Microchip Technology CSIII User manual

 2021 Microchip Technology Inc. Advance Information DS50003057A
CSIII (Model 4310B) User’s
Guide

DS50003057A-page 2 Advance Information  2021 Microchip Technology Inc.
Information contained in this publication is provided for the sole
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Trademarks
The Microchip name and logo, the Microchip logo, Adaptec,
AnyRate, AVR, AVR logo, AVR Freaks, BesTime, BitCloud, chipKIT,
chipKIT logo, CryptoMemory, CryptoRF, dsPIC, FlashFlex,
flexPWR, HELDO, IGLOO, JukeBlox, KeeLoq, Kleer, LANCheck,
LinkMD, maXStylus, maXTouch, MediaLB, megaAVR, Microsemi,
Microsemi logo, MOST, MOST logo, MPLAB, OptoLyzer,
PackeTime, PIC, picoPower, PICSTART, PIC32 logo, PolarFire,
Prochip Designer, QTouch, SAM-BA, SenGenuity, SpyNIC, SST,
SST Logo, SuperFlash, Symmetricom, SyncServer, Tachyon,
TimeSource, tinyAVR, UNI/O, Vectron, and XMEGA are registered
trademarks of Microchip Technology Incorporated in the U.S.A. and
other countries.
AgileSwitch, APT, ClockWorks, The Embedded Control Solutions
Company, EtherSynch, FlashTec, Hyper Speed Control, HyperLight
Load, IntelliMOS, Libero, motorBench, mTouch, Powermite 3,
Precision Edge, ProASIC, ProASIC Plus, ProASIC Plus logo, Quiet-
Wire, SmartFusion, SyncWorld, Temux, TimeCesium, TimeHub,
TimePictra, TimeProvider, WinPath, and ZL are registered
trademarks of Microchip Technology Incorporated in the U.S.A.
Adjacent Key Suppression, AKS, Analog-for-the-Digital Age, Any
Capacitor, AnyIn, AnyOut, Augmented Switching, BlueSky,
BodyCom, CodeGuard, CryptoAuthentication, CryptoAutomotive,
CryptoCompanion, CryptoController, dsPICDEM, dsPICDEM.net,
Dynamic Average Matching, DAM, ECAN, Espresso T1S,
EtherGREEN, IdealBridge, In-Circuit Serial Programming, ICSP,
INICnet, Intelligent Paralleling, Inter-Chip Connectivity,
JitterBlocker, maxCrypto, maxView, memBrain, Mindi, MiWi,
MPASM, MPF, MPLAB Certified logo, MPLIB, MPLINK, MultiTRAK,
NetDetach, Omniscient Code Generation, PICDEM, PICDEM.net,
PICkit, PICtail, PowerSmart, PureSilicon, QMatrix, REAL ICE,
Ripple Blocker, RTAX, RTG4, SAM-ICE, Serial Quad I/O,
simpleMAP, SimpliPHY, SmartBuffer, SMART-I.S., storClad, SQI,
SuperSwitcher, SuperSwitcher II, Switchtec, SynchroPHY, Total
Endurance, TSHARC, USBCheck, VariSense, VectorBlox, VeriPHY,
ViewSpan, WiperLock, XpressConnect, and ZENA are trademarks
of Microchip Technology Incorporated in the U.S.A. and other
countries.
SQTP is a service mark of Microchip Technology Incorporated in
the U.S.A.
The Adaptec logo, Frequency on Demand, Silicon Storage
Technology, and Symmcom are registered trademarks of Microchip
Technology Inc. in other countries.
GestIC is a registered trademark of Microchip Technology Germany
II GmbH & Co. KG, a subsidiary of Microchip Technology Inc., in
other countries.
All other trademarks mentioned herein are property of their
respective companies.
© 2021, Microchip Technology Incorporated, All Rights Reserved.
ISBN: 978-1-5224-7867-6
For information regarding Microchip’s Quality Management Systems,
please visit www.microchip.com/quality.

CSIII (MODEL 4310B) USER’S GUIDE
 2021 Microchip Technology Inc. DS50003057A-page 3
Preface
PURPOSE OF THIS GUIDE
The CSIII user guide provides basic recommendations for use of Microchip's CSIII
4310B cesium reference.
WHO SHOULD READ THIS GUIDE
This document is intended for engineers and technicians who have purchased the
CSIII and need to understand how to operate the product.
DOCUMENT LAYOUT
This guide contains the following sections:
•Chapter 1. “Product Overview”: Provides an overview of the product, describes
the major hardware and software features, and lists the system specifications.
•Chapter 2. “Installation”: Contains the Principle of Operation, Start-Up
Sequence, and aspects related to first power-up.
•Chapter 3. “Operation”: Provides an overview of the telemetry interface and
command structure.
•Chapter 4. “Maintenance and Troubleshooting”: Contains information on
required maintenance, troubleshooting, shipping and cesium tube replacement.
•Chapter 5. “Theory of Operation”: Explains principals of operation.
•Appendix A. “Specifications”: Refers to latest product specifications in product
data sheet DS00003499.
•Appendix B. “Programmer’s Guide”: This section describes the protocol for the
RS-232 interface and includes general communication parameters and the com-
mand list. Note that this section is designed for experienced programmers and
assumes a general knowledge of RS-232 interface programming.
•Appendix C. “Customer Assistance/Technical Support”: This appendix con-
tains information about contacting Microchip using support services.
NOTICE TO CUSTOMERS
All documentation becomes dated, and this manual is no exception. Microchip tools and
documentation are constantly evolving to meet customer needs, so some actual dialogs
and/or tool descriptions may differ from those in this document. Please refer to our website
(www.microchip.com) to obtain the latest documentation available.
Documents are identified with a “DS” number. This number is located on the bottom of each
page, in front of the page number. The numbering convention for the DS number is
“DSXXXXXXXXA”, where “XXXXXXXX” is the document number and “A” is the revision level
of the document.
For the most up-to-date information on development tools, see the MPLAB® IDE online help.
Select the Help menu, and then Topics, to open a list of available online help files.

CSIII (Model 4310B) User’s Guide
DS50003057A-page 4  2021 Microchip Technology Inc.
CONVENTIONS USED IN THIS GUIDE
This manual uses the following documentation conventions:
DOCUMENTATION CONVENTIONS
Description Represents Examples
Arial font:
Italic characters Referenced books MPLAB® IDE User’s Guide
Emphasized text ...is the only compiler...
Initial caps A window the Output window
A dialog the Settings dialog
A menu selection select Enable Programmer
Quotes A field name in a window or
dialog
“Save project before build”
Underlined, italic text with
right angle bracket
A menu path File>Save
Bold characters A dialog button Click OK
A tab Click the Power tab
N‘Rnnnn A number in verilog format,
where N is the total number of
digits, R is the radix and n is a
digit.
4‘b0010, 2‘hF1
Text in angle brackets < > A key on the keyboard Press <Enter>, <F1>
Courier New font:
Plain Courier New Sample source code #define START
Filenames autoexec.bat
File paths c:\mcc18\h
Keywords _asm, _endasm, static
Command-line options -Opa+, -Opa-
Bit values 0, 1
Constants 0xFF, ‘A’
Italic Courier New A variable argument file.o, where file can be
any valid filename
Square brackets [ ] Optional arguments mcc18 [options] file
[options]
Curly brackets and pipe
character: { | }
Choice of mutually exclusive
arguments; an OR selection
errorlevel {0|1}
Ellipses... Replaces repeated text var_name [,
var_name...]
Represents code supplied by
user
void main (void)
{ ...
}

Preface
 2021 Microchip Technology Inc. DS50003057A-page 5
WARNINGS, CAUTIONS, RECOMMENDATIONS, AND NOTES
Warnings, Cautions, Recommendations, and Notes attract attention to essential or crit-
ical information in this guide. The types of information included in each are displayed
in a style consistent with the examples below.
WHERE TO FIND ANSWERS TO PRODUCT AND DOCUMENT QUESTIONS
For additional information about the products described in this guide, please contact
your Microchip representative or your local sales office. You can also contact us on the
web at www.microsemi.com/ftdsupport.
When this manual is updated the latest version will be available for downloading from
Microchip’s web site. Manuals are provided in PDF format for ease of use. After down-
loading, you can view the manual on a computer or print it using Adobe Acrobat
Reader.
Manual updates are available at: www.microsemi.com/ftdsupport
RELATED DOCUMENTS AND INFORMATION
See your Microchip representative or sales office for a complete list of available docu-
mentation. To order any accessory, contact the Microchip Sales Department. See
www.microsemi.com/sales-contacts/0 for sales support contact information. If you
encounter any difficulties installing or using the product, contact Microchip Frequency
and Time Systems (FTS) Services and Support:
U.S.A. Call Center: including Americas, Asia and Pacific Rim
Frequency and Time Systems
3870 N 1st St.
San Jose, CA 95134
Toll-free in North America: 1-888-367-7966
Telephone: [phone]
Fax: [phone]
WARNING
To avoid serious personal injury or death, do not disregard warnings. All warnings use
this style. Warnings are installation, operation, or maintenance procedures, practices,
or statements, that if not strictly observed, may result in serious personal injury or even
death.
CAUTION
To avoid personal injury, do not disregard cautions. All cautions use this style. Cau-
tions are installation, operation, or maintenance procedures, practices, conditions, or
statements, that if not strictly observed, may result in damage to, or destruction of, the
equipment. Cautions are also used to indicate a long-term health hazard.
Note: All notes use this style. Notes contain installation, operation, or mainte-
nance procedures, practices, conditions, or statements that alert you to
important information, which may make your task easier or increase your
understanding.

CSIII (Model 4310B) User’s Guide
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email: [email protected]
Internet: www.microsemi.com/ftdsupport
Europe, Middle East, and Africa (EMEA)
Microchip FTS Services and Support EMEA
Altlaufstrasse 42
85635 Hoehenkirchen-Siegertsbrunn
Germany
Telephone: [phone]
Fax: [phone]
email: [email protected]
email: [email protected]
THE MICROCHIP WEBSITE
Microchip provides online support via our website at www.microchip.com. This website
is used as a means to make files and information easily available to customers.
Accessible by using your favorite Internet browser, the website contains the following
information:
•Product Support – Data sheets and errata, application notes and sample
programs, design resources, user’s guides and hardware support documents,
latest software releases and archived software
•General Technical Support – Frequently Asked Questions (FAQs), technical
support requests, online discussion groups, Microchip consultant program
member listing
•Business of Microchip – Product selector and ordering guides, latest Microchip
press releases, listing of seminars and events, listings of Microchip sales offices,
distributors and factory representatives
CUSTOMER SUPPORT
Users of Microchip products can receive assistance through several channels:
• Distributor or Representative
• Local Sales Office
• Field Application Engineer (FAE)
• Technical Support
Customers should contact their distributor, representative or field application engineer
(FAE) for support. Local sales offices are also available to help customers. A listing of
sales offices and locations is included in the back of this document.
Technical support is available through the website at:
http://www.microchip.com/support.
DOCUMENT REVISION HISTORY
Revision A (December 2020)
• Initial release of this document as Microchip DS50003057A.
- Under Microsemi’s literature system, this document was 900-00509-000,
rev B.

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Table of Contents
Preface ............................................................................................................................ 3
Purpose of This Guide........................................................................................... 3
Who Should Read This Guide............................................................................... 3
Document Layout .................................................................................................. 3
Conventions Used in this Guide ............................................................................ 4
Warnings, Cautions, Recommendations, and Notes............................................. 5
Where to Find Answers to Product and Document Questions .............................. 5
Related Documents and Information..................................................................... 5
The Microchip Website.......................................................................................... 6
Customer Support ................................................................................................. 6
Document Revision History ................................................................................... 6
Chapter 1. Product Overview ........................................................................................ 9
1.1 Introduction...................................................................................................... 9
1.2 LED Indicators................................................................................................. 9
1.3 Rear Panel Connections ................................................................................. 9
1.4 Software ........................................................................................................ 10
1.5 Power ............................................................................................................ 10
1.6 Factory Configurations .................................................................................. 10
Chapter 2. Installation.................................................................................................. 11
2.1 Installation ..................................................................................................... 11
2.2 Unpacking Instructions .................................................................................. 11
2.3 Environmental Considerations ...................................................................... 11
2.4 Pre-Installation Checklist............................................................................... 11
2.5 Tools and Materials ....................................................................................... 12
2.6 Installing the CsIII.......................................................................................... 12
2.7 Installing the Monitor3 Software .................................................................... 13
2.8 Establishing Communications ....................................................................... 13

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Chapter 3. Operation ....................................................................................................15
3.1 Monitor3 main Status Window....................................................................... 15
3.2 Unit Monitoring and Data Logging................................................................. 16
3.3 Adjusting Output Frequencies....................................................................... 18
3.4 Synchronizing to a 1PPS Source .................................................................. 18
3.5 Slewing the Output Phase............................................................................. 19
3.6 Alarms ........................................................................................................... 20
3.7 Event Logging ............................................................................................... 21
3.8 Factory Settings ............................................................................................ 21
3.9 Communications............................................................................................ 22
Chapter 4. Maintenance and Troubleshooting ..........................................................23
4.1 Preventive Maintenance................................................................................ 23
4.2 Troubleshooting............................................................................................. 24
4.3 Shipping ........................................................................................................ 24
4.4 Hazardous material (HAZMAT) Shipping Considerations............................. 24
4.5 Shipping Products Back to the Factory ......................................................... 24
4.6 Shipping Carriers........................................................................................... 25
4.7 Storage.......................................................................................................... 25
4.8 Cesium Beam Tube Vacuum ........................................................................ 25
4.9 Cesium Beam Tube Shelf Life....................................................................... 25
Chapter 5. Theory of Operation...................................................................................27
5.1 Cesium beam Frequency Standard Concept ................................................ 27
5.2 Cesium Beam Tube....................................................................................... 28
5.3 Clock Servo................................................................................................... 32
5.4 Zeeman Servo............................................................................................... 33
5.5 Gain Servo .................................................................................................... 33
5.6 Microwave Power Servo................................................................................ 34
5.7 Unit Initialization ............................................................................................ 35
5.8 Alarms and Indicators.................................................................................... 36
Appendix A. Specifications .........................................................................................37
A.1 Alarm Interface.............................................................................................. 37
A.2 Options.......................................................................................................... 37
Appendix B. Programmer’s Guide ..............................................................................39
B.1 General Parameters...................................................................................... 39
B.2 Restart Message........................................................................................... 39
B.3 Cesium Command Reference....................................................................... 40
B.4 Event Log...................................................................................................... 45
Appendix C. Customer Assistance/Technical Support ............................................47
Worldwide Sales and Service .....................................................................................49

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Chapter 1. Product Overview
1.1 INTRODUCTION
The Microchip CsIII Cesium Beam Frequency Standard is designed for high-precision
timing and frequency applications requiring high stability, low-noise RF, and 1PPS ref-
erence signals. The CsIII comes in a standard 19-inch wide rack mount housing. It is
2U high (3.75”) and weighs 28 lbs (12.7 kg). For more information, see Appendix
A. “Specifications”.
1.2 LED INDICATORS
The following indicators are available on both the front and the rear panel.
• Power Indicator - Indicates power applied to instrument (green LED)
• Lock Indicator - Indicates normal operation (green LED)
• Alarm Indicator - Indicates unit alarm condition (red LED)
FIGURE 1-1: CsIII Front Panel.
1.3 REAR PANEL CONNECTIONS
• 5 MHz - BNC 5 MHz output (50Ω)
• 10 MHz - BNC 10 MHz output (50Ω)
• 10 MHz TTL - BNC 10 MHz TTL output (50Ω)
• 1PPS - BNC 1PPS output (50 Ω)
• SYNC - BNC input to synchronize 1PPS output to external source (50Ω)
• ALARM - DB9 Female, Form C relay
• RS-232 - DB9 Male DTE
FIGURE 1-2: CsIII Rear Panel.

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1.4 SOFTWARE
The CsIII’s principal user interface is the Microchip Monitor3 software. Monitor3 runs
on Microsoft Windows PCs (Windows 95 or newer) and connects to the CsIII with a
standard RS-232 null modem cable. In addition to providing comprehensive configura-
tion and control of the CsIII, Monitor3 provides periodic monitoring of the instrument’s
state-of-health parameters and optionally logs data to disk for subsequent analysis.
Monitor3 also provides logging of Alarm events to a log file for monitoring and trouble-
shooting purposes. Monitor3 is not essential to operate the CsIII if there is no need to
modify factory default parameters, adjust frequency or phase of outputs, or to monitor
internal health parameters. In some applications, users may develop their own inter-
face software for control and monitoring of the CsIII. For more information about the
RS-232 command structure and command list, see Appendix B. “Programmer’s
Guide”.
1.5 POWER
External power is supplied by a standard AC power cord or by a DC power connection.
The following is the power hierarchy.
• The unit operates from the AC power, if AC power is available.
• The unit operates from the DC input, If DC power is available and AC power is
not.
FIGURE 1-3: DC Input and Pin Assignments.
1.6 FACTORY CONFIGURATIONS
The CsIII is available with optional features that permit the system designer to specify
the most cost- effective solution for a particular application. Optional features include:
• E1 or T1 telecommunication outputs
For complete list of options, see Appendix A. “Specifications”.
Mating Connector:
ACS02E14S-5P-472

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Chapter 2. Installation
2.1 INSTALLATION
This section provides unpacking instructions and installation procedures for the CsIII
as well as warnings, cautions, notes, and recommendations that pertain to the proce-
dures. If you encounter problems during any of the following procedures, contact Tech-
nical Support (see Appendix C. “Customer Assistance/Technical Support”).
2.2 UNPACKING INSTRUCTIONS
1. Inspect the container for signs of damage. If the container appears to be dam-
aged, notify both the carrier and the Microchip distributor. Retain the shipping
container and packing material for the carrier to inspect.
2. Unpack all components in the shipping container.
3. Inventory, and set aside all items and paperwork that are included in the con-
tainer.
4. Verify that the model and item number shown on the shipping list matches the
information on the equipment. The item number can be found on a label affixed
to the rear panel. Contact the Microchip distributor if the model or item numbers
do not match.
2.3 ENVIRONMENTAL CONSIDERATIONS
When installing the instrument, consider the standard environmental factors (tempera-
ture, humidity, vibration, and so on) and the presence of magnetic fields that might
affect the accuracy of the CsIII. Avoid installing or using the instrument near large
motors, generators, transformers, and other equipment that radiates strong AC or DC
fields of 2 gauss or more.
2.4 PRE-INSTALLATION CHECKLIST
Before installation, ensure that the following preparations are in place:
• The equipment rack is grounded and has power available
• Sufficient space is available in the equipment rack to accommodate the 2U CsIII
as well as an additional 1U of space above and below the CsIII
• Chassis rack supports or slides are available to support the CsIII
CAUTION
To avoid damage to the system, access covers must not be removed, except by trained
service personnel.
CAUTION
To avoid electrostatic discharge (ESD) damage to sensitive internal parts, observe
proper ESD handling procedures.

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2.5 TOOLS AND MATERIALS
The following is a list of recommended tools and materials (not supplied):
• Standard tool kit
• Rack supports or slide mounts
• Personal computer running Windows 95 or newer with one available serial port
• Null modem cable
2.6 INSTALLING THE CSIII
The CsIII mounts in a standard 19-inch equipment rack. The CsIII side plates are drilled
and tapped to accept chassis rack slides. The use of chassis rack slides or other means
of support is necessary because of the weight and weight distribution of the instrument.
The front panel occupies a height of 3.75” (2U).
• Mount the CsIII in the desired location in the equipment rack using standard rack
mount hardware. Install the proper fuse into the fuse holder marked DC fuse on
the rear panel. Fuse specifications are provided on the instrument’s rear panel.
• If available, apply AC power to the CsIII by installing the detachable power supply
cord at the AC Input connection on the rear panel.
• Apply DC power to DC input, if available.
• Observe that the power and alarm front panel indicators are illuminated. Wait for
the unit to complete its initial acquisition sequence and stabilize. This may take up
CAUTION
To avoid damage to the system, access covers must not be removed, except by trained
service personnel.
WARNING
For continued protection against risk of fire, ensure that only the specified fuse type
and rating are used. Fuse specifications are provided on the instrument’s rear panel.
CAUTION
To prevent damage to the instrument during installation, disconnect the power by
removing the fuse from the rear panel. The fuse is the emergency disconnect for the
device—there is no ON/OFF switch.
CAUTION
The instrument is convection cooled. To prevent the instrument from overheating,
leave one rack unit (1.75 in./4.44 cm) space above the unit for cooling.
CAUTION
To avoid electrostatic discharge (ESD) damage to components inside the instrument,
observe proper ESD handling procedures.

Installation
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to 30 minutes. When stabilized, the alarm indicator turns off and the lock indicator
illuminates. The alarm relay is reset and all signal outputs are activated.
Note: Applying the power to the instrument initiates the warm-up and automatic
lock acquisition sequence. During this time, the alarm relay is activated and
the signal outputs are not active.
2.7 INSTALLING THE MONITOR3 SOFTWARE
The Monitor3 software runs on any PC or laptop running Microsoft Windows 95 or
newer. It requires less than 1 MB of disk space and one available serial (COM) port to
connect to the CsIII.
Following are the steps to install the Monitor3 software:
1. Download the Monitor3 software from Microchip FTD support website.
2. Install the application by running the setup.exe file.
By default, the Monitor3 application is installed in the c:\Program Files\Symmetricom
directory. A folder named “Symmetricom” is added to your Start menu containing an
icon for the Monitor3 application. An uninstall icon is also added so that you can easily
remove the program in the future.
For DB9 connector, see the following table for connector pin-out information.
2.8 ESTABLISHING COMMUNICATIONS
Connect the serial port of the computer to the RS-232 port of the CsIII using a standard
RS-232 null modem cable. Click Start, select Programs > Symmetricom > Monitor3.
The Monitor3 interface appears as shown in Figure 3-1.
The following are the default RS-232 settings of CsIII.
• BAUD = 9600
• Data bits = 7
• Parity = Odd
• Stop bits = 2
To reconfigure these settings on the CsIII, see Appendix B. “Programmer’s Guide”.
By default, Monitor3 initially attempts to connect to the instrument using the above
parameters and PC serial port COM1. To check or adjust these communication param-
eters, select Configure Serial Port from the File menu. The panel shown in Figure 2-1
appears. Use this panel to adjust the Monitor3 serial communications parameters to
agree with the setting of the CsIII instrument.
TABLE 2-1: RS-233 PORT DB9 TO DB25 CONNECTOR PIN-OUT
DB9-M DB25-F Function
3 3 Rx Data
2 2 Tx Data
5 7 Signal GND
TABLE 2-2: RS-232 PORT DB9 TO DB9 CONNECTOR PIN-OUT
DB9-M DB9-F Function
3 2 Rx Data
2 3 Tx Data
5 5 Signal GND

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FIGURE 2-1: Serial Communication Setup.
The modified settings are applied when the Apply Changes button is depressed, at that
time Monitor3 resets the serial port and attempts to re-establish communication with
the Cesium instrument. After communication has been successfully established, the
communication parameters of the CsIII can be modified, see Appendix
B. “Programmer’s Guide”.
In the event of communication problems, the Detect button may be employed to
sequentially test the interface at a variety of communication parameters and locate the
instrument.
By default, Monitor3 interrogates the CsIII and updates the screen information every
ten seconds. The status bar, in the lower left of the main window, that reports count-
down to the next update and communication activity as it occurs, indicates RS-232 sta-
tus. In the event of communication failure, the status bar indicates “Unit Not
Responding”. In that case, Monitor3 periodically reinitializes the communication port
and attempt to establish communication.
When communication has been successfully established, the Monitor3 interface
appears as shown in Figure 3-1. The title bar of the Monitor3 application window
reflects the instrument type (here, CsIII), the serial number (here 6172), and the PC
RS-232 interface (here, COM2). Instrument state is indicated in the lower right status
bar (here, Operating). By default, the displayed data updates every 10 seconds. The
RS-232 status bar, on the lower left, indicates countdown to the next update and
RS-232 activity as it occurs.

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Chapter 3. Operation
Prior to performing any of the operations described in this section, ensure that the
installation procedures described in Chapter 2. “Installation” have been performed
and that communication has been established between the CsIII and the Monitor3
application software.
In some installations, users may develop custom application software to provide
remote control and monitoring capability. For more information about command syntax
and complete command reference, see Appendix B. “Programmer’s Guide”.
3.1 MONITOR3 MAIN STATUS WINDOW
The Figure 3-1 shows the Monitor3 main status window under normal operating condi-
tions. The title bar of the main window indicates the Cesium instrument model, serial
number, and PC communication port. The status bar at the bottom of the main window
indicates RS-232 communication activity on the left and instrument status (Warming
Up, Operating, Minor Fault, or Major Fault) on the right.
FIGURE 3-1: Monitor3 Main Status Window.
The body of the main window displays operating and configuration data for the CsIII
instrument. The main window updates periodically (see Section 3.2 “Unit Monitoring
and Data Logging”). The left-hand column reflects parameters associated with the
digital operating servos, including the main Clock Servo, the C-Field or Zeeman servo,
the Gain Servo, and the Microwave Power Servo. The middle column contains the Sys-
tem Information, user programmed Frequency Offset, and Cesium Beam Tube Power
Supplies monitors. The right hand column displays monitors of the internal Power Sup-
plies. The definitions, interpretation, and normal values of the displayed data are dis-
cussed in the following sections and Appendix B. “Programmer’s Guide”.

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3.2 UNIT MONITORING AND DATA LOGGING
To adjust the polling rate and/or enable logging of data to disk, select Configure Unit
Monitoring from the File menu.
FIGURE 3-2: Unit Monitoring Options.
From the Unit Monitoring panel, shown above, enable or disable monitoring with the
Enable Monitoring check box and adjust the polling rate by typing a value into the
Polling Rate edit box.
To save the monitor data to the PC’s hard disk for archive or subsequent analysis,
enable the Save to Disk check box. The data is saved at each polling interval in the
directory specified. The output directory can be changed either by typing a new direc-
tory name into the directory field or by activating the Browse... panel and selecting a
new directory from the tree displayed therein. Note that the data is not saved if the
specified directory does not exist.
The name for the data file may be entered into the Data Filename Template field. The
macro field %ld is replaced with the serial number of the CsIII instrument when the file
is created. In this example, the saved data would appear in the file: c:\Unit6172_-
Data.csv.
The saved data file contains 38 comma-delimited columns. The first row of the file con-
tains the column headings, which correspond with the data displayed by Monitor3 as
identified in Table 3-1. Note that the values displayed in the “Typical” column corre-
spond to those in Figure 3-1.
TABLE 3-1: INTERPRETATION OF COLUMNS IN THE DATA FILE CREATED
BY UNIT MONITORING
Column Heading Description Typical Range Units
1 MJD
Fractional days since 0hr
November 17, 1858.
Measured by PC clock
52991.8122
days — Days
2 ID Serial number of unit 6172 0-99999 —
3 Unit Type Model identifier 400 400 - 410 —
4 Factory Data taken at factory 0 0, 1 —
5 State Instrument State 00
00: Operating
01: Warm-up
10: Minor Alarm
11: Major Alarm
—

Operation
 2021 Microchip Technology Inc. DS50003057A-page 17
6 Alarm 1 First element of prevailing
alarm list 00 00 - FF —
7 Alarm 2 Second element of prevailing
alarm list 00 00 - FF —
8 Alarm 3 Third element of prevailing
alarm list
00 00 - FF —
9 Alarm 4 Fourth element of prevailing
alarm list
00 00 - FF —
10 Alarm 5 Fifth element of prevailing
alarm list
00 00 - FF —
11 StdDev Signal Standard Deviation 0 100-200 (SP)
50-100 (EP)
mV
12 CRamErr Clock Transition Ramsey
Error
0 ±9999 mV
13 CRabErr Clock Transition Rabi Error 2 ±9999 mV
14 CLevel Clock Transition Signal Level 2181 0-9999 mV
15 VVCXO VCXO Control Voltage 3666 0-5000 mV
16 ZRamErr Zeeman Transition Ramsey
Error
0 ±9999 mV
17 ZRabErr Zeeman Transition Rabi Error 8 ±9999 mV
18 ZLevel Zeeman Transition Signal
Level
2262 0-9999 mV
19 VCField C-Field Control Voltage 23 ±2500 mV
20 ICField C-Field Current 19 17-21 mV
21 VuWave Microwave Power Control 1809 0-5000 mV
22 DCLevel DC Signal Level 2971 0-5000 mV
23 DACGain Digital Preamplifier Gain 2.61 0-255 mV
24 NumGain Numerical Gain 1.17 0.1-9999 —
25 TChasis Chassis Temperature 38.3 0-99 °C
26 VcsOven Cesium Oven Heater Voltage 6.5 0-15 V
27 OscState OCXO Oven State Ready “Cold” or
“Ready”
—
28 VEM Electron Multiplier Control
Voltage
8.7 5-10 V
29 IIP Ion Pump Current 0 0-10 µA
30 VMS Mass Spectrometer Bias Volt-
age
16.6 12-18 V
31 VION Ionizer Voltage Drop 1.0 0.5-1.5 V
32 OCXOTau Clock OCXO Loop Time Con-
stant
1.0 0.1-99.9 sec.
33 FreqTune User Frequency Offset — ±999999 x10–15
34 Pos24V 21 VDC Secondary Supply 21.71 0-99.99 V
35 Pos5V 5 VDC Secondary Supply 5.06 0-99.99 V
35 Pos15V +15 VDC Secondary Supply 15.6 0-99.99 V
37 Neg15V –15 VDC Secondary Supply –15.5 –99.99-0 V
38 Version Cesium Module Firmware
Version
D 1762 — —
TABLE 3-1: INTERPRETATION OF COLUMNS IN THE DATA FILE CREATED
BY UNIT MONITORING (CONTINUED)
Column Heading Description Typical Range Units

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3.3 ADJUSTING OUTPUT FREQUENCIES
The output frequency of the CsIII may be adjusted by ȳ = ±1 x 10–9 with a resolution of
1 part in 1015. This is generally used for calibration purposes and is accomplished by
directly modifying the fundamental interrogation frequencies of the physics package,
and is thereby reflected on all outputs. To modify the programmed offset frequency,
select Delta-F from the Outputs menu.
Note: Unless noted otherwise, all references to frequency refer to fractional fre-
quency (Hz/Hz) and not absolute frequency (Hz).
FIGURE 3-3: Adjust Output Frequency.
The Adjust Output Frequency panel appears, as shown Figure 3-3, reflecting the cur-
rent programmed offset of the CsIII, in this case ȳ = 1 x 10–13. To change the offset fre-
quency, enter a new value, between –999999 and 999999, into the edit field and click
Apply Changes to upload the correction to the CsIII. To exit the Adjust Output Fre-
quency panel without applying changes, select Cancel. The updated output adjustment
is reflected in the Frequency Offset field following the next RS-232 update of the dis-
played data.
3.4 SYNCHRONIZING TO A 1 PPS SOURCE
The 1 PPS output of the CsIII is generated by direct division of the 10 MHz RF output
and, as such, reflects the phase of one particular cycle of the 10 MHz. To synchronize
the 1 PPS output to an external user-supplied 1 PPS source, with 100 nS resolution,
connect the 1PPS source to the back-panel 1 PPS Sync input and select Synchronize
1 PPS to External Source from the Outputs menu. The panel appears as shown in
Figure 3-4.

Operation
 2021 Microchip Technology Inc. DS50003057A-page 19
FIGURE 3-4: Synchronize 1 PPS to External Source.
The CsIII synchronizes its 1PPS outputs to within ±100 ns of the applied external 1PPS
source if a rising edge is detected within three seconds after pressing the Sync button.
Select Cancel to exit the panel without re-synchronizing the 1 PPS output.
3.5 SLEWING THE OUTPUT PHASE
To provide finer resolution adjustment of the output phase that is available from the
1 PPS Synchronization feature, the output phase can be slewed, with 1 ns resolution,
using the Delta-T function. This function is implemented by deliberately offsetting the
output frequency of the CsIII by either ȳ = 1 x 10–9 or ȳ = –1 x 10–9 or N seconds,
thereby introducing a phase offset of plus or minus N ns, respectively. Note that, unlike
the 1PPS synchronization feature, the Delta-T function affects the phase on all outputs,
including RF and 1PPS.
Note that the output frequency of the instrument is significantly perturbed, by ȳ = ± 1 x
10–9, for the duration of the adjustment. For example, phase advance of 1 ms, intro-
duces a ȳ = 1 x 10–9 error in all clock outputs, persisting for 1,000,000 seconds, almost
12 days. To avoid introducing an offset for such a long duration, it is recommended to
use the Sync 1PPS feature to bring the phase to within 100 ns of the desired value.
FIGURE 3-5: Slew Output Phase.
In order to adjust the output phase, select Delta-T… from the Outputs menu. The Slew
Output Phase panel appears. Enter the desired output phase, in the range of 0- ns and
select either Advance or Retard from the pull down menu. Press Begin Slew to begin
the phase slewing operation. The output frequency of the CsIII is immediately offset by
either ȳ = 1 x 10–9 or ȳ = –1 x 10–9, depending on whether Advance or Retard is
selected, respectively. To abort the phase slewing operation in process, and return the
instrument to its nominal frequency, return to the Slew Output Phase panel and press
the Abort button at any time during the operation.

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3.6 ALARMS
The CsIII microprocessor system provides continuous monitoring of system power sup-
plies, signal quality, and numerous physics package operating parameters, as indi-
cated on the Monitor3 main panel. Alarms are generated in the event that any of the
parameters deviate from its acceptable value.
Alarms are classified into two types:
• Minor Alarm—Indicates out of nominal specification that should be noted but is
not expected to impact instrument performance.
• Major Alarm—Indicates detection of a fault that causes the instrument to fail to
meet specification.
In the event of Minor Alarm, the ALARM LED illuminates on the instrument front panel,
in addition to the POWER and LOCK LEDs. All outputs remain active and the ALARM
LED remains illuminated for as long as the alarm condition persists.
In the event of Major Alarm, the LOCK LED turns off and the ALARM LED illuminates.
All outputs are disabled. If the alarm condition ceases, the instrument restarts from its
initial power-on condition. The current list of alarms is indicated, by hexadecimal code
in the alarm list on the Monitor3 main panel. To see an annotated list of alarms, clear
alarms, or set the priority of the restart alarm, select Alarms... from the View menu.
FIGURE 3-6: Alarms.
The Alarms panel, shown above, enumerates all alarms currently present in the sys-
tem. To clear standing alarms, press the Reset Alarms button. The list of pending
alarms is updated at the next regular polling interval. For a complete list of possible
alarms, see Chapter 4. “Maintenance and Troubleshooting”.
There are two possible alarm strategies in the event of unit restart, which may be
selected from the Restart Alarm Strategy pull-down menu and uploaded to the CsIII by
pressing the Apply Changes button. These are:
• Non-Critical (Default) - In the event of restart, the 0x16 alarm flag is set, outputs
are muted during re-acquisition and restored upon successful lock. The 0x16
alarm flag remains set until cleared by the user.
• Critical - In the event of restart, the 0x16 flag is set, outputs are muted during
reacquisition and remain muted thereafter until the user clears the 0x16 alarm
flag.