the following routine maintenance procedures, ideally; would be done on a 

daily basis, realistically; once or twice a week is all the operator may be able to 

accommodate. 
Site Visit Procedures 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 2-2 

Document #: TDB

Version 1.0

Figure 2-1 Brewer Status and Operation Indicators 

2.2.1 Brewer Computer System Checks - Daily 

1. Verify the Brewer software program is running, and that the 

system is not locked-up or in a power-saving state. 

2. Verify the Brewer date/time (see Figure 2-1) is set as close as 

possible to NIST time standard. If the site has internet access 

the NIST time page can be used as a reference (see 

http://www.time.gov/timezone.cgi?UTC/s/0/java). If the date is 

incorrect, the date can be set using the DA command. If the time is off by more 

than several seconds, the time can set manually using the TI command. Log any 

discrepancy and corrective action using the procedure described in Section 

2.1.2. 

3. Verify the Brewer is executing its continuous automatic schedule. If the Brewer is 

not executing its automatic schedule, start the schedule be issuing a SKC <CR>, 

and entering the schedule name EPA96D <CR> 

2.2.2 Brewer Checks – Daily/Weekly 

1. Verify the Brewer is tracking the Sun by observing the 

rotation of the Tracker. If the Brewer is taking an Umkehr

(UM) measurement the Brewer Quartz Window will be 

rotated perpendicular to the Sun. In all other measurement 

modes, the Brewer’s Quartz Window should be squarely 

facing the Sun and the Zenith Prism elevation should be 

tracking the Sun’s elevation. 
Site Visit Procedures 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 2-3 

Document #: TDB

Version 1.0

2. Verify Power Indicator LEDs on both the Brewer and Tracker are illuminated. 

3. Check the condition of the Humidity Monitor located 

on top of the Brewer Enclosure between Filter Wheel 

#1 and the Entrance Slit View Tube. The Humidity 

Indicator’s circles change color from blue to pink if 

the humidity has reached specified levels (see Figure 

2-2). If the Humidity inside the Brewer is greater than 

20%, follow the Desiccant Pack Replacement 

Procedure defined in Section 4.4. Make log entries 

noting the humidity indication and any desiccant 

changes. 

Figure 2-2 Humidity 

Indicator 

4. Check and log the condition (clean, dirty) of the UV Dome and Quartz Window 

(see Section 4.1). Clean the UV Dome and Quartz Window using paper towels 

and glass cleaner. 

5. If the intensity of the Sun is bright enough to cast shadows, perform the Sun 

Sighting Procedure defined in Section 4.5. This procedure should be done once 

a week. Log the Old/New Horizon and North Correction results of the Sun 

Sighting in the electronic log and also in the site Log Book. 

2.2.3 Tracker Checks – Bi-Monthly 

Regular maintenance on the Tracker is vital to the proper 

operation of the Brewer. 

 

1. Run the Steps per Revolution Test by issuing a SR <CR> 

command. After the test completes, record the number 

returned by the test in the log book and electronic log. 

2. Inspect and clean the Tracker’s aluminum azimuth wheel and stainless steel 

drive shaft using the procedures defined in Section 5. Even if no slippage is 

observed in the SR test, the wheel and drive shaft should be cleaned at least 

once a month. Record the maintenance actions in the site log book and 

electronic log. 

If Tracker slippage is not due to dirty drive mechanism, then azimuth drive 

mechanism tensions should be checked. Contact Patrick.Disterhoft@noaa.gov if 

slippage due to drive tension is suspected.
Site Visit Procedures 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 2-4 

Document #: TDB

Version 1.0

This page intentionally left blank 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-1

Document #: TBD

Version 1.0

3 Brewer Control Computer 

A Brewer Spectrophotometer requires an external DOS/Windows based Personal 

Computer (PC) to operate. The Brewer Software is written in GWBasic, and runs in a 

DOS Shell on most versions of the Windows operating system. The Control Computer 

provides the following functions: 

• Controls the Brewer Spectrophotometer, stores Brewer data. 

• Provides remote access/control of the Brewer, and transfer of Brewer data. 

• Connects to internet or dial-up NIST time sources to keep PC internal clock 

accurate. 

This remainder of this section describes the control computer’s hardware configuration 

and gives an overview of the installed software packages. The software configuration of 

the control computer is adapted to suit a particular site’s internet connectivity 

capabilities. 

3.1 Hardware Configuration 

Brewer sites may or may not have internet connectivity. Brewer Sites that do have 

internet access use an Ethernet NIC to connect to the existing network infrastructure. 

Sites that do not have internet access use a dial-up phone line and modem for data 

access and control. Other than the standard PC components and peripherals, Table 

3-1 outlines the hardware options required for internet and non-internet Brewer sites. 

Table 3-1 Hardware Configuration 

Hardware Specification Internet No Internet 

RS-232 Serial Communication Port Required Required 

Printer Parallel Port (if Printer is installed) Required Required 

Ethernet Network Interface Card Required Optional 

Internal Modem Card or; 

Second available RS-232 Serial port and External Modem 

Optional Required 

3.2 Windows Software Configuration 

This section describes the various software packages installed on the Brewer Control 

PC if the operating system is Windows 98. The software package configuration depends 

on the site’s internet connectivity. If the site does have an internet connection, specific 

packages will be enabled, while others may still be installed but not enabled. Table 3-2

shows the software configurations for Brewer sites with and without internet 

connectivity. 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-2

Document #: TBD

Version 1.0

Table 3-2 Software Configuration 

Package Name Purpose Internet No Internet 

Windows 98 Operating System Req Req 

Brewer Software Runs the Spectrophotometer Req Req 

pcAnywhere Provides remote access/control and data transfer Req Req 

NIST Time Automatically sets time via Internet Req Opt 

PC Clock Sets time via modem Opt Req 

Auto-Reboot Reboots the PC on a specified schedule Opt Opt 

Uptime Monitor Logs Uptime and downtime of the PC Opt Opt 

Macro Scheduler Stops/Starts Brewer and PC Clock Software Opt Req 

3.2.1 PC Operating System 

The Brewer Control Computer is using Windows 98 as its operating system. The 

required programs have been added to Startup menu, and load automatically when 

Windows boots. The Icons for the programs will appear in the Windows Task Bar 

located to the bottom of the screen as shown in Figure 3-1. 

Figure 3-1 Windows Task Bar on Brewer PC with Internet Connectivity 

3.2.2 PC Brewer Software 

The Brewer Software is written in GWBasic and runs in a DOS shell. The program files 

are installed in the C:\brewer subdirectory, and the Brewer data files are stored in the 

C:\bdata subdirectory. The Brewer program is automatically loaded at boot-time by 

placing a short-cut to C:\brewer\brewer.bat in the Windows Startup Folder. For 

more information about the Brewer Software, consult the Brewer Operators Guide. For 

quick reference purposes, the major control and monitoring features of the Brewer 

Software are identified in Figure 3-2. 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-3

Document #: TBD

Version 1.0

Figure 3-2 Brewer Software Display Information 

3.2.3 PC Remote Control Software 

Remote Control of the Brewer PC and data transfer is accomplished via pcAnywhere

Remote Control Software. The Brewer PC is configured to be a pcAnywhere Host, and 

depending on the site’s internet capabilities, will be configured to use TCP/IP 

communications, or configured to use a modem/phone-line if no internet connection 

exists. The pcAnywhere Host program is automatically loaded at boot-time by placing 

a short-cut to the host configuration file (C:\windows\desktop\BR###.BHF) in the 

Windows Startup folder. When the pcAnywhere Host program is running, an icon 

resides on the Windows Task Bar at the bottom of the screen (see Figure 3-1). 

3.2.4 PC Time-Keeping Software 

The Brewer software requires accurate Universal time to properly calculate where the 

Sun is supposed to be during the day. One of two programs is used to keep the PC 

system time in sync with the NIST Time Standard. The first, NIST Time is used at 

Brewer sites that do have internet connectivity. The second, PC Clock is used at Brewer 

sites that do not have access to the internet. More information about each of these two 

programs can be found in the following sections. 

3.2.4.1 NIST Time Program 

The NIST Time software is installed in C:\NIST Time and is automatically loaded at 

boot time by a short-cut to C:\NIST Time\nistimew.exe being placed in the 

Windows Startup folder. Once the program’s options are initially configured, no other 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-4

Document #: TBD

Version 1.0

actions are required. An example screen capture of the NIST Time Program Screen is 

show in Figure 3-3. 

Figure 3-3 NIST Time Client Window 

3.2.4.2 PC Clock Program 

PC Clock software is used to keep the Brewer PC’s clock in sync with the NIST Time 

standard via dial-out modem. PC Clock is for use at Brewer sites that do not have direct 

internet access. PC Clock is installed in C:\pcclock subdirectory. Unlike other 

programs on the Brewer PC, PC Clock is not loaded at boot-time, and must be 

executed programmatically through a scheduling program called Macro Scheduler. See 

Section 3.2.7 for more information about Macro Scheduler. 

Brewer sites that do not have internet access must share the modem line connection for 

all communications activities including pcAnywhere Remote Control, data transfer, and 

dial-out time synchronization. Normally, each Brewer site only has one available phone 

line for modem use, and pcAnywhere must have control of the modem for remote 

access and data transfer. Under these circumstances, a problem comes to surface with 

resource contention for the modem. The solution to this problem is to use the Macro 

Scheduler program to periodically end pcAnywhere and give control of the modem to 

PC Clock. The scheduler then instructs PC Clock to connect to NIST and synchronize 

the time by executing C:\pcclock\pcclock.exe /A (automatic option). After PC 

Clock time synchronization has finished, the scheduler then restarts pcAnywhere for 

normal operations. 

When PC Clock is executing, a Window is opened screen similar to the one shown in 

Figure 3-4. PC Clock has been pre-configured and should not require any user 

interaction. However, in event the parameters get corrupted, the user can start PC 

Clock manually and press F11 to activate the PC Clock configuration Screen (see 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-5

Document #: TBD

Version 1.0

Figure 3-5). The user can then use the arrow keys to re-enter the parameters and save 

them by pressing Enter. 

Figure 3-4 PC Clock Program Window 

Figure 3-5 PC Clock Configuration Screen 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-6

Document #: TBD

Version 1.0

3.2.5 PC Automatic Reboot 

Since the Brewer’s run continuously and for the 

most-part unattended, the ability for the PC to 

reboot itself on a regular basis is desirable. The 

software that makes this automatic reboots 

possible is called WinOFF. The WinOFF

installation program installs into the 

C:\Program Files\WinOFF subdirectory. 

This utility loads itself onto the Windows System 

Tray, and loads automatically at boot-time (no 

Startup short-cut required). A (optional) clock showing the time of the next scheduled 

reboot is shown in the lower right of the Desktop (see Figure 3-6). The WinOFF

configuration screen is activated by right-clicking on the reboot clock and selecting 

Configuration. The options that are critical to correct operation are high-lighted in 

orange in Figure 3-7 and Figure 3-8. 

Figure 3-6 WinOFF Reboot Clock 

Figure 3-7 WinOFF Shut down programming Screen 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-7

Document #: TBD

Version 1.0

Figure 3-8 WinOFF Options Screen 

3.2.6 PC System Uptime Monitor 

The System Uptime Monitor is a utility that logs when the system reboots or 

experiences a power outage. The duration of power outages is logged as well as how 

log the system has been running for since its last reboot or power failure. The logged 

outages are displayed in a text window as shown in Figure 3-9. Uptime Monitor is 

installed in the C:\uptimemonitor subdirectory. Uptime Monitor is loaded at boottime by placing a short-cut to the executable in the Windows Startup folder. 

3.2.7 PC Scheduling Software 

Brewer PC local automated program control and scheduling are required when a 

Brewer site does not have internet access, and its only means of communication is via 

modem link. Under these circumstances, a program called Macro Scheduler (see 

Figure 3-10) is installed to automatically stop the pcAnywhere Host program, open PC 

Clock to dial NIST and update Brewer PC’s clock with current Universal Time, and 

finally restart the pcAnywhere Host program. 

The Macro Scheduler installation program places the executable in the standard 

Program Files folder. Macro Scheduler is loaded at boot-time by a short-cut being 

placed in the Windows Startup folder. When Macro Scheduler is running, a Cog-Icon is 

placed in the System Tray. 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-8

Document #: TBD

Version 1.0

Figure 3-9 System Uptime Monitor Screen 

Figure 3-10 Macro Scheduler Software 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-9

Document #: TBD

Version 1.0

3.3 Brewer-to-PC Communications Interface 

The Brewer Spectrophotometer communicates with the control PC via RS-232 serial 

communications link. If the distance between the Brewer and PC is more than 25 feet, 

a RS-485 converter is used to increase data transmission capabilities over longer cable 

lengths. 

3.3.1 RS-232 

Each Brewer Instrument has a RS-485 converter installed inside the chassis. When the 

Brewer is configured for RS-232 communications, the RS-485 converter is by-passed 

by reconfiguring the wiring harness connected to the RS-485 converter as shown in 

Figure 3-11. 

To enable the RS-485 Converter, the cable (socket connector) with the red, orange, and 

black wires is connected to J2 on the Brewer Computer CPU card. The socket 

originally connected to J2 on the CPU card is connected to the plug that connects to the 

units’ four-position terminal block as shown in Figure 3-12

Cable connection to J2 on the CPU 

card by-passes the RS-285 converter. 

(View of 10-pin connection to CPU-J2 

blocked by ribbon cable). 

For RS-232 operation, this 

cable connection by-passes 

the RS-485 converter.

ICC-11 

RS-232 to RS-485 

Converter 

Figure 3-11 RS-485 Converter By-Passed in Brewer Chassis

 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-10

Document #: TBD

Version 1.0

10-pin Socket Connector 

removed from CPU J2 and 

connected to 4-wire cable 

J2 Connector on CPU Card

Figure 3-12 RS-485 Converter Connected in the Brewer Chassis 

3.3.2 RS-485 Converters 

3.3.2.1 ICC-11 RS-232-RS485 Converter 

If an ICC-11 is used inside the Brewer Chassis, it draws its power from the DB-25F 

connecter. The required RS-232 hand-shaking signals are looped-back to the ICC-11 

via the DB-25F connector. See Figure 3-13 for the wiring diagram of the ICC-11. 

If an ICC-11 is connected to the Brewer Control Computer, the ICC-11 will require an 

external 9 VDC power supply. Depending on the serial port configuration of the Control 

Computer, gender changers and/or DB-25 to DE-9 adapters may be required to 

interface the serial port. See Figure 3-13 for the wiring connections required at the 

Control Computer. 

3.3.2.2 IC-485s RS-232-RS-485 Converter 

If an IC-485s is used inside the Brewer Chassis, it draws its power from the DB-25F 

connecter. The required RS-232 hand-shaking signals are looped-back to the IC-485s 

via the DB-25F connector. See Figure 3-14 for the wiring diagram of the IC-485s. 

If an IC-485s is connected to the Brewer Control Computer, the IC-485s will require an 

external 9 VDC power supply. Depending on the serial port configuration of the Control 

Computer, gender changers and/or DB-25 to DE-9 adapters may be required to 

interface with the PC serial port. See Figure 3-14 for the wiring connections required at 

the Control Computer. The IC-485s requires the use of a hand-shaking loop-back 

adapter as shown in Figure 3-14. 
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-11

Document #: TBD

Version 1.0

BREWER CPU

Figure 3-13 ICC-11 RS-485 Converter Wiring Diagram 

4

32

1

Tx

SIM DCE

MON DTE

32

10

J2

P2

RED

ORANGE

BLACK

TXRX

DB-25M

5682379

WHITE

GND

J101DATA I/O

RR+

TT+

BLACKREDWHITEORANGE

2

9

3

10 J

B

I

C

BLACKREDWHITEORANGE

RS232-RS485 CONVERTER

ICC-11

CABLE ASSEMBLY

BREWER GND

BREWER +15Vdc

BLACK

RED

BREWER MARK IV SPECTROPHOTOMETER CHASSIS

RR+

TT+

P101

JB

I

C

WHITEBLACKWHITEBROWN

WHITEBROWNWHITEBLACK

OPTIONALDB-25M toDE-9FADAPTER

BREWERHOSTCOMPUTER

RS-232SERIALPORT

DB-25M

CABLE

ASSEMBLY

CABLE

ASSEMBLY

TWISTED

PAIRS

CABLESHIELD

1 2

3

Rx

PWR

DB-25M

ICC-11

RS232-RS485 CONVERTER

5682379

4

32

1

PWR

Rx

3

2 1

MON DTE

SIM DCE

Tx

10-PinHEADER.1" Cen

AMPAMPMODU MTConnectorpn: 102398-3MOLEXpn:22-55-2101 

AMPAMPMODU MTConnectorpn: 102398-3MOLEXpn:22-55-2101 

25-PIN

GENGER

CHANGER

F to F
Brewer Control Computer 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 3-12

Document #: TBD

Version 1.0

AMPAMPMODU MTConnectorpn: 102398-3MOLEXpn:22-55-2101 

10-PinHEADER.1" Cen

AMPAMPMODU MTConnectorpn: 102398-3MOLEXpn:22-55-2101 

Figure 3-14 IC-485s RS-485 Converter Wiring Diagram M to M GENGER CHANGER 25-PIN REQUIRED MODIFIED SURGE PROTECTOR WITH FORCED HANDSHAKING

BREWER CPU

12

OPTIONALDB-25M toDE-9FADAPTER

BREWERHOSTCOMPUTER

RS-232SERIALPORT

DB-25FDB-25F

CABLE

ASSEMBLY

CABLE

ASSEMBLY

TWISTED

PAIRS

CABLESHIELD

34

DTE

DCE

MON

T/R-ON

T-RTS

R-ON

R-RTS

T-RTS

32

10

J2

P2

RED

ORANGE

BLACK

TXRX

DB-25M

5682379

WHITE

GND

J101

DATA I/O

T+TRR+

ORANGEWHITEBLACKRED

392

10

C

I

JB

ORANGEWHITEBLACKRED

RS232-RS485 CONVERTER

IC-485s

CABLE ASSEMBLY

BREWER GND

BREWER +15Vdc

BLACK

RED

BREWER MARK IV SPECTROPHOTOMETER CHASSIS

IC-485s

RS232-RS485 CONVERTER T+T- RR+

5682379 T-RTS

R-RTS

R-ON

T-RTS

T/R-ON

MON

DCE

DTE

1234

C

I

JB

BROWNWHITEWHITEBLACK

BLACKWHITEWHITEBROWN

P101
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-1

Document #: TBD

Version 1.0

4 Brewer Spectrophotometer Maintenance 

The day-to-day maintenance of the Brewer Spectrophotometer is fairly straight forward. 

The routine procedures include visual inspections and cleaning, checking humidity 

levels inside the case, changing desiccant bags as required, and periodically calibrating 

the instrument’s tracking with a Sun Sighting Alignment. This section describes each of 

these tasks. 

4.1 Cleaning External UV Dome and Quartz Window 

For optimal accuracy, the UV 

Dome and Quarts Window should 

be kept free of dust and water 

spots. Using a mild window or 

glass cleaner such and Windex 

and paper towels, clean the UV 

Dome, Quarts Window and 

Viewing Window as shown in 

UV Dome 

Viewing Window 

Figure 4-1. Note any 

condensation inside the glass. 

Log the condition of the glass 

surfaces and the cleaning in the 

electronic log and site log book. 

Quartz Window 

Figure 4-1 Brewer Routine Glass Cleaning 

4.2 Enclosure Cover Removal and Maintenance 

Before removing the Brewer enclosure cover, 

always install the UV Dome Protector as shown in 

Figure 4-2. To remove the cover, rotate (CCW) 

the handle on each of the four latches, after the 

latch has been lifted away from the catch, rotate 

the latch handle (CW) to the tightened position 

(see Figure 4-4). This will prevent the latches from 

snagging on the catch when the cover is lifted. 

Lift the cover straight up, keeping the cover level. 

Once the cover has been removed, examine the 

weather strip on the inside of the cover. Make 

sure the weather stripping is seated properly as shown in 

UV Dome Protector 

Figure 4-3. Place the cover 

flat on the ground (preferably on a clean dry surface) so that it can not tip over. If the 

latches are hard to turn, apply a drop of light-weight machine oil to each of the latches 

as shown in 

Figure 4-2 UV Dome Protector 

Figure 4-4. 
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-2

Document #: TBD

Version 1.0

 Lubricate Latch 

with one drop of 

light machine oil

Weather Seal 

Properly Seated 

Around Entire 

Perimeter of Cover 

Figure 4-3 Inside Cover Weather-Seal Figure 4-4 Latch Maintenance 

4.3 Checking Humidity Indicators 

Humidity is the enemy of the Brewer. 

Prolonged exposure to elevated 

humidity levels (greater than 20%) 

inside the Brewer enclosure may 

degrade performance or cause serious 

damage the mechanics and optics. 

The Brewer enclosure has a Humidity 

Monitor mounted in the Viewing 

Window that should be checked several 

times a week (see 

Humidity Monitor 

Spectrometer 

Figure 4-5). Other 

indicators of humidity include the 

Breather Tube located inside the 

Brewer enclosure (see 

Humidity 

Indicator 

Breather Tube 

Figure 4-7), and 

the Spectrometer Humidity Indicator mounted on the side of spectrometer case (see 

Figure 4-5 Humidity Indicator Locations 

Figure 4-8). The Breather Tube and Spectrometer Humidity Indicators should be 

checked when ever there is a need to remove the cover from the Brewer for routine 

maintenance. 

4.3.1 Humidity Monitor Strip 

The Humidity Monitor is visible through the 

Viewing Window between Filter Wheel #1 and 

the Entrance Slit View Tube. The Humidity 

Indicator’s circles change color from Blue to 

Lavender if the humidity has reached specified 

levels (see Figure 4-6). If the Humidity inside 

the Brewer is greater than 20%, follow the 

Desiccant Pack Replacement Procedure 

defined in Section 4.4.1. Make log entries 

noting the humidity indication and any desiccant 

changes. Figure 4-6 Humidity Monitor Strip 
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-3

Document #: TBD

Version 1.0

4.3.2 Breather Tube Desiccant 

The breather tube vents the Brewer 

enclosure to the outside atmosphere. 

The desiccant in the breather tube is 

intended to remove moisture from air 

drawn into the enclosure by changes in 

barometric pressure. The desiccant 

beads inside the breather tub should be 

dark blue as shown in 

Breather Tube 

Figure 4-7. If the 

beads start to turn pink, the breather 

tube should be replaced with a freshly 

dried breather tube. Breather Tube 

replacement procedure is defined in 

Section Figure 4-7 Breather Tube Desiccant 4.4.2. 

4.3.3 Spectrometer Humidity Indicator 

The intent of the Spectrometer Humidity 

Indicator (see Figure 4-8) is to keep the 

moisture level down in the spectrometer 

compartment. The indicator is also a 

desiccant holder. Under normal 

circumstances, maintenance of this 

indicator will be done by NOAA service 

personnel during scheduled 

spectrophotometer calibrations. 

Figure 4-8 Spectrometer Humidity Indicator 

4.4 Desiccants 

4.4.1 Changing Desiccant Packs 

Reusable desiccant packs are placed inside the Brewer chassis. Six to eight packs may 

be used, depending on the environment where the Brewer is located. The packs should 

not obstruct the view of any optics and should be placed away from moving parts such 

as gears. The preferred location for desiccant packs is shown in Figure 4-9. 

Replacement desiccant packs must be stored in an air-tight container such as a ZipLock bag. The desiccant packs removed from the Brewer should not be discarded

and should be stored in an air-tight Zip-Lock bag. Fresh supplies of desiccant packs will 

be provided by NOAA personnel during scheduled calibration visits. 
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-4

Document #: TBD

Version 1.0

Packs 4 & 5 

Packs 1,2,3 

Packs 6 & 7 

Pack 8 

Figure 4-9 Desiccant Pack Locations 

4.4.2 Changing Breather Tube Desiccant 

To replace the breather tube, remove the tube from the mounting brackets, and 

unscrew the breather tube from the vent hose. Connect the vent hose to the 

replacement breather tube and secure the breather tube in the mounting brackets. Note 

the replacement activity in the electronic log and site log book. 

4.5 Sun Sighting Alignment 

Accurate measurements depend on the instrument being aligned very accurately to the 

Sun. Improper alignment, inaccurate computer clock, or inaccurate latitude/longitude, 

can affect polarization and the consistency of all measurements. This procedure 

assumes the Brewer’s Tracker has been properly aligned towards North and accurately 

leveled during the installation process. 

4.5.1 Procedure 

This sun sighting procedure can only be done on a day 

when the intensity of sun light causes sharp shadow cast. 
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-5

Document #: TBD

Version 1.0

1. Verify the date and the time on the Brewer Control Computer is set as close as 

possible to the NIST time standard. Brewer sites that have internet access will 

have a NIST time program that should keep the time set very accurately. 

2. On the Brewer Control Computer (see Figure 4-10), observe the current mode of 

operation, if the instrument is currently taking HG or UX measurements, do NOT 

interrupt the scan, wait for the scan to complete. Press the HOME key to 

terminate any measurement except HG or UX scans. 

Figure 4-10 Brewer Computer Display 

3. Zero the Azimuth Tracker by issuing an AZ command. This will cause the tracker 

to rotate to its zero position (North), and then repositions to track the Sun. 

4. Zero the Zenith Prism by issuing a ZE command. 

5. Enter Sun Sighting mode by issuing a SI command. The following screen is 

displayed (see Figure 4-11). At this time, the operator should proceed outside to 

the Brewer instrument. 
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-6

Document #: TBD

Version 1.0

Jun 08/06 day= 159 o3 #132 * Boulder C.U.T. E 22:45:31 UGA2b 

 Si -- 2136672540 Bytes in: * out: 47.56 

 Keyboard Sighting 

 Press :- 

 Crsr up to raise zenith 

 Crsr down to lower zenith 

 Crsr right for azimuth clockwise 

 Crsr left for azimuth counterclockwise 

 Press CTRL-END when finished 

 Press K for keyboard 

 Press R for remote 

REMOTE Horizontal correction: 

 Step= 5 Old = 7 ;New = 7 

 North correction: 

 Old = 55 ;New = 55 

Figure 4-11 Brewer SI Command Screen 

The Brewer has two sighting tubes located on top of the instrument. The Iris View Tube 

is used to make course adjustments to the Sun tracking alignment. The Entrance Slit 

Tube is used to make fine adjustments to the Sun tracking alignment. Figure 4-12

depicts how light enters the Brewer and projects onto the Iris and Entrance Slit Plate. 

The objective of the alignment procedure is to have the beam of light pass directly 

through the center of the Iris opening, and have the entrance slit centered horizontally 

and vertically within the beam of light. 

Figure 4-12 Overview of the Brewer Sun Sighting Mechanism

In some instances, the Brewer’s alignment may be so far out of tolerance that no image 

of the Sun is visible in the Iris View Tube. In this case, the operator should employ a 

manual sighting technique that uses the Brewer’s enclosure shape to cast a shadow 

next to the Quartz Window (refer to Figure 4-13). 
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-7

Document #: TBD

Version 1.0

• Press and hold the Brewer’s Azimuth CW (clockwise) button. The tracker will 

begin to rotate in small increments. Observe the corner of the Brewer enclosure 

to the right of the Quartz Window. Continue to hold the CW button until a shadow 

appears next to the Quarts Window as shown in Figure 4-13. 

• Press and release the CCW button until brewer rotates counter-clockwise just 

enough to make the shadow disappear (similar to Figure 4-14). 

Look down through the Iris View Tube (as shown in Figure 4-16) being careful not to 

block the sun from the Quartz Window with your shoulder. Use the Zenith UP/DOWN 

Buttons to attempt to position an image of the Sun on the Iris (see Figure 4-18). 

The Zenith Prism shaft having finite rotation limits (see Figure 4-15) can be damaged if 

the operator attempts to rotate the Zenith Prism beyond these limits (-90o to 180o). To 

prevent possible damage to the Brewer, never manually rotate the Zenith Prism beyond 

0o to 90o. Once the Sun’s image is visible on the Iris proceed to step 8. 

No Shadow

indicates Brewer

azimuth 

alignment is 

close, provided 

the tracker 

azimuth has just 

been rotated 

CCW after 

observing a 

shadow. 

Shadow

cast by

corner of 

Brewer 

enclosure 

Figure 4-13 Visible shadow caused by

Brewer's azimuth alignment being rotated too 

far in the clockwise (CW) direction

Figure 4-14 Brewer with proper azimuth 

alignment. No shadow may also indicate 

azimuth is rotated too far in the counterclockwise (CCW) direction
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-8

Document #: TBD

Version 1.0

Figure 4-15 Zenith Prism Maximum Rotations 

6. Position your body to the right of the Quartz Window, look through the Iris View 

Tube as shown in Figure 4-16. Make sure not to block the sun from the Quartz 

Window. 

7. Press the UP/DOWN buttons to move the Zenith Prism, press the CC (clockwise) and CCW (counter clock-wise) buttons to rotate the Tracker. See Figure 

4-17 for the orientation of the UP/DOWN and CC/CCW buttons. 

If the course-sighting of the instrument is slightly off, the image of the Sun would 

be projected on the face of the Iris and shown in Figure 4-18. Figure 4-19 shows 

the image of the Sun properly centered on the opening of the Iris. When the Sun 

is passing directly through the center of the Iris, there may be a slight orah of 

light surrounding the Iris opening, or there may be no visible indication of light. 

 

8. Once the course sighting is completed, look down through the Entrance Slit View 

Tube (the right view tube on top of the Brewer). Once again, be very careful to 

position your body to the right of the Quartz Window so your shoulder does not 

block light from entering the Zenith Prism. If the alignment of the instrument is 

only slightly off, you would see an image similar to the one shown in Figure 4-20. 

Use the UP/DOWN and CC/CCW buttons move the slit to the horizontal and 

vertical center of the circle of light and shown in Figure 4-21. 
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-9

Document #: TBD

Version 1.0

Figure 4-16 Looking through sighting tubes without blocking the Quartz Window from the 

Sun 

Figure 4-17 Locations of Tracker 

Sighting Adjustment Buttons 

Figure 4-18 Image of Sun 

improperly aligned on the 

on face of the Iris 

Figure 4-19 Image of Sun 

properly aligned on the face 

of the Iris 

Quartz 

Window 

Zenith 

Prism 

Elevation and 

Azimuth 

Adjustment 

Buttons 

Zenith Azimuth 

UP CW 

DOWN CCW 

 
Brewer Spectrophotometer Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 4-10

Document #: TBD

Version 1.0

Figure 4-20 Entrance Slit 

improperly aligned 

Figure 4-21 Entrance Slit 

properly aligned 

9. Return to the Brewer Control Computer and press CTRL-END to end the Sun 

Sighting mode. Press Y to enter the new Horizontal and North Correction values. 

10. Restore the Brewer to its automatic continuous schedule by issuing a SKC <CR> 

command. When prompted, enter EPA96D <CR> (the name of the Brewer 

schedule file). 

4.5.2 Sun Sighting Troubleshooting 

Symptom Indication of Problem With... 

North Correction numbers alternate 

between higher and lower numbers 

consistently from morning to afternoon. 

Tracker may not be leveled Correctly. Or it 

may indicate a problem with the 

instrument, Tracker, or Optical Circuit 

Board. 

Very inconsistent North Correction values 

from one sighting to another. 

Tracker drive mechanism may be slipping. 

Inconsistent Horizon Correction values. Possible Zenith Prism slippage. 

Constant drift in both Horizon and North 

corrections. 

Site Latitude and/or Longitude coordinates 

are incorrect. Or the computer’s date or 

time may not be set correctly. 
Azimuth Tracker Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 5-1

Document #: TBD

Version 1.0

5 Azimuth Tracker Maintenance 

5.1 Tracker Mechanical Inspection 

The Tracker/Tripod assembly should be inspected visually for mechanical integrity. 

• Verify the tripod is securely fastened to the concrete slab. 

• Check for loose nuts/bolts where the Tracker is bolted to the tripod. 

• Verify that all four of the brewer head bolts are not loose or missing. 

• Check the power and communication interface cables for signs of stress, binding, 

and serious deterioration. 

• Verify that all military-style connectors are tightened (finger tight). 

Correct any mechanical problems and log actions in the electronic log and site log book. 

If cables are damaged significantly, contact Patrick.Disterhoft@noaa.gov for further 

assistance. 

5.2 Tracker Azimuth Wheel Maintenance 

The Tracker’s azimuth wheel requires periodic cleaning to keep the Brewer accurately 

tracking the Sun. The azimuth wheel is driven by a friction coupling to a drive shaft. 

Over time, the wheel and the shaft become dirty and slippage occurs. To clean the 

azimuth wheel, follow the procedure below: 

1. On the Brewer Control Computer (see Figure 5-1), observe the current mode of 

operation, if the instrument is currently taking HG or UX measurements, do NOT 

interrupt the scan, wait for the scan to complete. Press the HOME key to 

terminate any measurement except HG or UX scans. 

Figure 5-1 Brewer Computer Display 
Azimuth Tracker Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 5-2

Document #: TBD

Version 1.0

2. Proceed out the Brewer instrument. Turn off power to the Tracker by pressing 

the power button on the lower side of the Tracker. The power to the Brewer 

Spectrophotometer can remain on. 

3. Remove the Tracker’s cover 

panel(s) by removing four 5/32” 

hex-head bolts. When the 

tracker’s cover is removed, check 

the four captive-nuts in the inside 

of the panel (see Figure 5-2). 

Rotate the captive-nuts (CW) until 

they rotate freely and base of the 

hex-head bolts. This will ensure 

that the captive-nuts do not bind 

against the Tracker housing when 

the cover is re-attached. 

Captive-Nut 

(one of four) 

4. To clean the entire azimuth wheel the Tracker will need to be rotated manually. 

Before continuing, note the relative orientation of the Tracker’s azimuth, use this 

position as a reference-marker. Return the Tracker to this position once the 

cleaning is completed. The Tracker should be able to be manually rotated up to 

180

Figure 5-2 Tracker Cover Plate Captive-Nuts 

o

 left or right from the current azimuth. If the Tracker is rotated too far in one 

direction, the tension cable on the Over-Rotation Protection Switch will trip the 

internal toggle switch (see Section 5.3 for information about the Over-Rotation 

Protection Switch). 

5. Using a paper towel and mild 

cleaner such as Formula 409

or Windex, clean the edge of 

the full circumference of the 

aluminum azimuth wheel and 

stainless steel drive shaft as 

shown in Figure 5-3. The 

edge of the wheel and shaft 

should be smooth and shiny 

after cleaning is completed. Clean the edge of the 

aluminum Azimuth Wheel 

and the base of stainless 

steel Drive Shaft

6. Manually rotate the tracker to 

its original azimuth position. 

Install Tracker cover panels, 

and press the Power button to 

restore power the Tracker. 

Figure 5-3 Tracker Azimuth Wheel Cleaning 
Azimuth Tracker Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 5-3

Document #: TBD

Version 1.0

7. Return to the Brewer Control Computer. Zero the Azimuth Tracker by issuing an 

AZ command. This will cause the tracker to rotate to its zero position (North), and 

then repositions to track the Sun. 

8. Restore the Brewer to its automatic continuous schedule by issuing a SKC <CR> 

command. When prompted, enter EPA96D <CR> (the name of the Brewer 

schedule file). 

5.3 Tracker Over-Rotation Protection Switch 

Under certain circumstances such as a power-outage or brown-out, the Brewer can lose 

track of where it thinks the azimuth wheel is positioned. The Tracker Over-Rotation 

Protection Switch prevents the Brewer from damaging cables due cable binding. Inside 

the Tracker housing, a toggle switch is mounted on a fixed bracket. A cable attaches 

the Trackers center axle to the toggle switch lever. If the axle rotates too far the tension 

on the cable will flip the toggle switch which in turn kills power to the tracker. 

During routing Tracker maintenance, the connections of the cable linking the Tracker 

Axle to the Over-Rotation switch should be inspected. The cable is connected to the 

toggle switch with fishing line. It is feasible for the knot in the fishing line to come 

undone. Figure 5-4 depicts how the tension wire connects to the Over-Rotation 

Protection Switch, and the switch in its normal (operational) position. 

10 lb. Fishing Line 

Connecting Switch to 

Tension Cable

Over-Rotation Kill 

Switch (shown in 

the normal position)

Tension Cable Attached to 

Tracker Axle Via Hose Clamp.

Figure 5-4 Tracker Over-Rotation Protection Switch 
Azimuth Tracker Maintenance 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 5-4

Document #: TBD

Version 1.0

This page intentionally left blank 
Appendix A 

Day of Year Calendar 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 A-1 

Document #: TDB

Version 1.0

Day of Year Calendar (Perpetual) 

Day JAN 

1 

FEB 

2 

MAR 

3 

APR 

4 

MAY

5 

JUN

6 

JUL

7 

AUG

8 

SEP

9 

OCT 

10 

NOV 

11 

DEC

12 Day

1 001 032 060 091 121 152 182 213 244 274 305 335 1 

2 002 033 061 092 122 153 183 214 245 275 306 336 2 

3 003 034 062 093 123 154 184 215 246 276 307 337 3 

4 004 035 063 094 124 155 185 216 247 277 308 338 4 

5 005 036 064 095 125 156 186 217 248 278 309 339 5 

6 006 037 065 096 126 157 187 218 249 279 310 340 6 

7 007 038 066 097 127 158 188 219 250 280 311 341 7 

8 008 039 067 098 128 159 189 220 251 281 312 342 8 

9 009 040 068 099 129 160 190 221 252 282 313 343 9 

10 010 041 069 100 130 161 191 222 253 283 314 344 10 

11 011 042 070 101 131 162 192 223 254 284 315 345 11 

12 012 043 071 102 132 163 193 224 255 285 316 346 12 

13 013 044 072 103 133 164 194 225 256 286 317 347 13 

14 014 045 073 104 134 165 195 226 257 287 318 348 14 

15 015 046 074 105 135 166 196 227 258 288 319 349 15 

16 016 047 075 106 136 167 197 228 259 289 320 350 16 

17 017 048 076 107 137 168 198 229 260 290 321 351 17 

18 018 049 077 108 138 169 199 230 261 291 322 352 18 

19 019 050 078 109 139 170 200 231 262 292 323 353 19 

20 020 051 079 110 140 171 201 232 263 293 324 354 20 

21 021 052 080 111 141 172 202 233 264 294 325 355 21 

22 022 053 081 112 142 173 203 234 265 295 326 356 22 

23 023 054 082 113 143 174 204 235 266 296 327 357 23 

24 024 055 083 114 144 175 205 236 267 297 328 358 24 

25 025 056 084 115 145 176 206 237 268 298 329 359 25 

26 026 057 085 116 146 177 207 238 269 299 330 360 26 

27 027 058 086 117 147 178 208 239 270 300 331 361 27 

28 028 059 087 118 148 179 209 240 271 301 332 362 28 

29 029 088 119 149 180 210 241 272 302 333 363 29 

30 030 089 120 150 181 211 242 273 303 334 364 30 

31 031 090 151 212 243 304 365 31 

Day JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC DAY
Appendix A 

Day of Year Calendar 

NOAA/EPA Brewer Network

Site Operators Handbook

NOAA/ESRL/GMD Issuance 

June 8, 2006 A-2 

Document #: TDB

Version 1.0

Day of Year Calendar (Leap Years) 

Day JAN 

1 

FEB 

2 

MAR 

3 

APR 

4 

MAY

5 

JUN

6 

JUL

7 

AUG

8 

SEP

9 

OCT 

10 

NOV 

11 

DEC

12 Day

1 001 032 061 092 122 153 183 214 245 275 306 336 1 

2 002 033 062 093 123 154 184 215 246 276 307 337 2 

3 003 034 063 094 124 155 185 216 247 277 308 338 3 

4 004 035 064 095 125 156 186 217 248 278 309 339 4 

5 005 036 065 096 126 157 187 218 249 279 310 340 5 

6 006 037 066 097 127 158 188 219 250 280 311 341 6 

7 007 038 067 098 128 159 189 220 251 281 312 342 7 

8 008 039 068 099 129 160 180 221 252 282 313 343 8 

9 009 040 069 100 130 161 191 222 253 283 314 344 9 

10 010 041 080 101 131 162 192 223 254 284 315 345 10 

11 011 042 071 102 132 163 193 224 255 285 316 346 11 

12 012 043 072 103 133 164 194 225 256 286 317 347 12 

13 013 044 073 104 134 165 195 226 257 287 318 348 13 

14 014 045 074 105 135 166 196 227 258 288 319 349 14 

15 015 046 075 106 136 167 197 228 259 289 320 350 15 

16 016 047 076 107 137 168 198 229 260 290 321 351 16 

17 017 048 077 108 138 169 199 230 261 291 322 352 17 

18 018 049 078 109 139 170 200 231 262 292 323 353 18 

19 019 050 079 110 140 171 201 232 263 293 324 354 19 

20 020 051 080 111 141 172 202 233 264 294 325 355 20 

21 021 052 081 112 142 173 203 234 265 295 326 356 21 

22 022 053 082 113 143 174 204 235 266 296 327 357 22 

23 023 054 083 114 144 175 205 236 267 297 328 358 23 

24 024 055 084 115 145 176 206 237 268 298 329 359 24 

25 025 056 085 116 146 177 207 238 269 299 330 360 25 

26 026 057 086 117 147 178 208 239 270 300 331 361 26 

27 027 058 087 118 148 179 209 240 271 301 332 362 27 

28 028 059 088 119 149 180 210 241 272 302 333 363 28 

29 029 060 089 120 150 181 211 242 273 303 334 364 29 

30 030 090 121 151 182 212 243 274 304 335 365 30 

31 031 091 152 213 244 305 366 31 

Day JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC DAY
NOAA/EPA Brewer Network Site Health and Status Check List 

Site Name: Date/Time:

Brewer Serial #: Operator:

Daily System Checks 

Completed Task Description Results or Comments 

Verify Brewer CUT (Coordinated Universal Time) 

is within several seconds of the NIST Time 

Standard. Refer to Section 2.2.1 of the Site 

Operators Hand Book. 

Verify Brewer Schedule is running. Record the 

Schedule Name and Brewer Software Version. 

 Schedule Name: ____________ 

Brewer SW Version: ____________ 

Clean UV Dome and Quartz Window with paper 

towel and window cleaner. 

Verify and record the Humidity Indicator Value. If 

Humidity is greater than 20% refer to Desiccant 

Replacement in Section 4.4 of the Site Operators 

Handbook. 

Humidity Value: ____________ 

____ Desiccant Bags Replaced 

____ Breather Tube Desiccant Cartridge Replaced 

Verify Brewer is tracking the Sun. 

Verify the cables are not stressed or wrapped 

tightly around the Tracker/Tripod. 

Brewer Sun Sighting (Weekly) 

Completed Task Description Results 

Perform the Sun Sighting Procedure defined in 

Section 4.5 of the Site Operators Handbook. Horizon Correction North Correction 

Old Value New Value Old Value New Value 

Tracker Inspection and Maintenance (Bi-Monthly) 

Completed Task Description Results or Comments 

Perform the Track Steps Per Revolution Test 

defined in Section 5 of the Site Operators 

Handbook. 

Previous SR Value: 

Latest SR Value: 

Inspect and Clean the Tracker Friction Wheel as 

shown in Section 5 of the Site Operators 

Handbook. 

Condition of Wheel and shaft: 

Inspect the Condition of the Rotation Protection 

Switch inside the Tracker Case. Verify Cable is 

attached securely. 

Condition of Switch and Cable:

Other Comments or Notes: 

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________

____________________________________________________________________________