got a clock that can do this?

The official rules of the current FIDE championship match state "The time control for each game shall be: 120 minutes for the first 40 moves, 60 minutes for the next 20 moves and then 15 minutes for the rest of the game with an increment of 30 seconds per move starting after move 61 has been made."

My Chronos clock has around 70 modes, but I am aware of no Chronos modes that would implement an increment on a certain move.  Is there any clock that can do this?

It's not just "a certain move" though... it's a delay that applies during the 3rd time-control, right?

1. Two hours to make 40 moves

2. Another hour to get to 60 moves

3. Then 15 minutes for the game, with a 30-second increment

My clock (a DGT XL) can do it.

The rule specifies "after move 61" separately from the period lengths.  My Chronos and your DGT XL can both handle your steps 1,2, and 3 exactly as you wrote them, but the increment would be used during the entire 3rd period.  If the 3rd period started at the completion of move 55, the increment would be applied erroneously to moves 56 through 61.  And what if move 61 occurred in the 2nd period?

The 3rd period starts with move 61 by definition. Why do you think it could start earlier?

I must disagree.  I have played many games with an initial time control of 40 moves in 2h and gotten to 50+ moves before the 2h mark.  If that happens, I just have extra time to complete move 60 before the second period ends.

@TyrannusVerticalis Once you get to move 41, time is added to your clock and the second period starts. Once you complete move 60, time is added to your clock and the third period starts. If you make moves 1-60 in 3 seconds, it's still the 3rd time period.

Well, I have a DGT 2010 here. I will check that occasionally. But since they are using DGT XL clocks for the world championship games, I am pretty sure that they behave correctly. Are you sure you are using the right mode?

I typically don't use the move-counting modes.  But let me see if I understand all of you correctly using a simpler example: 40 moves in 120 minutes followed by game in 60m.

I complete move 40 after 100m of play.  I think the first period continues for the full 120m, so the total time available to me for the game is 180m.  I think you are saying that the first period ends after move 40 (at 100m) so the total time is reduced to 160m.

After move 40, 60 minutes is added.  Time won't be reduced after a time control is met.  In your example, at move 40 you would have 20 minutes left, so after you make move 40, you would have 80 minutes left.

Suppose you can take $100 from the bank every Saturday.  You start with $100 on Sunday and only spend $80, leaving you with $20.  You pull up to the bank on Saturday and take out $100.  How much money do you have now?  Not $100.  Not $20.  You have $120.

Same with the clock.  If you finish the first period (i.e. move 40) with 20 minutes left and you get 60 minutes more, your clock will show 80 minutes (or 1:20).  You'll also get any delays or increments scheduled for the second period.

Finally, in post #3, you wrote "If the 3rd period started at the completion of move 55".  But this can't happen.  You can reach the third period before 180 minutes, but you can't reach it before 60 moves.  So if you run out of time (i.e. the second period ends) before move 60, you simply lose on time.

OK, I think I understand.  We all agree that a time control of 40/120:G/60 would give each player 180 minutes total for the game, regardless of how the clock is set to display.  I will experiment with the move-counter options of my clock.  Thanks for the help.

Of course relying on a clock's move counter can be problematic due to the clock's counter getting out of synch with reality.  For example, inexperienced player A does not realize his king is in check, makes an illegal move, and starts opponent B's clock (maybe B was elsewhere wandering around the room).  Opponent B would inform him of the check and restart A's clock; then the clock's move counter would show 1 greater than the count on the scoresheet, and a time control period could end on the wrong move.

The TD must be able to figure out how to do that on a Digital clock as well.
A TD told me this. He borrowed my DGT2010 to figure it out.
Danish Chess Union wrote a letter to all TD you are required to learn to adjust time on digital chess clock as well.
if you purchase a clock where you cannot do that then you are not allowed to use it in a tournament.

I have scrutinized my Chronos manual, played with the clock, and find that it does not have a move-count mode that can handle the time control described in the original post of this thread.  Mine is an early model from 1998 or 99.  Newer models may have additional move-count modes that can do it, but I can't find anything online that I consider hard evidence of this.  My old Chronos also can't handle the standard FIDE control of "90 minutes for the first 40 moves followed by 30 minutes for the rest of the game with an addition of 30 seconds per move starting from move one" (from http://www.fide.com/component/handbook/?id=39&view=category ).

I ordered a DGT 2010, the "official" FIDE clock, after reading its online manual.

Thanks for the information; that manual demonstrates that modern Chronos clocks have sufficient capability.

However my 13-year-old Chronos, which is a longer one, does not have the TC- modes or any equivalent modes.  It does have move-counter modes and increment modes but can't do both simultaneously.  It has a couple of FD (FIDE) modes but these do not include delay or increment options, which were probably not FIDE standards back in the 1990s.  So I need a new clock, regardless.

Probably no one is still interested in this topic, but I want to report the final result of my research.

I discovered that the DGT 2010 does FIDE-style increments, as expected of a FIDE-approved clock; however, it does not handle USCF-style delays.  The DGT North American model does that.

I returned the DGT 2010 and got a new Chronos GX.  As mentioned by Shadowknight911 in post #18 of this thread, the GX can handle all possible delay and increment modes with or without move-counting.

And the only one that does for example 2h/40 + 1h/20 + 30min plus 15sec is the DGT XL.

Bronstein (as implemented on the 2010) and USCF delay (as implemented on the North American) are functionally equivalent. They only differ in what the display shows, not how much time you actually have to make any given move.

If T is the main time left, and D is the delay left for the current move, the 2010 shows T+D, whereas the NA shows just T. For both clocks, you have T+D before your flag falls.

Any given sequence of move times that leads to a flag fall results in the flag falling at the exact same time on both.