Validation of Time Synchronization

beiwei5du

Validation of TimeSynchronization
时间同步性验证


补充内容 (2017-1-12 21:33):
是否买电波钟（ridio-controlled clock）就不需要进行相应的定时校准呢？？？另一个问题，安装电波钟在洁净区的电波信号接收是否有问题？？？是否还需要其他措施辅助？？？

beiwei5du

非常好的一篇文章！

dingkaiwang

果然是好资料

syhorchid

学习一下

beiwei5du

是否买电波钟（ridio-controlled clock）就不需要进行相应的定时校准呢？？？另一个问题，安装电波钟在洁净区的电波信号接收是否有问题？？？是否还需要其他措施辅助？？？@江苏新征鸿净化 @石头968

beiwei5du

有没有防爆型的电波钟推荐（用在化工生产场所）？？？？？

石头968

beiwei5du 发表于 2017-1-12 21:33
是否买电波钟（ridio-controlled clock）就不需要进行相应的定时校准呢？？？另一个问题，安装电波钟在洁净 ...

自动接收无线电标准时间信号，所以不用校准。
信号不好的话，可能更不准。
这个应该和收音机一样信号一样吧，越远信号越差，信号是不是能够被彩钢板屏蔽，是否需要信号放大器，这个我也不知道啊。

beiwei5du

石头968 发表于 2017-1-12 22:02
自动接收无线电标准时间信号，所以不用校准。
信号不好的话，可能更不准。
这个应该和收音机一样信号一 ...

现在有提到使用手机对时（手机的SIM卡时间同步cell phone network），但是但是手机上的时间可以设置的呢？？这个权限如何进行控制的呢？？
One option that’s less expensive is to install an NTP timeserver that gets its time signal from the cell phone network. The cells in a digital phone network [e.g., Code Division Multiple Access (CDMA)] must be kept within a certain level of accuracy or the phones in the network won’t work correctly. To achieve the required accuracy, most digital phone towers are kept within ± 10 microseconds (± 0.000 010 seconds). A typical digital phone signal receiver could also provide reasonable accuracy as an NTP timeserver. This is shown in Figure 7.

beiwei5du

石头968 发表于 2017-1-12 22:02
自动接收无线电标准时间信号，所以不用校准。
信号不好的话，可能更不准。
这个应该和收音机一样信号一 ...

不知道现在是否有其他企业在洁净区是如何做到时间同步的呢？？按照最原始的定期校准？？？还有关于现在的设备（单独），在其要求的时间同步方面是如何解决的呢？？现在我们有多台纯化水分配系统，每台的时间都会存在较大的便宜！！

beiwei5du

选自https://www.greyware.com/software/domaintime/v5/installation/regulatory-fda.asp

U.S. Food and Drug Administration

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The U.S. Food and Drug Administration (FDA) has adopted wide-ranging regulations governing activities in the life sciences industry. Among these are regulations regarding the use of electronic records and electronic signatures, contained in 21 CFR Part 11 of the Federal Register.

Implicit in these regulations is the expectation that systems used in producing electronic records or signatures must have the correct date and time so that time stamps produced are correct and verifiable. Extracts of the applicable sections of the Rule, current FDA Guidance to Industry memos, as well as relevant commentary from private industry that help define the time stamp requirements follow.

21 CFR Part 11 Final Rule, March 20, 1997 Section 11.10 Controls for closed systems specifies:



"(e) Use of secure, computer-generated, time-stamped audit trails to independently record the date and time of operator entries and actions that create, modify, or delete electronic records. Such audit trail documentation shall be retained for a period at least as long as that required to for the subject electronic records and shall be available for agency review and copying."

Draft Guidance for Industry on Part 11, Electronic Records, Electronic Signatures - Scope and Application:


Section III. C. 2. Audit Trail
"Even if there are no predicate rule requirements to document, for example, date, time, or sequence of events in a particular instance, it may nonetheless be important to have audit trails or other physical, logical, or procedural security measures to ensure the trustworthiness and reliability of the records."

Draft Guidance for Industry: Computerized Systems Used in Clinical Trials:


IV. Standard Operating Procedures, Data Entry, Section B. Electronic Signatures
"2. Personnel who create, modify, or delete electronic records should not be able to modify the audit trails."
"5. Audit trails should be created incrementally, in chronological order, and in a manner that does not allow new audit trail information to overwrite existing data in violation of §11.10(e)."IV. Standard Operating Procedures, Data Entry, Section C. Date/Time Stamps
"1. Controls should be in place to ensure that the system's date and time are correct."
"2. The ability to change the date or time should be limited to authorized personnel and such personnel should be notified if a system date or time discrepancy is detected. Changes to date or time should be documented."



Summary of Requirements
Four basic requirements regarding time synchronization for FDA regulatory purposes can be derived from the above:

• Time and Date on Systems Must Be Correct
  Standard best practices to ensure the time and date on all computer clocks is correct is to verify they are reliably synchronized to a commonly used time standard, such as provided by the National Institute of Standards and Technology (NIST) or United States Naval Observatory (USNO) atomic clocks, or Stratum 1 time sources such as GPS receivers.
  
• Ability to Change the System Clock Must Be Restricted
  Users must not be allowed to change the time on systems at will.
  
• Alerts to System Date/Time Discrepancies Must Be Generated
  Administrators must be notified immediately of problems with the time on systems.
  
• An Audit Trail to Demonstrate the Validity of Time Stamps Must Be Maintained
  The accuracy of the date/time used to produce time stamps is integral to proving the trustworthiness and reliability of all electronic records and signatures. Non-modifiable records of the generation of time stamps (including the time synchronization process) are essential.
  

How to Use Domain Time II to comply with the FDA 21 CFR Part 11 Requirements

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Domain Time II meets or exceeds all of the guidance and directives detailed above. Properly configured, Domain Time will allow you to easily comply with all current and proposed requirements to assure the validity of the date and time of time stamps and related audit requirements.

Domain Time II is designed specifically to provide both accurate time synchronization and a complete history of that synchronization. Each Domain Time II time sync component (Servers and Clients) have the ability to keep detailed logs and statistics of their own activity - and, critically, to report that information automatically to monitoring and auditing systems when requested.This diagram shows the basic structure of the Domain Time II system, showing how time synchronization and audit data collection are handled.

Configuring for compliance
These are the steps necessary to use Domain Time II to assist in compliance with FDA 21 CFR Part 11:


• Requirement: Time and Date on Systems Must Be Correct
  Solution: Configure Domain Time II to provide accurate time sync to all clocks
  Domain Time II, when installed according to the instructions found on the Recommended Configurations page of the Domain Time II documentation, will meet the FDA 21 CFR Part 11 requirements for time synchronization. However, there are a few additional configuration considerations beyond the standard recommend installation instructions for FDA 21 CFR Part 11 compliance.
  
  

  Required Configuration Change
  

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  Set the Domain Time II Master to use NIST, USNO, or other reliable Stratum 1 system as its time source:
  Use the Time Sources tab page of the Domain Time II Server Control Panel Applet to include any of the following entries in the Sources fields (in any order):
  

  • time.nist.gov
    
  • ntp2.usno.navy.mil
    
  • The IP address or DNS name of a Stratum 1 source, such as GPS receiver
    
    

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• Requirement: Ability to Change the System Clock Must Be Restricted
  Solution: Domain Time II Server and Clients have a function called Clock Change Monitor that prevents users without administrative rights from changing the time on their systems. This function is enabled by default. No additional configuration is necessary.
  
  
• Requirement: Alerts to System Date/Time Discrepancies Must Be Generated
  Solution: Use Domain Time II Audit Server (see below) or Monitor Service to provide alerts when time variance on systems exceeds the thresholds you set.
  
• Requirement: An Audit Trail to Demonstrate the Validity of Time Stamps Must Be Maintained
  Solution: Use Domain Time II Audit Server to collect and preserve tamper-proof audit records
  
  Domain Time II has exceptional built-in functionality to easily and automatically provide an audit trail of time synchronization. The following steps will provide unimpeachable records of the state of time synchronization. You will know exactly when your changed, why, when, and with whom they synchronized.
  
  
  
  
  • Set Reference Clock and System Alerts.
    Domain Time II Audit Server has the capability to generate alerts when any monitored system's variance from a reference clock exceeds a threshold you set. Warning entries of these events are also included in the logs.
    
    
    Reference Clock
    Audit Server can compare the sampled time of any audited machine to a reference clock. The reference clock's time is used to calculate certain variances and alerts. By default, Audit Server automatically locates the nearest Domain Time II Server to use as its reference clock. Since OATS specifies that variances by shown in relation to NIST, the reference clock setting must be changed.
    Alert Thresholds
    Audit Server has the ability to generate an alert if the time variance on any system exceeds a particular threshold. The OATS-specified requirement is that the log for any machine drifts outside 3 seconds from NIST time should include a notice to that effect. Audit Server will automatically add a warning to the log when any machine exceeds the Any machine time off by... setting on the Audit Server Alerts & Logs tab page.
    
    

    Required Configuration Changes to Audit Server
    

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    Set the Reference Clock to NIST: Go to Audit Server's Advanced tab and change the Reference Clock setting to usetime.nist.gov (note, you must have the NTP port 123 UDP open on your firewall to allow Monitor to contact the NIST time server).Set the Alert Threshold: On Audit Server's Alerts & Logs, make sure the Any machine time off by setting is set to 3 seconds.
    

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  • Set Audit Record Collection and Retention Options
    Use Domain Time II to collect audit data and archive as necessary.
    
    
    The Domain Time II Audit Server automatically collects detailed time synchronization data from the network. Data can be kept in local storage for the required three year period, or archived off to permanent offline storage as necessary.
    
    
    
  • Document procedures
    Use Domain Time II documentation as necessary to write your procedures and as a baseline for your "black box" system validation testing.
    
    
    Domain Time II is thoroughly documented, and the behavior of the Domain Time II system and each time component and how it synchronizes is detailed in the Technical Information and Configuration and sections of the online documentation. These documents can be used to provide any level of detail of the system operation for compiling your documented procedures.
    In particular, the Resource Impact Statement contains a great deal of useful material as a starting point for "black box" testing of Domain Time II for use on your validated systems.
    
    
    
  • Optional: Keep Detailed Logs of every time a clock is synchronized and the results of that synchronization
    Use Domain Time II Audit Server to collect the synchronization logs of all machines.
    
    
    See the Audit Server documentation for details on configuring and using Audit Server.
    Domain Time II Audit Server is capable of collecting a log of time sync activity from Domain Time II components into a central location for easy analysis and archiving. Information retrieved includes when a sync occurred and with whom the component synced, and amount the clock was corrected. Log retention is configurable to match archival schedules.
    Audit Server also keeps an audit record which can be used to demonstrate on-demand that any particular machine was synchronized, with what source, and with what accuracy.
    Domain Time II Server and Client also keep a local log that includes not only time sync events, but all other events activity and events by the component. These logs can be manually collected and archived to meet the log retention requirements, however doing so is typically much more complex than using Audit Server to do so, and results in significantly larger log files to be archived. In most cases, using Audit Server to collect sync logs is optimal.
    
    

    Required Configuration Changes to Audit Server
    

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    See Audit Server documentation for configuration details.

    
    

References
21 CFR Part 11 Final Rule, March 20, 1997
Draft Guidance for Industry on Part 11, Electronic Records, Electronic Signatures -
Scope and Application, February 2003
Guidance for Industry: General Principles of Software Validation;
Final Guidance for Industry and FDA Staff, January 11, 2002
Guidance for Industry: Computerized Systems Used in Clinical Trials, April 1999

Disclaimer
This document is provided for informational and planning purposes only. The information used in compiling this document was obtained from publically available sources and no representation is made as to the accuracy of the information, nor as to the accuracy of any reading or interpretation thereof. No warranty is made or implied regarding the usefulness or suitability of this information for a particular purpose. Further, Greyware Automation Products, Inc. is not liable for any damages, real or consequential, arising from use of this information.

静水蓝心

太高大上了

beiwei5du

以后车间上这种同步时钟系统还是很有必要的呢！！

Synchronized Digital Clocks

Description : STYRAX manufacturers’ digital synchronized master clock systems, and other LED clocks. All clocks can display the same, accurate, legal time. STYRAX commercial digital clocks are specifically designed for applications where precision and reliability are of utmost importance. These clocks may be used as accurate stand-alone time displays. They can also be synchronized so that all clocks display the same time. SDC105M clock synchronizes the Slave Clocks (i.e.SDC1051S, SDC1052S) every second within the RS485 network. MASTER CLOCK FEATURES & SPECIFICATIONS STYRAX Synchronized Master Clock 6-digit IP LED Synchronized Master Clock effortlessly put everyone on the same time. These revolutionary clocks display seconds in a smaller height than the hour and minutes so the clocks are highly readable, even from long distances. It can communicate real time data synchronously up to 32-Slave clocks. Master clock operates with highly stable and accurate time, which in turn gives the accurate real time through out the Network. KEY FEATURES OF MASTER CLOCK Advanced Microcontroller Based Master clock Reliable LED display High readability Synchronizes Slaves Every Second Specially Designed for Clean Room Environment Flicker-free Bright Red Seven Segment LED Display User friendly programming modes Instruments with password protection Lithium Battery ensures correct time after power failure. Time Displays in 24 Hrs Format (HH:MM:SS) Red filter Transparent overlay facilitates Wide Viewing Angle Drives up to 32 Slave Clocks. Interface communication: RS485 Model No SDC105M Display Two 0.8” Red Seven Segment LED to Display ‘Hours’ Two 0.8” Red Seven Segment LED to Display ‘Minutes’ Two 0.5” Red Seven Segment LED to Display ‘Seconds’ Accuracy ±2 minute per Year @ 25° C Communication RS 485 (3 wire) Time Setting Through Key Pad Controller Built in Embedded with Industrial performance Time Format 24 Hrs Mode Environmental Ratings Operating Temperature : 0 - 50 C Mechanical Dimensions : See the mechanical Drawings Weight : 0.8 Kg (Approx) Face plate : Flush Mounting SS 304 Enclosure material : Mild Steel Mounting        Brick wall concealed mounting, Modular wall mounting Operating Voltage 220V, 50 Hz, ± 5 %, 25 W APPLICATIONS: The following are the main application areas where synchronized digital clocks play an important role. Pharmaceutical industries Process Industries Warehouse Railways Mass Production Factories Conference halls Examination Halls Colleges etc Slave Clock (1 inch) STYRAX manufacturers’ digital synchronized clock systems, and other LED clocks. All clocks can display the same, accurate, legal time. STYRAX commercial digital clocks are specifically designed for applications where precision and reliability are of utmost importance. These clocks may be used as accurate stand-alone time displays. They can also be synchronized so that all clocks display the same time. SDC1051S series of clocks are synchronized every second with master clock on RS485 network. Even if network failure they operate with in built real time clock. KEY FEATURES OF SLAVE CLOCK Reliable LED display High readability One-second synchronization with master clock. Works in stand – alone mode if network failure Specially Designed for Clean Room Environment Flicker-free Bright Red Seven Segment LED Display Lithium Battery ensures correct time after power failure. Displays time in HH:MM Format Red filter Transparent overlay facilitates Wide Viewing Angle Interface communication: RS485 Indication of network failure with blinking display with time Model No SDC1051S Display "0.8” Seven Segment LED Display (Red) (For Hrs Mins & secs) Two 3mm flashing LED’s indicates seconds count Accuracy Depends on master clock Communication RS – 485 Time Master Clock time/Programmable quartz clock with internal battery backup (At least once time need to be updated by master) Controller Built in Embedded with industrial performance Operating voltage 220 Volts AC 50 Hz, 10VA Time Synchronization Every second Time Format 24 hour mode Power Consumption 25W Environmental Ratings Operating temperature: 0 - 50°C Mechanical Dimensions: 110x72x33.5mm. Weight:0. 5kg (Approx) Faceplate: Flush mounting SS 304. Enclosure type: MS Siemens gray powder coated Mounting 1) Brick wall concealed mounting/wall mounting. 2) Modular wall mounting APPLICATIONS : The following are the main application areas where synchronized digital clocks play an important role. Pharmaceutical industries Process Industries Warehouse Railways Mass Production Factories Conference halls Examination Halls Colleges etc Slave (2 inch) STYRAX manufacturers’ digital synchronized clock systems, and other LED clocks. All clocks can display the same, accurate, legal time. STYRAX commercial digital clocks are specifically designed for applications where precision and reliability are of utmost importance. These clocks may be used as accurate stand-alone time displays. They can also be synchronized so that all clocks display the same time. SDC1052S series of clocks are synchronized every second with master clock on RS485 network. Even if network failure they operate with in built real time clock. KEY FEATURES OF SLAVE CLOCK Reliable LED display High readability One-second synchronization with master clock. Works in stand – alone mode if network failure Specially Designed for Clean Room Environment Flicker-free Bright Red Seven Segment LED Display Lithium Battery ensures correct time after power failure. Displays time in HH:MM Format Red filter Transparent overlay facilitates Wide Viewing Angle Interface communication: RS485 Indication of network failure with blinking display with time. SPECIFICATIONS & FEATURES : Model No SDC1052S Display 2” Seven Segment LED Display (Red) (For Hrs & Mins) Two 5mm flashing LED’s indicates seconds count Accuracy Depends on master clock Communication RS – 485 Time Master Clock time/Programmable quartz clock with internal battery backup (At least once time need to be updated by master) Controller Built in Embedded with industrial performance Operating voltage 220 Volts AC 50 Hz, 10VA Time Synchronization Every second Time Format 24 hour mode Power Consumption 25W Environmental Ratings Operating temperature: 0 - 50°C Mechanical Dimensions: 380x120x40mm. Weight: 2 kg (Approx) Faceplate: Flush mounting SS 304. Enclosure type: MS Siemens gray powder coated Mounting 1) Brick wall concealed mounting/wall mounting. 2) Modular wall mounting APPLICATIONS : The following are the main application areas where synchronized digital clocks play an important role. Pharmaceutical industries Process Industries Warehouse Railways Mass Production Factories Conference halls Examination Halls Colleges etc

胜利者

高大上

石头968

beiwei5du 发表于 2017-1-12 22:14
现在有提到使用手机对时（手机的SIM卡时间同步cell phone network），但是但是手机上的时间可以设置的呢 ...

手机和电脑一般不调整时间，设置开机自动同步时间，比较准的。

石头968

beiwei5du 发表于 2017-1-12 22:18
不知道现在是否有其他企业在洁净区是如何做到时间同步的呢？？按照最原始的定期校准？？？还有关于现在的 ...

定期检查、校准，拿一个对过时间的手机或者手表，去车间挨着对时调整，做好记录就可以了吧，不用太繁琐。

石头968

beiwei5du 发表于 2017-1-12 23:18
以后车间上这种同步时钟系统还是很有必要的呢！！

KEY FEATURES OF MASTER CLOCK

最好是全车间上一套网络同步时间显示装置，各地自动显示同步时间。

w88811216

好东西，谢谢分享！