Network Time Protocol Client

Introduction

Sierra Chart has an advanced Network Time Protocol implementation to synchronize your local computer clock to a highly accurate network time protocol server which references an atomic clock.

This feature is used to ensure your clock is within milliseconds, of the actual time.

The time zone setting on your computer is properly considered when the time is being set. However, it is critical that the time zone setting on your computer is set correctly. For instructions to do that, refer to Setting Computer System Date-Time and Time Zone.

Usage

Follow the below instructions, to enable the NTP Client in Sierra Chart, to use the Sierra Chart provided NTP server which is synchronized from a time server in the data center using a GPS signal.

1. Update Sierra Chart to the current version. Refer to the Fast Update instructions.
2. Select Global Settings >> NTP Settings.
3. Press the Reset button.
4. In the NTP Servers listbox, choose the server with the name "Sierra Chart US Midwest". This is ntp_usmw.sierrachart.com:11497.
5. Set Individual Server Polling Interval (Seconds): 30.
6. Set Number of Responses to Wait for to Update Time: 1.
7. Set Minimum Number of Responses to Wait for to Update Time: 1.
8. Set Time Delay After Last Received Response to Update Time if Insufficient Responses (Seconds): 5.
9. The other settings are irrelevant and not implemented.
10. Press Apply All.
11. The Last Offset Value field, shows the time adjustment that was done to your local clock, and the Date-Time it was last done.
12. Press Cancel, since the settings were previously applied.
13. Detailed information about the setting of the Date-Time is provided in the Window >> Message Log.

Settings

The following settings are available:

• NTP Client Enabled: When this is set to Yes then the NTP Client s enabled and will adjust the local computer clock based upon the settings in this window.
• NTP Client working Status: This is not currently implemented.
• NTP Servers: This is a list of NTP servers that you can choose from to synchronize from. They are based upon geographical location. In the list, there are single servers, and groups of servers. Most of them are groups of servers (Usually 4 servers). One of them is also the Sierra Chart NTP server which we have in the United States in the Midwest. It is a highly accurate time source.
• [Add] button: Enter a new NTP server or list of servers in the Servers to Add edit box and then press the [Add] button to add that NTP server or servers to the list.
• [Remove] button: Select an NTP server in the NTP Servers list and then press the [Remove] button to remove that NTP server from the list.
• [Reset] button: Select this button to reset the list of NTP Servers to the default.
• Servers to Add: This is used with the [Add] button.
• Individual Server Polling Interval (Seconds): This sets the time in seconds to request the time from from the selected NTP server or servers. For the Sierra Chart server, you can make this as low as 15 seconds. For other servers we do not recommend using a time less than 60 seconds. If it is too low, the server you will give a KOD packet causing Sierra Chart to slow the request rate even lower than what is specified here.
• Number of Responses to Wait for to Update Time: Normally this should be set to the number of servers in the group of servers you have selected. Set this to 1 if there is only a single server.
• Minimum Number of Responses to Wait for to Update Time: Normally this should be set to 50% of the number of servers in the group of servers you have selected through the NTP Servers setting. If there is only a single server, like in the case of the Sierra Chart NTP server, then set this to 1.
• Time Delay After Last Received Response to Update Time if Insufficient Responses (Seconds): Normally set this to 5 seconds. If the NTP Servers setting is set to a group of servers and in that group there are 4 servers (as an example) but only 2 responses are received and that is a sufficient number of responses based on Minimum Number of Responses to Wait for to Update Time, then after this time delay (b>Time Delay After Last Received Response to Update Time if Insufficient Responses), the responses will be processed.
• Threshold Level in Milliseconds for Increasing/Decreasing Polling Interval: This is not currently implemented.
• Number of Clock Adjustments to Determine Automatic Adjustment: This is not currently implemented.
• Last Offset Value: This is a read-only field that displays the last offset value that was used to adjust the local computer clock.
• Peers Info: This shows, the information from the group of NTP servers being polled for time updates.
• Has Privilege to set System time: This will be Yes if Sierra Chart has the privilege to adjust the system time. If it is No, then refer to Operating System Privileges for Setting Time.

Additional Implementation Notes

The Network Time Protocol client in Sierra Chart is based upon RFC 4330 (Simple Network Time Protocol).

However, Sierra Chart uses multiple NTP peers at the same time using the UDP protocol. The reason for this is that the connection to a single peer may not be fast or stable or there may not be a symmetric time between sending and receiving.

By using multiple peers, Sierra Chart is able to determine the correct offset value to correct the system clock. The more NTP peers that Sierra Chart connects to, means a more accurate offset value for correcting the system clock.

However, when using the Sierra Chart provided NTP server, only a single NTP server is used in this case and it is sufficient because it is a highly reliable time source.

Operating System Privileges for Setting Time

Your computer and network need to be allowed to communicate over NTP (Network Time Protocol) UDP port 123 for NTP to function properly.

In Global settings >> NTP Settings, if NTP Client Working Status: shows "Not Working. No privilege to adjust system time.", then this means Sierra Chart does not have the necessary operating system privileges to set the system clock. You will need to set Sierra Chart to run with administrator level access (explained below).

To set Sierra Chart to run with administrator level access, go to the folder that Sierra Chart is installed to. Right-click on SierraChart.exe and select Properties. Select the Compatibility tab. Enable the option Privilege Level >> Run This Program As an Administrator. After this you will need to restart Sierra Chart.

Alternatively, exit from Sierra Chart and right click on the icon used to start Sierra Chart on your desktop and select Run as Administrator.

Suppressing NTP Messages in Message Log

When the Network Time Protocol (NTP) client is working and requesting timing data from NTP servers and adjusting the local computer clock, there are messages added to the Window >> Message Log for the activities of the NTP client.

To prevent these messages from being displayed in the Message Log, select Global Settings >> Message Categories.

Set NTP Info to No and press OK.

Computer clocks do not usually maintain accurate time. If the NTP Polling Interval is set to 60 seconds, it is not unusual for there to be adjustments to your local clock, every minute, of an amount less than 10 ms each time.