Did You Know?

New US Daylight Savings Time Rules May Require Adjustment of AMX Controllers

 

Previous to 2007, Daylight Savings Time (DST) began for most of the United States at 2:00 a.m. on the first Sunday of April and reverted back to standard time at 2:00 a.m. on the last Sunday of October.

Per the The Energy Policy Act of 2005, effective in 2007, daylight savings time has been extended one month. The new schedule is: 

• DST begins at 2:00 a.m. on the Second Sunday in March (1st Sunday on or after March 8th)
  

• DST ends at 2:00 a.m. on the First Sunday of November.
  

How will this change affect AMX controllers programmed to automatically adjust via the old rules?

Because most programs were written before the US Congress decided to change the rules, AMX controllers programmed to automatically adjust via the old rules will not adjust the time at the appropriate times per the new rules. However, AMX master controller TIME may be adjusted manually and new daylight saving time rules may be applied.  

Note: This may be an irrelevant issue if a program contains no time dependencies.

 

Adjustments For NetLinx Systems:
NI-700/900, NI-2100/3100/4100, NXC-ME260/64

These masters are upgradeable to Duet Master Firmware version 3.21 or greater which allows daylight savings rules to be defined and changed via web browser by connecting to IP address or URL of master.

User Manuals for these devices describe the process in more detail.  Set the rules to begin at 2:00 a.m. on the Second Sunday in March (1st Sunday on or after March 8th) and to end at 2:00 a.m. on the First Sunday of November.

If these masters contain code driven daylight savings time rules, like DAYLTSAV system call, SunriseSunset.axi, or the i!TimeManager module, the code would need to be recompiled and downloaded with the old code driven rules modified or removed.

 

Adjustments For Other NetLinx Masters

For Non-duet masters and masters which are not NI-700/900, NI-2100/3100/4100, or NXC-ME260/64, programmers typically used the DAYLTSAV system call, SunriseSunset.axi, or the i!TimeManager module when applying auto-adjust features for daylight savings time.

In these cases, the code would need to be recompiled and downloaded with the old code driven rules modified or removed.

For more information, please consult the Original TechNote released November 17, 2006.