For those who want to make their own tools, adjusting the HP-clock.
The following library commands from ClckAdjst are accessible via [LS] [2]. Depending on the personal configuration it might be required to page through the Library catalog with the [NXT]-key.
AutomaticADjustment: AAD takes its input from a list named MCL (Memory for the CLock). This list need to be stored in the Home directory. The content of the list will be initialized by running ClSet (Clock Setup). A few days later the clock need to be calibrated with the commands in ClMen (Clock Menu). The information about the calibration will be stored in MCL, too. After the above mentioned procedure AAD will adjust the clock when it is called. For the hp 49g+ the adjustment procedure is a bit tricky, because the clock canot be adjusted better than +/-1 s. The hp 49g+ clock will be adjusted only for full seconds and a "virutal" time of this adjustment will be calculated and stored, which improves the accuracy of the procedure.
With activated automatic DST (daylight saving time), set by calling ClSet or later within ClMen, the programm AAD applies to timezones from -10 to -5 the US-rule for daylight saving time switches. For timezones from -1 to 3 the european rule is applied.
DST US-rule: The switch to DST is defined to be on the first Sunday in April at 2:00 h am local time. The switch from DST to "normal" time is defined to be on the last Sunday in October at 2:00 h am local time. Indiana and the Mountain Region do not apply DST.
DST European-rule: The switch to DST is defined to be on the last Sunday in March at 1:00 h UT. The swicht from DST to "normal" time is defined to be on the last Sunday in October at 1:00 h UT.
In the US the changes will be applied to the timezones one after the other, from the east to the west. In Europe all states apply the change at the same moment.
Assuming, your HP-clock is already adjusted better than 2.5 s. Start A&TS when your accurate reference clock just switches in steps of 5 seconds. It calculates the required adjustment, puts the time string (when pressed) into stack level 1 and the required adjustment into stack level 2. The routine A&TS is used when pressing the soft key dNOW-> in ClMen (ClockMenu). A&TS is a powerfull tool for synchronisation of the HP-clock with the reference clock. Using A&TS several times and calculating the average will give a more accurate deviation between the HP-clock and the reference clock. To adjust the HP-clock use the lib-command sADJ->. With the hp 49g+ a virtual adjustment time will be created (s. AAD).
Recalls the ClockMenu. The ClockMenu helps to handle time zone changes, changes from or to the daylight saving time, switch between automatic and manual daylight saving time changes, helps for the calibration of the system clock and gives information about the initial setting, last adjustment, actual time zone and actual daylight saving time mode.
Recalls the ClockSetup. Calling ClSet an inform-box is shown on the display to apply initial clock settings. The user will define the time zone and whether daylight saving time is valid.
Recalls the Inform-Box for Changing the Time Zone and the daylight saving time.
Displays the TimeZone, the rule for daylight saving time (EU for Europe, US for United States or NN for Not Named), the mode (auto DST or manual DST) and if daylight saving time is active.
Attention, this command is very powerful and influences the sensitivity for further "improved" calibrations of the HP-clock.
Takes days from stack 1 and initialises clock adjustment to the date days before running ClIni. Zero on stack 1 would set the init-time to the time when ClIni has been called and would set seconds per day (spd) to zero. This is recommended for a new setup. E.g. 1 on stack 1 would keep the current spd and set the init-time to one day before running ClIni. The number of days influences the sensitivity for further adjustments. For small number of days the sensitivity will be big, means adjustments with ->sADJ will have a bigger influence on spd (seconds per day), which is used by AutoADjustments (AAD) in the future.
Displays the init-time and the time for the last automatic adjustment. Time zone and DST-mode will be displayed, too.
Gives version number and e-mail address for help from the author.
Takes the required adjustment (in seconds) from the stack level 1 and adjusts and calibrate the HP-clock.
Calculates the required adjustment in seconds per day from the MCL list.
Attention, this command is very powerful and influences the HP-clock, when running AAD. Takes the required adjustment in seconds per day from stack level 1, and updates MCL for further adjustments with AAD (s.a.). spdA has no effect in case the init-time is equal to the last adjustment time.