For the record: The Chronos does not flash at time control. You might be thinking of the Excalibur Game Time II.
The Chronos stops at 0:00 for the side that flagged. It does not “run negative,” and there is no way for a player to “unflag” in an increment control. In some modes—those with more than one time control for a game—three horizontal bars are shown on the display along with 0:00.
The user options are whether to set “halt at end,” “beep at end” and “beep at time control,” for modes with more than one control.
The beeps are self-explanatory. Halt-at-end means that once one player flags, no time runs off his opponent’s clock. It prevents both sides from running out of time, a la the old both-flags-down draws from the early days of SD rated games played with analog clocks.
Per the 5th Edition and the Rules update doc:
The beep-at-end option should be enabled. Whether beep at time control should be enabled is not clear.
Halt-at-end should ‘not’ be enabled in increment games. It is not clear what is preferred for non-increment games.
The 4th Edition, in the infancy of delay-digital clocks—and back when USCF wanted to corner that market—stated that “flag substitutes” and halt-at-end were “both legal and highly desirable” for the reasons some have outlined here. (Mainly that a clock is objective and equal footing for both players.)
And I really do ‘get’ those reasons…but the more I think about it, the more I like the idea that a digital clock is just that: a clock. It is preferred for SD games because of its delay/increment capability and perhaps its precision.
I believe this statement is only true for the sudden death time control and that in others it adds the time allotment of the next control. Correct me if I’m wrong as I’m not a Chronos owner.
You are correct, Harold. I should have clarified that I referred to the ultimate or final time control. Just when a guy thinks he knows his chess clock cold…will play around some more tomorrow and report back if we unearth new nuggets.
It depends, also, on whether the move counter is set.
If the control is 40/90, then SD/60, and the move counter is not set, then as soon as the time reaches 90 minutes, it adds 60 minutes and begins another control. Furthermore, it does this separately for each side, i.e. it adds 60 minutes to each side when that side reaches 90 minutes. If 40 moves have not been played, it is up to the opponent to call the time forfeit when the clock goes into the second control.
But if the move counter is set, it adds 60 minutes when the move count reaches 40. In this case, if there is a time forfeit, the clock stops at 0:00 on the side whose time has expired, but continues running on the other side. If, however, the players play on without calling the time forfeit, then (on some models and/or in some modes, at least) when move 40 is reached, the clock on the side showing 0:00 restarts at 60 minutes.
It’s the old “should” language issue, open to interpretation. The language is stronger in the 4th Edition, where ‘flag substitutes’ are described as “both legal and highly desirable.”
This might stem from USCF’s plan to corner the market on what was then called the Allegro clock, back in the mid-1990s.
Now, it is clear from this that if the only means a clock has for indicating that a player’s time has been exhausted is a beep, the beeping feature must be turned on. But I see nothing in the rule to indicate that if a clock has more than one means by which it can indicate that a player has run out of time, all such features must be turned on.