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- Page 1 CSIII (Model 4310B) User’s Guide Advance Information 2021 Microchip Technology Inc. DS50003057A...
- Page 2 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.
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Page 3: Preface
Select the Help menu, and then Topics, to open a list of available online help files. 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. -
Page 4: Conventions Used In This Guide
CSIII (Model 4310B) User’s Guide 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... -
Page 5: Warnings, Cautions, Recommendations, And Notes
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: 408-428-7907 Fax: 408-428-7998 2021 Microchip Technology Inc. DS50003057A-page 5... -
Page 6: The Microchip Website
CSIII (Model 4310B) User’s Guide email: ftd.support@microsemi.com Internet: www.microsemi.com/ftdsupport Europe, Middle East, and Africa (EMEA) Microchip FTS Services and Support EMEA Altlaufstrasse 42 85635 Hoehenkirchen-Siegertsbrunn Germany Telephone: +49 700 3288 6435 Fax: +49 8102 8961 533 email: ftd.emeasupport@microsemi.com email: ftd.emea_sales@microsemi.com THE MICROCHIP WEBSITE Microchip provides online support via our website at www.microchip.com. -
Page 7: Table Of Contents
CSIII (MODEL 4310B) USER’S GUIDE 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.............. - Page 8 CSIII (MODEL 4310B) User’s Guide 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 ......................
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Page 9: Chapter 1. Product Overview
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. -
Page 10: Software
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. -
Page 11: Chapter 2. Installation
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. -
Page 12: Tools And Materials
• Null modem cable 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. -
Page 13: Installing The Monitor3 Software
Signal GND 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. - Page 14 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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Page 15: Chapter 3. Operation
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. -
Page 16: Unit Monitoring And Data Logging
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. - Page 17 21 VDC Secondary Supply 21.71 0-99.99 Pos5V 5 VDC Secondary Supply 5.06 0-99.99 Pos15V +15 VDC Secondary Supply 15.6 0-99.99 Neg15V –15 VDC Secondary Supply –15.5 –99.99-0 Version Cesium Module Firmware D 1762 — — Version 2021 Microchip Technology Inc. DS50003057A-page 17...
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Page 18: Adjusting Output Frequencies
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... -
Page 19: Slewing The Output Phase
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. -
Page 20: Alarms
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: •... -
Page 21: Event Logging
Refresh View. Note that downloading the Event Log from the CsIII can take up to several minutes, depending on the number of events and the con- nection speed. Because of this necessary delay, the Event Log display panel is not automatically updated once initially displayed. -
Page 22: Communications
• Data bits = 7 • Parity = Odd • Stop bits = 2 In order to accommodate particular specialized installations, the RS-232 communica- tions parameters of the CsIII instrument may be adjusted from the RS-232 panel on the System menu. FIGURE 3-8: RS-232. -
Page 23: Chapter 4. Maintenance And Troubleshooting
If these are not available, contact Technical Support for a replacement. PREVENTIVE MAINTENANCE The CsIII unit requires minimum preventive maintenance. Care should be taken to insure the unit is not exposed to hazards such as direct sunlight, open windows, or extreme heat. -
Page 24: Troubleshooting
CSIII (MODEL 4310B) User’s Guide If the alarm activates and the ALARM LED remains lit indicating a failure of the CsIII, call Microchip Customer Service for instructions. Table 5-2 lists the two digit hexadecimal fault codes along with their description. Prior to calling Customer Service,... -
Page 25: Shipping Carriers
CESIUM BEAM TUBE VACUUM If the CsIII is stored for extended periods of time (>6 months), the unit should be powered on for a minimum of 30 minutes every six months in order to maintain the tube vacuum. - Page 26 CSIII (MODEL 4310B) User’s Guide NOTES: DS50003057A-page 26 2021 Microchip Technology Inc.
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Page 27: Chapter 5. Theory Of Operation
CSIII (MODEL 4310B) USER’S GUIDE Chapter 5. Theory of Operation This section provides the theory of operation of the CsIII Cesium beam frequency standard. It is intended to supplement the functional description provided in earlier chapters and provide a more complete understanding of instrument operation. -
Page 28: Cesium Beam Tube
At longer times, the output signals reflect the properties of the CBT. The following Figure 5-2 shows a block diagram of the CsIII. FIGURE 5-2: Block Diagram of the CsIII. The principal components of the CsIII include: •... - Page 29 Within the interrogation region, the atoms pass through the U-shaped resonance cavity (6, the Ramsey cavity), which induces a spin-flip resonance response with the characteristic Ramsey pattern (see the following 2021 Microchip Technology Inc. DS50003057A-page 29...
- Page 30 ADC. In the CsIII, interrogations are performed at a rate of 38 Hz and with a dwell time of 23 ms.
- Page 31 Zeeman shift. The clock transition is shown in greater detail in Figure 5-6. FIGURE 5-6: Zeeman Frequency, Clock Transition. 2021 Microchip Technology Inc. DS50003057A-page 31...
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Page 32: Clock Servo
The relative deviation of the CBT measurements is continuously monitored by the CsIII adaptive clock servo algorithm as a measure of signal quality. If the CsIII detects a transient disturbance, which might occur, for example, if the instrument is mechanically disturbed while operating, a minor alarm (0x07) is declared. -
Page 33: Zeeman Servo
. The C-field must be held stable to better than 30ppm in order to guarantee long-term stability of the CsIII at the level of 1 part in To stabilize the C-Field for long-term operation and in the presence of possibly changing external fields, the C-Field current is servoed to the atomic spectrum itself. -
Page 34: Microwave Power Servo
DAC gain is discretely adjusted if necessary. MICROWAVE POWER SERVO The short-term stability, accuracy, and environmental sensitivity of the CsIII are all optimized when the microwave power in the RF resonator is optimized to provide maximum signal level at the clock Ramsey interrogation points. -
Page 35: Unit Initialization
Maximum Signal Level at the Ramsey Interrogation Points. The optimum microwave power point, designated POPT is indicated in the above figure. To ensure that the microwave power is always optimized, the CsIII periodically measures the signal response to small variations of the microwave power, as shown in the figure, alternately performing the measurement on the left- and right-side clock Ramsey interrogation points. -
Page 36: Alarms And Indicators
CSIII (MODEL 4310B) User’s Guide ALARMS AND INDICATORS In addition to the system monitors relating to servos and Cesium beam tube parameters, periodic measurements are made of primary and secondary system voltages and CBT power supplies. These are generally self explanatory from the front panel of Monitor3. -
Page 37: Appendix A. Specifications
CSIII (MODEL 4310B) USER’S GUIDE Appendix A. Specifications For latest product specifications, see product data sheet DS00003499. ALARM INTERFACE The main advantage of employing CPT is it allows the use of low power lasers allowing to construct low power, small size atomic clocks.Alarm (relay): DB9 female (Rear panel). - Page 38 CSIII (Model 4310B) User’s Guide NOTES: DS50003057A-page 38 2021 Microchip Technology Inc.
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Page 39: Appendix B. Programmer's Guide
Note that this section is designed for experienced programmers and assumes a general knowledge of RS-232 interface programming. GENERAL PARAMETERS The CsIII’s factory-default RS-232 settings, modifiable using the C05 command, are as follows: • Configuration: DTE • Data Bits: 7 •... -
Page 40: Cesium Command Reference
All entries in the data field are left justified, and the remainder (if any) of the data field must be filled in, to round it up to 9 characters in length. All commands sent to the CsIII return a response of the form <STX><Text of response><ETX>... - Page 41 Reserved for factory use — Arm 1PPS Sync circuit. Issue this command after connecting a No data required 1PPS source to the CsIII. The sync remains armed for 3 seconds Return variables (250 characters) No data required Return constants (145 characters) —...
- Page 42 CSIII (Model 4310B) User’s Guide TABLE B-3: CSIII COMMAND REFERENCE Description Data Field Reserved for factory use — Reserved for factory use — Reserved for factory use — Reserved for factory use — Reserved for factory use — Reserved for factory use —...
- Page 43 182 - 187 +15.1V Space 188 — — –15.5 V power supply 189 - 194 –16.2V Quartz oscillator cold/warm 196 - 198 Space 199 — — Cesium oven supply voltage 200 - 205 F008.0 2021 Microchip Technology Inc. DS50003057A-page 43...
- Page 44 CSIII (Model 4310B) User’s Guide TABLE B-4: DATA RETURNED BY THE “RETURN VARIABLES” COMMAND D*1 (CONTINUED) Variable Field Example Space 206 — — Mass spectrometer voltage 207 - 212 VS18.9 Space 213 — — Cesium beam tube Ionizer voltage 214 - 219 VF1.05...
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Page 45: Event Log
The event log can be cleared by an external command. Because the CsIII lacks a battery backed up real time clock, the Event log stores two distinct timestamps. The first is a 6 byte calendar date; the second is a 32-bit value representing the total system power on hours. - Page 46 CSIII (Model 4310B) User’s Guide NOTES: DS50003057A-page 46 2021 Microchip Technology Inc.
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Page 47: Appendix C. Customer Assistance/Technical Support
CSIII (MODEL 4310B) USER’S GUIDE Appendix C. Customer Assistance/Technical Support Microchip backs its products with various support services including Customer Service, Customer Technical Support Center, a website, electronic mail, and global sales offices. This appendix contains information about contacting Microchip using these support services. - Page 48 CSIII (Model 4310B) User’s Guide NOTES: DS50003057A-page 48 2021 Microchip Technology Inc.
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Page 49: Worldwide Sales And Service
New York, NY Tel: 46-31-704-60-40 Tel: 631-435-6000 Sweden - Stockholm San Jose, CA Tel: 46-8-5090-4654 Tel: 408-735-9110 UK - Wokingham Tel: 408-436-4270 Tel: 44-118-921-5800 Canada - Toronto Fax: 44-118-921-5820 Tel: 905-695-1980 Fax: 905-695-2078 DS50003057A-page 49 2021 Microchip Technology Inc. 02/28/20...
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