User manual AMX I!-TIMEMANAGER

[. . . ] GOVERNMENT RESTRICTED RIGHTS The SOFTWARE and documentation are provided with RESTRICTED RIGHTS. Use, duplication, or disclosure by the Government is subject to restrictions as set forth in subparagraph (c)(1)(ii) of The Rights in Technical Data and Computer Software clause at DFARS 252. 227-7013 or subparagraphs (c)(1) and (2) of the Commercial Computer Software--Restricted Rights at 48 CFR 52. 227-19, as applicable. Manufacturer is AMX Corporation, 3000 Research Drive, Richardson, TX 75082. If you acquired this product in the United States, this Agreement is governed by the laws of the State of Texas. [. . . ] You may get a copy of this file from the /pub directory on any NIST timeserver. If this file cannot be found on the NetLinx file system, a default list of NIST servers will be used instead. See the NIST home page at http://www. boulder. nist. gov/timefreq/index. html for more information on NIST Time service or Servers. Additionally, i!-TimeManager has also been written to use a "popular" DayTime format which is used by the Linux implementation of DayTime and Tardis, a popular time syncing software. Although not specified, the Date and Time of this format does not specify the time zone and is assumed to be local. If you select DayTime protocol and select a server that is running DayTime and the format, specifically "DayOfWeek Month Day HH:MM:SS Year", can be found, no time offset will be added. If you have chosen this combination and find that the time does not synchronize to the correct time, choose another protocol or server. i!-TimeManager 3 Time Protocols Time Protocol The Time protocol, based on RFC868, is a very simple straightforward time protocol providing the number of seconds that have transpired since January 1, 1900 UTC. However, the number of seconds in this protocol is provides as a 32 bit unsigned number, which can represent a maximum value of 4294967295 (2 ^ 32). 4294967295 seconds from January 1st, 1900 occurs on Feb 7, 2036 at 6h 28m 16s. Therefore, this protocol can only accurately represent time before this date. Many of the NIST servers, as well and many Unix, Linux and Windows programs, can provide this time protocol, and it can be reliably used up until Feb 7, 2036. SNTP Protocols The last two Time protocols share the same message format but differ in their connection scheme. SNTP stands for Simple Network Time Protocol, a subset of NTP or Network Time Protocol, is based on RFC2030. It is a highly accurate measure of time and date and also measures Date and Time as the number of seconds from January 1st 1900. However, the number of seconds is provided in two parts: the number of whole seconds, with a range of 4294967295 (2^32) and fractions of a second also with a range of 4294967295 (2^32). The Netlinx Master is not able to take advantage of the fractions of a second offered by SNTP and therefore has the same accuracy as the Time protocol but SNTP also provides information about the integrity of the data supplied. RFC2030, which defines the SNTP protocol, has also made a provision for Dates and Time after Feb 7, 2036. SNTP message can represent a Date and Time accurately until some time in the year 2104. Most of the NIST servers also provide Date and Time information in SNTP format. The difference between SNTP (123/udp), SNTP Broadcast (123/udp) is simply one of connection. It is possible to configure an SNTP server to broadcast the time in SNTP format to an entire network or node of a network. i!-TimeManager can be configured to actively retrieve the time in SNTP format from an SNTP server (protocol number 3) or simply listen for SNTP broadcasts on the network (protocol number 4). Although SNTP broadcasting may sound like an ideal solution for Date and Time information, the Network Administrator should make this decision. Choosing a Protocol So why did we implement so many time protocols? [. . . ] If left blank (empty string), a default server will be picked from the nist-srv. lst file location in the doc:\time directory of the NetLinx Master. If this file is not present, an internal list of NIST time server will be used, and an appropriate server will be selected from the list. Channels i!-TimeManager uses a virtual device to post channel events for certain time related activities. i!-TimeManager supports the following channels: i!-TimeManager Channels Channel 1 2 3 4 Description Sunrise Occurred Sunset Occurred Daylight Saving Time is active. Time changed by Internet time server. Commands i!-TimeManager supports the following commands. [. . . ]